PH 12 Drugs for Pain Management PDF

11 Drugs for Pain Management LEARNING OUTCOMES 1. List the names, actions, possible side effects, and adverse effects of opioid agonists. 2. Explain what to teach patients and families about opioid agonists. 3. List the names, actions, possible side effects, and adverse effects of opioid agonist-an...

11 Drugs for Pain Management LEARNING OUTCOMES 1. List the names, actions, possible side effects, and adverse effects of opioid agonists. 2. Explain what to teach patients and families about opioid agonists. 3. List the names, actions, possible side effects, and adverse effects of opioid agonist-antagonists. 4. Explain what to teach patients and families about opioid agonist-antagonists. 5. List the names, actions, possible side effects, and adverse effects of nonopioid centrally acting analgesics. 6. Explain what to teach patients and families about nonopioid centrally acting analgesics. 7. List five common types of miscellaneous drugs used to help manage pain and the types of pain they most commonly relieve. KEY TERMS acute pain (ă-KYŪT PĀN, p. 211) Pain that is usually related to an injury, such as recent surgery, trauma, or infection, and ends within an expected time frame. addiction (ă-DĬK-shŭn, p. 216) A psychological dependence in which there is a desperate need to have and use a drug for a nonmedical reason. The addicted person has a limited ability to control this drug craving or use. analgesic (ă-nĕl-JĒ-zĭk, p. 213) Drugs that have the specific purpose of relieving pain either by changing the patient's perception of pain or by reducing painful stimulation at its source. chronic pain (KRŎ–ĭk PĀN, p. 211) Any pain that continues beyond the expected time frame of an acute injury process and that does not trigger the stress response. corticosteroid (kōr-tĭ-kō-ˈSTĔR-oid, p. 220) Drugs with powerful antiinflammatory actions that are chemically similar to the glucocorticoid hormones secreted by the adrenal glands. dependence (dē-PĔN-dĕns, p. 216) A state in which the body shows withdrawal symptoms when the drug is stopped or a reversing agent is given. miscellaneous analgesic (ă-nĕl-JĒ-zĭk, p. 220) Drugs that have specific purposes and actions for other health problems but can help provide relief for certain types of pain. 387 nonopioid centrally acting analgesic (Ō-pē-ŏyd, p. 218) Drugs that work in the CNS to help manage pain but do not interact with opioid receptors to do so. opioid (Ō-pē-ŏyd, p. 214) Any substance either derived from natural opium or that is chemically similar to opium that alters the perception of pain and has the potential to induce dependence and addiction. opioid agonist (Ō-pē-oid Ă-gă-nĭs, p. 214) Any drug that “turns on” (activates) the opioid receptors to change a patient's perception of discomfort and pain. opioid agonist-antagonist analgesics (Ō-pē-ōīd Ă-gă-nĭst ăn-TĂ-gĕ-nĭst, p. 217) Pain-management drugs that have mixed actions at opioid receptor sites. pain (PĀN, p. 210) An unpleasant sensation or emotion that produces or might produce tissue damage. pain threshold (p. 211) The smallest amount of tissue damage that makes a person aware of having pain. skeletal muscle relaxants (p. 221) Drugs that depress the CNS to reduce muscle spasms. tolerance (TŎL-ŭr-ŭns, p. 216) A drug-related metabolism problem that causes the same amount of drug to have less effect over time. withdrawal symptoms (wĭth-DRĂWL, p. 216) Changes in the body or mind, such as nausea or anxiety, that occur when a drug is stopped or reduced after regular use. Pain Pain Definition Pain is defined by the International Association for the Study of Pain as an unpleasant sensation or emotion that produces or might produce tissue damage. Pain is always a subjective experience; that is, pain is a sensation the patient feels and that cannot be felt or measured by someone else. This means that pain is personal to you. As a result, the important rule to remember is that pain is whatever the patient says it is, occurring whenever the patient says it occurs and at the intensity the patient states. All people experience pain a little differently because pain perception also includes behavioral, psychological, and emotional factors. Pain is a very common problem and a main reason why people go to a healthcare provider. Memory Jogger Pain is whatever the patient says it is, occurring whenever the patient says it occurs and at the intensity the patient states. The smallest amount of tissue damage that makes a person aware of having pain is the pain threshold. It is the point that a person first feels any pain. The pain threshold is different for every person and varies from one body site to another. For example, a small blister on a fingertip usually is perceived as more painful than the 388 same-size blister on the back. Factors such as age and the presence of other diseases also affect pain threshold. Most drugs used for pain management change (raise) the patient's pain threshold. Pain is initially classified as either acute pain or chronic pain. Acute pain is usually related to an injury, such as recent surgery, trauma, or infection, and ends within an expected time frame. Accidentally hitting your thumb with a hammer is an example of acute pain. One of the main features of acute pain is your body's physical response to it. Acute pain triggers the stress response (sometimes called the fight-or-flight response), resulting in elevated heart and respiratory rates, increased blood pressure, sweating of the palms and soles, dry mouth, and dilated pupils. The person who has acute pain is often restless and unable to concentrate. Chronic pain is any pain that continues beyond the expected time frame of an acute injury process. Some definitions of pain suggest that pain must exist for at least 6 months to be considered chronic, but that is a very long time to be in pain. People with cancer-related pain or chronic disorders (e.g., arthritis, shingles, or lower back pain [sciatica]) are experiencing chronic pain. It does not trigger the stress response because it has been present for so long that the body has adapted to it. As a result, the person with chronic pain does not have the physical responses seen with acute pain. Chronic pain may hurt less on some days than others but is usually always present. Causes may be difficult to find. This problem has often led to family members and healthcare workers not believing the patient's reports of pain presence and intensity. Chronic pain is often hard to relieve, may interfere with activities of daily living (ADLs), and greatly reduces quality of life. Memory Jogger Acute pain is usually related to an injury, such as recent surgery, trauma, or infection, and ends within an expected time frame. It triggers the stress response. Chronic pain is any pain that continues beyond the expected time frame of an acute injury process. It does not trigger the stress response because the body adapts to pain sensation over time. Pain is also classified by time of presence, as well as by specific sensation and cause (Table 11.1). Some pain has a constant presence, and other pain comes and goes (is intermittent). Cancer pain has many causes and sensations that can influence the times when pain is felt. Thus cancer pain is complex and often requires more than one drug type to manage it. Table 11.1 Classification of Pain CATEGORY CHARACTERISTICS EXAMPLE Acute Postsurgical pain, traumatic injury, bone fracture, infection Chronic Continuous Intermittent Nociceptive Sudden onset; has a specific cause; triggers the stress response with changes in breathing, heart rate, blood pressure; improves with time and healing Continues beyond the usual course of an acute injury process; may not have an identifiable cause; does not trigger the stress response; is usually present continuously Always present but may vary in intensity Comes and goes Specific to a body area that is easy to identify and describe; Arthritis pain, sciatica, shingles Sciatica Abdominal cramping from constipation or intestinal irritation Cuts, fractures, arthritis 389 Visceral Neuropathic Cancer pain words used to describe often include aching and throbbing Hard to locate, may be referred to more distant sites than the cause of the pain; often described as continual aching Sharp, shooting, stabbing, and burning sensations Often includes all specific types of pain with multiple causes (organ compression, tissue stretching, nerve compression, bone pain, etc.); complex; requires multiple types of agents for best relief Pain under the right shoulder blade with gallstone disease Diabetic neuropathy, trigeminal neuralgia, pain with shingles Usually advanced cancers that have spread beyond the originating site and are pressing on nerves and/or organs, putting pressure on the inside of bones, secreting chemicals that make pain receptors more sensitive, causing inflammation How Pain Is Perceived Pain is actually recognized (felt or perceived) in the brain rather than in the body area where it occurs. When a body part is injured, for example, when you drop a hammer on your toe, the toe is injured. This injury stimulates pain nerve endings in the toe that then send (transmit) electrical nerve impulses as a signal from the toe along nerves to the spinal cord. At the spinal cord the original signal is transferred to special pain nerve tracts up the spinal cord to the area of the brain where toe activity is located. At this point the signal is transferred to the brain and you now become aware of (perceive or “feel”) the pain in your toe (Fig. 11.1). Then you can make and carry out plans to put ice on your toe and let someone else do the hammering. FIG. 11.1 A sensory pathway for pain perception. (From Workman ML, LaCharity LA: Understanding pharmacology, ed 2, St. Louis, 2016, Elsevier.) You feel pain only in the brain, so anything that interferes with the transmission of the pain signal from your toe along the nerve to and in your brain can change if and how you perceive pain. So if you had a stroke that damaged the part of the brain 390 where toe pain would be perceived, you would not feel that pain. If the pain nerve tracts in the spinal cord were severed, you would not “feel” the pain in your toe even though the injury is severe. Also, if the nerves in your leg were severed, the pain signals would not reach the brain and you would not feel the toe pain. Anxiety, depression, fatigue, and other chronic diseases may increase the perception of pain. Activities that distract the patient, create positive attitudes, or provide support may reduce the perception of pain. Examples of these activities include listening to music, massage therapy, cold or hot packs, hydrotherapy, acupuncture, biofeedback, relaxation therapy, art therapy, hypnosis, therapeutic touch, Qigong or Reiki energy therapies, or use of transcutaneous electrical nerve stimulation units. Usually these nondrug therapy techniques are used with analgesics for optimum pain management. Principles of Pain Management Although pain is a common problem, it is often poorly addressed. Based on the idea that pain is unpleasant and should be relieved, the Agency for Healthcare Research & Quality originally developed specific principles for pain management regardless of the source or type of pain. These principles are: • Ask about pain on a regular basis. Drugs are to be given regularly and are more effective if given before the patient is in severe pain and miserable. Addiction is generally not a concern, especially for patients with chronic pain or terminal illness. • Assess pain systematically. Use pain intensity scales (Figs. 11.2, 11.3, and 11.4). 391 FIG. 11.2 Common pain measurement scales. (From Black JM, Hawks JH: Medical-surgical nursing: clinical management for positive outcomes, ed 8, Philadelphia, 2009, Elsevier.) FIG. 11.3 Wong-Baker FACES pain rating scale. (Copyright 1983, Wong-Baker FACES Foundation, www.WongBakerFACES.org. Used with permission. Originally published in Whaley & Wong's nursing care of infants and children. © Elsevier Inc.) 392 FIG. 11.4 The FLACC pain rating scale for infants and patients who are not alert. (From Workman ML, LaCharity LA: Understanding pharmacology, ed 2, St. Louis, 2016, Elsevier.) • Believe the patient and family in their reports of pain and what relieves it. • Choose pain-management options that are appropriate for the patient, family, and setting. The healthcare provider who makes this decision should be aware of the wishes of the family and the individual. • Deliver interventions in a timely, logical, and coordinated fashion. • Empower patients and their families. • Enable them to manage their pain to the greatest extent possible. Analgesic Drugs for Pain Management Many nerve paths carry the sensation of pain from an injured part of the body to the brain. This means that there are different places to block or alter the sensation of pain. Some pain may be relieved by nondrug therapies such as exercise, heat, ice or cold compresses, music, massage, diversion techniques, sedation, and rest; changing the room to be quieter, darker, or cooler; or other methods such as herbal poultices or acupuncture. Pain that is more severe often requires a management strategy of a combination of nondrug and drug therapies. A wide range of drugs are used in managing pain. Some of these drugs are actual analgesics, which have the specific purpose of relieving pain either by changing the patient's perception of pain or by reducing painful stimulation at its source. The word analgesia means absence of the sensation of pain. The analgesic categories are opioid agonists (narcotics), opioid agonist-antagonists, nonopioid centrally acting analgesics, and miscellaneous analgesics, which include a variety of drug types with 393 other purposes that also help reduce pain. Which specific type of drug is prescribed depends on the type of pain being experienced, the cause of the pain, pain intensity, expected duration of the pain, and the patient's perception of the pain. Memory Jogger The four main categories of drugs used for pain management are: • opioid agonists • opioid agonist-antagonists • nonopioid centrally acting analgesics • miscellaneous analgesics Opioid Agonist Analgesics Many drugs used for managing severe pain are opioids. An opioid (also called a narcotic) is any substance either derived from natural opium (from the poppy plant) or that is chemically similar to opium that alters the perception of pain and has the potential to induce dependence and addiction. Opium includes many chemicals, such as morphine, codeine, and heroin. In addition to natural opioids, synthetic opioids have been developed by drug companies. Both natural and synthetic opioids are useful for pain management. Morphine is the basic chemical from which the synthetic opioid analgesics hydrocodone, hydromorphone, fentanyl, and oxycodone have been developed. All natural and synthetic opioids are high-alert drugs because they have an increased risk for causing patient harm if given in error. Opioid agonists have a relatively high potential for abuse. In efforts to limit the abuse of these drugs, the federal government has regulations that describe who may prescribe or give opioids (see Chapter 2). You must learn and follow these rules to practice legally. Nurses usually have the responsibility for keeping opioids in a safe place, typically a locked cabinet, and account for their use in the hospital or nursing home setting. As stated earlier, morphine is the main opioid agonist analgesic, and it is the drug with which all other pain-management drugs are compared for effectiveness. Table 11.2 shows the equianalgesic dosages needed for common opioid agonists to achieve equal pain relief. Although different opioid agonist analgesics vary by strength (some are stronger than morphine and some are not as strong as morphine), they all work in the same way and all have the same side effects and adverse effects. Morphine and other strong opioid agonists are used often in acute care and also in hospice settings for patients who have severe pain. Codeine, hydrocodone (Hydromet), and oxycodone (OxyContin) are weaker than morphine and are often used in combination with acetaminophen in the outpatient setting. On the other hand, hydromorphone (Dilaudid) is much stronger than morphine. Table 11.3 lists dosages and nursing considerations for common opioid agonists. Table 11.2 Equianalgesic Adult Dosages of Common Opioid Agonists and Opioid 394 Agonist-Antagonists EQUIANALGESICa DOSE DRUG Opioid Agonists morphine codeine (many brand name combination drugs) fentanyl (Actiq, Apo-fentanyl , Duragesic, Lazanda) hydrocodone (Hycet, Lortab, Norco, Vicodin, and many brand name combination drugs) hydromorphone (Dilaudid, Apo-Hydromorphone ) oxycodone (Endocodone, Oxaydo, OxyContin) oxymorphone (Numorphan, Opana) Opioid Agonist-Antagonist buprenorphine (Buprenex, Probuphine) butorphanol (Stadol) nalbuphine (Nubain) pentazocine (Talwin) 30 mg (oral) 10 mg (parenteral) 200 mg (oral) NOT RECOMMENDED 120 (parenteral) 0.2 mg (transdermal patch) 0.1 mg (parenteral) 30 mg (oral) 7.5 mg (oral) 1.5 mg (parenteral) 20 mg (oral) 10 mg (oral) 1 mg (parenteral) 0.4 mg (parenteral) 2 mg (parenteral) 10 mg (parenteral) 150 mg (oral) 60 mg (parenteral) a Equianalgesic means the dose that provides about the same degree of pain relief that is provided by 30 mg oral morphine. Indicates Canadian drug. Table 11.3 Dosages and Nursing Implications for Common Opioid Agonists All opioid agonist analgesics work by binding to mu opioid receptor sites (activating them) in the brain and other areas, changing the person's perception of pain. DRUG/ADULT DOSAGE RANGE NURSING IMPLICATIONS codeine 15–60 mg every 4 hours (oral and parenteral) • Reassess the patient's level of pain within an hour after giving an opioid to determine its effectiveness. fentanyl (Actiq, Apo-fentanyl , Duragesic, Lazanda) 50–100 • During periods of acute pain, encourage the patient to take the drug on the prescribed mcg IM or by slow IV over 1–2 minutes; 12–100 mcg/hr by schedule for best pain relief. Assess elimination status daily because all opioids cause transdermal patch constipation. hydrocodone (Hycet, Lortab, Norco, Vicodin, and many brand • Assess respiratory rate and pulse oximetry frequently because opioids can cause name combination drugs) 10–40 mg orally every 12 hours respiratory depression. hydromorphone (Dilaudid, Apo-Hydromorphone ) 2–4 mg • If patients cannot be aroused, have respirations below 8 per minute, have severe orally every 4–6 hours; 0.2–1 mg IV every 2–3 hours morphine 2–4 mg orally every 4–6 hours; 0.2–1 mg IV every 2–3 hypotension, or develop hypothermia, notify the healthcare provider immediately to prevent coma or death. hours oxycodone (Endocodone, Oxaydo, OxyContin) 5–30 mg every 4 • Patients may also be prescribed stimulant laxatives because of the high incidence of constipation common with opioids. hours (immediate release); 10 mg every 12 hours (extended • Instruct patients who are taking extended-release tablets or capsules not to chew, release) open, crush, bite, or cut them, to prevent rapid absorption of excess drug. oxymorphone (Numorphan, Opana) 5–20 mg orally every 4–6 • Instruct patients not drink alcohol or take other CNS depressants while on an opioid hours; 0.5–1.5 every 4–6 hours parenterally analgesic because the CNS effects are intensified. • Change fentanyl patches and rotate sites at least every 72 hours and wash the skin under the old patch to prevent excess drug absorption. Indicates Canadian drug. Memory Jogger Strong opioid agonist analgesics such as hydromorphone and fentanyl require less drug (lower dosages given less often) to result in the same level of pain relief as weaker opioid agonist analgesics. Action Did you know you actually make your own internal morphine? Your brain has opioid receptors because you do make your own internal opioids to provide some pain relief and an increased sense of well-being when physically stressed. These internal morphine-like chemicals produced in the brain are endorphins, enkephalins, 395 and dynorphins. Think about the jogger who runs for 10 miles, looks terrible, and says, “I feel wonderful.” How is this possible? With the physical stress and hard work of running 10 miles, the brain makes much more of these substances. They then bind to specific opioid receptors in the brain and activate the receptor to change your perception from discomfort and pain to comfort. So these internal opioids are opioid agonists because they “turn on” (activate) the opioid receptors to change the runner's perception of discomfort. External opioids that are given for pain relief also bind to opioid receptors as agonists to activate the opioid receptors. (You may need to review the action of agonists, antagonists, and receptors that was discussed in Chapter 3). Morphine and all opioid agonist analgesics work by binding to opioid receptor sites in the brain and other areas. The main opioid receptors are mu (OP3), kappa (OP2), and delta (OP1). When a drug binds to and acts as an agonist at mu receptors, the responses include pain relief, some degree of respiratory depression with slower breathing, some sleepiness or sedation, decreased intestinal motility with constipation, pupil constriction, lower blood pressure, and euphoria (a feeling of emotional happiness). When a drug binds to and acts as an agonist at kappa receptors, the responses include some pain relief, sedation, pupil constriction, and dysphoria (a state of feeling emotional or mental discomfort, restlessness, and anxiety). When a drug binds to and acts as an agonist at delta receptors, the responses include some pain relief, dysphoria, and hallucinations. Morphine binds most tightly and best to the mu receptor, acting as an agonist. This activates the mu receptors and the person's perception of pain is changed. Opioid agonists only change the perception of pain; they do nothing at the site of injured tissue to reduce the cause of pain. Some drugs act as an agonist at one type of opioid receptor site and, at the same time, act as an antagonist at other opioid receptor sites, providing mixed responses. The opioids that provide the best pain relief bind most strongly (tightly) to the mu receptors. Pain drugs that are strong morphine agonists include morphine, hydromorphone, oxymorphone, and fentanyl. Those that bind moderately well to the mu receptors and provide some degree of pain relief include codeine, hydrocodone, and oxycodone. Memory Jogger Strong opioid agonist analgesics include: • morphine • hydromorphone • oxymorphone • fentanyl Uses Opioid agonists are used to manage moderate-to-severe acute pain and chronic pain. They may be used preoperatively (before surgery) to treat pain from injury or other disease processes, for constant cough (codeine), postoperatively for pain, and for labor. Opioids are available in oral tablets, capsules, lozenges, and liquids; 396 intravenous and other parenteral solutions for injection; and some (such as fentanyl), as a continuous-release transdermal patch. Some opioids are also commonly available as combination products along with drugs such as acetaminophen, aspirin, caffeine, and barbital. This allows a small dose of opioid to be combined with other chemicals to relieve symptoms or calm the patient. Expected Side Effects The two most common side effects of opioid agonists are sleepiness (sedation) and constipation. Other expected reactions to opioid agonist analgesics include bradycardia (slower heartbeat), hypotension, decreased respirations, anorexia (lack of appetite), dry mouth, and a sense of happiness (euphoria). Most patients also have decreased pupil size (miosis), especially older adults, and are at increased risk for falling. Adverse Reactions Serious adverse reactions include very slow, shallow breathing (bradypnea) also known as respiratory depression, severe hypotension, decreased urine output (oliguria), below-normal body temperature (hypothermia), excessive sedation or coma, and cool, clammy skin. These serious reactions may indicate overdose and require immediate medical attention. The drug dose should be lowered or the drug discontinued when any serious reaction occurs. Top Tip for Safety Serious adverse reactions and symptoms of overdose for opioid agonist analgesics that require immediate medical attention are: • respirations of 8 or less per minute • very low blood pressure • excessive sedation or coma • below-normal body temperature If a serious adverse reaction or an overdose occurs with an opioid agonist, the effects can be reversed by giving an intravenous, IM, or subcutaneous opioid antagonist such as naloxone (Narcan) or naltrexone (Revia, Vivitrol). They work by binding tightly to the mu opioid receptors and blocking them so the opioid agonist cannot stay bound to them. In an emergency these drugs can be given without a prescription. Naloxone is also available as an intranasal spray, but this route is not as reliable as when given parenterally. Lifespan Considerations Older Adult 397 Older adults are more likely to have some degree of liver and/or kidney impairment that reduces their ability to metabolize and excrete opioid agonists. This makes them more sensitive to the drugs, and normal doses can cause serious adverse reactions. Older adults may require dosages to be lower or the drugs given less frequently. Tolerance, Dependence, and Addiction Tolerance is a drug-related metabolism problem that causes the same amount of drug to have less effect over time. Although tolerance can happen with any drug type, it is most often seen with opioid agonists. This happens because the body gradually increases the rate at which it degrades and eliminates the drug. In the case of pain, higher dosages are needed for relief. Dependence is a state in which the body shows withdrawal symptoms when the drug is stopped or a reversing agent is given. Withdrawal symptoms are changes in the body or mind, such as nausea or anxiety that occur when a drug is stopped or reduced after regular use. Tapering off (slowly taking less of the drug) can reduce withdrawal symptoms. Psychological dependence, or addiction, is the desperate need to have and use a drug for a nonmedical reason. The addicted person has a limited ability to control this drug craving or use. Tolerance and dependence result from regular use of an opioid for a certain length of time and should not be confused with or labeled as addiction. Addiction is a problem; however, a patient in pain should not be denied pain relief because of fear of addiction. Before beginning opioid therapy for noncancer pain management, recent recommendations are to obtain thorough medical and social histories, including tobacco and alcohol use, and a family history of addiction. All opioid agonists have the potential to cause tolerance and dependence, which are not the same as addiction or abuse, when taken on a long-term basis. Drug Interactions The decreased pupil size, sedation, dry mouth, and euphoria are the central nervous system (CNS) effects of the opioid agonists along with pain relief. These effects can be intensified and made much worse when the patient also uses certain other substances or drugs that act on the CNS. These agents include alcohol, antianxiety drugs, skeletal muscle relaxants, barbiturates, many drugs used for psychiatric disorders, and other opioid agonists. Top Tip for Safety The sedating and slowed breathing effects of opioid agonist analgesics are intensified and made worse when the patient also drinks alcohol or uses antianxiety drugs, skeletal muscle relaxants, barbiturates, many drugs used for psychiatric disorders, and other opioid agonists. Be sure to determine which other drugs the patient also takes. Nursing Implications and Patient Teaching Assessment. 398 Before a patient can be effectively helped with pain relief, it is important to determine the cause of the pain and its intensity. Do not simply give drugs prescribed for pain without understanding the source and intensity of the pain. Even in a patient with terminal cancer, assess each new pain for a specific cause that may have a more focused treatment. Ask the patient to describe the pain and use a pain scale to assess pain intensity (severity). Fig. 11.2 shows several examples of pain rating scales for patients who are alert to indicate how much pain they are having. Fig. 11.3 shows an example of a pain rating scale for children and adults who may have trouble expressing their thoughts. Ask the patient whether he or she has ever received morphine (or other opioid agonist) in the past and what, if any, problems occurred with its use. When opioids are first prescribed, ask the patient about current tobacco and alcohol use, any past addiction to pain drugs, or a family history of substance abuse or addiction. Lifespan Considerations Pediatric: Pain Assessment Children experience pain in the same way as adults, but young children may have difficulty communicating their level of discomfort. Use an age-appropriate rating scale to assess pain in younger pediatric patients. When assessing pain in infants, pay attention to the infant's position (especially whether the legs are drawn up), facial expression, crying pattern, sleep/rest cycles, interest in eating, and how easily he or she can be consoled (see Fig. 11.4). Compare these observations with those obtained when the infant appears to be comfortable. Planning and implementation. Pain is best relieved when opioid agonists are given before the patient's pain becomes severe. This means they work better when given on a schedule rather than waiting until the patient asks for it. When the patient asks for another dose, check to see when the patient received his or her most recent dose of the prescribed opioid agonist to determine whether another dose can be given at this time. Also check the prescribed drug name and dose carefully. Opioid agonists are not interchangeable because drug strength varies. Only the prescribing healthcare provider can change the order. Be sure to sign out the dose as required by the Drug Enforcement Agency of the federal government. If this is the first dose of an opioid agonist the patient is to receive, before giving the drug, check his or her respiratory rate and oxygen saturation because these drugs can cause respiratory depression. This action is important to perform on older patients and for those who are receiving higher doses. Most patients become drowsy with opioid agonists; therefore it is important to ensure that the upper side rails are raised and the call light is in reach. If the patient is in a chair, remind him or her to call for assistance to avoid falls from drowsiness or low blood pressure. Evaluation. 399 Usually, opioid agonist analgesics begin to take effect in 15 to 30 minutes. Check the patient at this time for pain relief and for changes in respiratory rate and depth. Recheck at least every hour. Opioid agonist analgesics may slow the respiratory rate and decrease the cough and sigh reflexes; thus patients who have had surgery, especially those who have smoked for a long time, may develop areas where the lungs do not inflate well (atelectasis) or collect fluid and develop pneumonia. If pain relief is not obtained or is not sufficient to keep the patient comfortable, report this to the prescriber so that changes in pain management can be made. Higher doses and/or more frequent dosing may be needed. If the patient has been receiving an opioid agonist for 2 days or longer, ask him or her about constipation because this is a very common side effect of these drugs. If stool softeners or laxatives have been prescribed, give them as ordered. If they have not been prescribed and opioid agonist therapy is ongoing, remind the prescriber about the issue of constipation. The patient may need a laxative in addition to a stool softener. Patient and family teaching. Tell the patient and family the following: • Take this drug as prescribed and do not change the dosage. For acute pain, it is most effective to take the drug before you have severe pain, if possible on a regular schedule. Write down the time when the drug was last taken to prevent taking too much by accident. • Do not take any other drugs not prescribed by your healthcare provider. • Alcohol increases the effects of the drugs, and taking both together may lead to serious adverse reactions. • Report any new symptoms or problems to your healthcare provider. • Change positions slowly to prevent dizziness and falling from a rapid drop in blood pressure. • Do not drive, operate heavy machinery, or make important decisions while under the influence of the drug because your judgment may be impaired. • Increase fluid and fiber intake to prevent constipation. • Use prescribed stool softeners or laxatives to prevent severe constipation. • Take oral opioids with food to prevent nausea. • If the opioid agonist is an extended-release tablet or 400 capsule, do not cut it in half, chew it, or crush it because the time-release feature will be ruined and too much drug may be absorbed too quickly and cause adverse reactions. • Do not allow anyone else to use the drug. Opioid Agonist-Antagonist Analgesics Opioid agonist-antagonist analgesics are pain-management drugs that have mixed actions at opioid receptor sites. Although not as strong as opioid agonist analgesics, they are thought to be at lower risk for addiction or abuse because of some of the side effects. Action Four opioid agonist-antagonists are available for pain relief (Table 11.4). Three of them (pentazocine, nalbuphine, and butorphanol) act as antagonists at the mu opioid receptors and as agonists at the kappa opioid receptors. This action makes them less effective for pain control than pure opioid agonists. They do still provide pain relief because, as described in the earlier Opioid Agonist Analgesics section, activation of the kappa receptors results in some pain relief, as well as sedation. The fourth drug, buprenorphine, is different because it acts as a partial agonist at mu receptors and as an antagonist at kappa receptors. This allows buprenorphine to have greater pain relief potential than the other three and less dysphoria. The sensation of dysphoria, which is a state of feeling emotional or mental discomfort, restlessness, and anxiety, is unpleasant and decreases the likelihood that patients would want to use these drugs when they are not in pain. Table 11.4 Dosages and Nursing Implications for Common Opioid Agonist-Antagonists Most opioid agonist-antagonists antagonize (block) the mu receptors and change the perception of pain by agonizing the kappa receptors. Buprenorphine is a partial mu agonist. DRUG/ADULT DOSAGE RANGE NURSING IMPLICATIONS buprenorphine (Buprenex, Probuphine) • Reassess the patient's level of pain within an hour after giving an opioid agonist-antagonist to determine 0.3 mg IM or IV every 6–8 hours its effectiveness. butorphanol (Stadol) 1–4 mg IM or 0.5–2 • Assess the patient's emotional responses because butorphanol, nalbuphine, and pentazocine can cause mg IV every 3–4 hours dysphoria, anxiety, nightmares, and hallucinations. nalbuphine (Nubain) 10 mg IM, IV, or • Assess heart rate and rhythm frequently because these drugs can excite the cardiac system and cause subcutaneously every 3–6 hours dysrhythmias. pentazocine (Talwin) 30 mg IV or 30 mg • Avoid the use of butorphanol, nalbuphine, and pentazocine in a patient who is physically dependent on an IM/subcutaneously every 3–4 hours opioid agonist because blocking the mu receptor can cause withdrawal symptoms. Memory Jogger The opioid agonist-antagonist analgesics are: • pentazocine • nalbuphine 401 • butorphanol • buprenorphine Uses The greatest use of the opioid agonist-antagonist analgesics is for relief of mild-tomoderate pain. They are less useful for severe pain. Pentazocine is available in an oral as well as a parenteral form. The three that are antagonists at the mu opioid sites have only limited problems with respiratory depression. Buprenorphine also has less respiratory depression than pure opioid agonists because it only partially agonizes the mu receptors. Nalbuphine and butorphanol are sometimes used to manage pain during labor and delivery. Butorphanol may be prescribed as a metered-dose nasal spray for management of migraine headaches. Expected Side Effects Common mild side effects are similar to those for morphine. These include sedation, constipation, and constricted pupils. Adverse Reactions Higher doses of these drugs are associated with nightmares and hallucinations. The opioid agonist-antagonists can have serious cardiac reactions. Pentazocine, nalbuphine, and butorphanol excite the cardiac system, making the heart work harder and elevating blood pressure. They should not be used in patients who are suspected of having a heart attack, and they should be used carefully in those who have heart failure. Buprenorphine can cause serious cardiac dysrhythmias and should not be used for patients who have other serious dysrhythmias. Although respiratory depression is possible with these drugs, it is not common. Use of pentazocine, butorphanol, or nalbuphine in a patient who is physically dependent on morphine or other opioid agonists will cause withdrawal symptoms. This occurs because they block mu receptor sites. The use of these three drugs in a patient who is physically dependent on opioid agonists is avoided. Drug Interactions The sedating effect of these drugs is made worse with alcohol, antianxiety drugs, skeletal muscle relaxants, barbiturates, many drugs used for psychiatric disorders, and pure opioid agonists. Be sure to determine which other drugs the patient also takes. Nursing Implications and Patient Teaching Assessment. Assess the patient's pain in the same way as for opioid agonists or any other type of pain-management drug. Ask the patient whether he or she has ever taken any of these specific drugs and whether any problems resulted from taking it. Also ask what other over-the-counter and prescribed drugs the patient has taken in the past 24 hours, especially any opioid agonist analgesics. 402 Planning and implementation. Planning, implementation, evaluation, and patient and family teaching activities are the same as for opioid analgesics. Nonopioid Centrally Acting Analgesics Nonopioid centrally acting analgesics are drugs that work in the CNS to help manage pain but do not interact with opioid receptors to do so. The two most commonly used drugs in this class are clonidine (Duraclon) and tramadol (Ultram, Ryzolt). Memory Jogger Two common nonopioid centrally acting analgesics are: • clonidine • tramadol Action Clonidine and tramadol have completely different mechanisms of action for pain relief. Clonidine is an antihypertensive drug most commonly used to lower blood pressure. It works for pain management by binding to specific receptors (alphaadrenergic receptors) in the spinal cord and blocks their activity. This action keeps pain signals from the source of the pain from traveling to the level of the brain. As a result, fewer pain signals reach the brain to be “felt” as pain. Clonidine does not change the conditions at the source of the pain. Although it has a chemical structure similar to codeine, tramadol has only weak effects at opioid receptors. Instead it works by blocking the action (inhibiting) some of the neurotransmitters in the spinal cord and areas of the brain. This action reduces pain signal transmission to brain sites that perceive pain. The usual adult dosage ranges for tramadol are 50 to 100 mg orally every 6 hours (immediate-release tablets) and 100 to 200 mg every 12 hours (extended-release capsules). Uses Clonidine formulated for pain management (Duraclon) is approved for severe pain (often cancer pain) and is given as a continuous epidural infusion. It is not a controlled substance because it is considered to have no potential for addiction or abuse. The oral formulation (Catapres) is only for blood pressure control and does not have a role in pain management. Tramadol is an oral drug used for moderate or moderately severe acute pain. It is only as effective as codeine (not as effective as morphine) and is often used along with acetaminophen. Expected Side Effects Clonidine dilates blood vessels, which can lead to severe hypotension. It should not 403 be used in patients who have low blood pressure. Tramadol has mild side effects of sedation, dizziness, dry mouth, and constipation. Adverse Reactions Tramadol can induce seizures and should not be used in any patient who has epilepsy or any other neurologic disorder. Drug Interactions Clonidine, because it is given by epidural, has no direct drug interactions. However, if a patient also takes another drug for blood pressure management, even epidural clonidine can make hypotension worse. Tramadol has CNS and brain effects; therefore the sedating and other CNS effects are made worse with alcohol, antianxiety drugs, skeletal muscle relaxants, barbiturates, many drugs used for psychiatric disorders, and opioid analgesics. Be sure to determine which other drugs the patient also takes. Nursing Implications and Patient Teaching Assessment. Assess the patient's pain in the same way as for opioid agonists or any other type of pain-management drugs. Ask the patient whether he or she has ever taken any of these specific drugs and whether any problems resulted from taking it. Also ask what other over-the-counter and prescribed drugs the patient has taken in the past 24 hours. For tramadol, determine whether the patient has a known seizure disorder or any other neurologic problem. If such a disorder is present, hold the dose and notify the prescribing healthcare provider. Planning, implementation, evaluation, and patient and family teaching activities are the same as for opioid analgesics. Acetaminophen Acetaminophen (Abenol, Atasol, Panadol, Tylenol, and many others) is a common drug used for pain relief. It can be purchased over the counter as a single drug or combined with other substances such as caffeine and aspirin (Excedrin). When combined with other pain-control drugs, especially opioid agonists, acetaminophen requires a prescription. It can be given orally in tablets, capsules, or liquids, or rectally in a suppository. A special formulation (Ofirmev) is available as an intravenous infusion. Action Acetaminophen acts only in the brain to reduce the production of prostaglandins, a body chemical that can cause inflammation in other body areas. In the brain, prostaglandins increases the perception of pain. By reducing the amount of prostaglandins in the brain, perception of pain is reduced. Acetaminophen does not act at the site of an injury that is causing pain and does not have anti-inflammatory actions. 404 Uses Acetaminophen alone is used to manage mild-to-moderate pain. It is often used for infants and children to reduce fever. In combination with other pain-control drugs, acetaminophen can help manage more severe pain. It is often used in place of aspirin or other NSAIDs for pain because acetaminophen does not increase the risk for bleeding. Also, children should not take aspirin because of its association with development of Reye syndrome. Acetaminophen comes in liquid, tablet, and capsule forms. The usual adult dose is 325 to 650 mg every 4 to 6 hours and should not exceed 3 g total daily. For children the usual dose is 7 to 15 mg/kg every 4 hours. The maximum total daily dose for children varies with the child's weight. Top Tip for Safety Acetaminophen has a maximum daily total dose to prevent organ damage. Expected Side Effects Side effects of acetaminophen are rare when it is taken at the recommended dosages, although an allergic reaction is always possible. The most common side effects are nausea and skin rash. Adverse Reactions One problem with acetaminophen is that because it is available without a prescription, people often believe that it has no adverse effects, which is not true. When taken at higher doses or for prolonged periods, acetaminophen is toxic to the liver, which can be damaged or destroyed. This is why there is a maximum total daily dose for this drug. Drug Interactions Many common over-the-counter drugs for sleep, colds, headaches, and allergies contain acetaminophen as one of the ingredients. These additional sources of acetaminophen must be added when calculating the total daily dose of acetaminophen. Liver damage occurs more rapidly when acetaminophen is taken with alcohol. Top Tip for Safety Acetaminophen can be toxic to the liver and should not be taken by anyone who already has liver health problems. Nursing Implications and Patient Teaching Assessment. Assess the patient's pain in the same way as for any other type of pain-management drug. Ask the patient whether he or she has ever taken acetaminophen (you may 405 have to use the most common brand name in your area, such as Tylenol) and whether any problems resulted from taking it. Also ask what other over-the-counter and prescribed drugs the patient has taken in the past 24 hours. Planning and implementation. Liquid oral acetaminophen comes in many strengths. Some liquid forms contain as few as 16 mg/mL, and others may contain as much as 70 mg/mL. Carefully check the strength to ensure the correct dosage, especially with infants and children. If you are not sure of your dosage calculations, check with another nurse, healthcare provider, or pharmacist. Acetaminophen can be given with or without food because it does not increase the risk for stomach ulcers. Evaluation. Within an hour after giving acetaminophen, assess the patient's pain level to determine effectiveness. Also ask the patient whether he or she noticed any other changes that may indicate a sensitivity to acetaminophen. Patient and family teaching. Tell the patient and the family the following: • Take acetaminophen as prescribed by your healthcare provider and not more often or at higher dosages. • Many over-the-counter drugs for colds, headache, allergies, and sleep aids also contain acetaminophen, as do some other drugs prescribed for pain. The acetaminophen in these drugs must be figured into the total maximum daily dose of 3 g for an adult along with any separate acetaminophen. • Do not drink alcoholic beverages on days when you take acetaminophen or any drug that contains acetaminophen to prevent liver damage. Lifespan Considerations Pediatric An infant or young child should never receive an adult dose of acetaminophen because of its severe liver toxicity. Teach parents to read the label on liquid acetaminophen bottles for infants and small children very carefully to ensure the correct dose for the child's size. Teach parents to call the nearest pharmacy and talk with the pharmacist to ensure that the dose is correct if they are unsure what dose to 406 give. Miscellaneous Drugs for Pain Management Miscellaneous analgesics are drugs that have specific purposes and actions for other health problems but can help provide relief for certain types of pain. These drugs can help reduce a person's perception of pain and often enhance the painmanagement effectiveness of other analgesics. They may be used alone or in combination with opioids. The most outstanding feature of nonopioid analgesics is that they are not chemically or structurally similar to opioids. As a result, they have less potential for dependence and addiction. Many of these nonopioid analgesics have other uses and are discussed in more detail elsewhere in this text. An overview of how they work and are used in pain control is provided in this section. Regardless of category, nursing responsibilities when giving nonopioid analgesics are the same as those described for opioid agonists. Pain assessment and determination of effectiveness in managing pain are still necessary. Memory Jogger Common miscellaneous drugs and classes of drugs used for pain management include: • acetaminophen • corticosteroids • NSAIDs • skeletal muscle relaxants • antidepressants • anticonvulsants Corticosteroids Inflammation usually causes pain. When tissue injury occurs, such as when you hit your thumb with a hammer or when you have a tooth pulled, the injured tissues release chemicals that start the inflammatory processes. These chemicals bind to pain receptors in the area and send pain signals along the nerve tracts to the brain. Also, these chemicals make the pain receptors more sensitive to any other stimulus. So even just touching the inflamed area can increase the pain. Corticosteroids are drugs with powerful anti-inflammatory actions that are chemically similar to the cortisol hormones secreted by the adrenal glands. These drugs are able to greatly inhibit the production of mediators that result in the actions and symptoms of inflammation. However, they have many side effects and adverse effects that limit their use for pain. The two most common oral corticosteroids used for pain are prednisone and methyl prednisolone. Corticosteroids can be given intravenously, topically, and as an epidural injection (usually for acute back pain). Chapter 12 provides a complete discussion of the actions and uses of corticosteroids, as well as the nursing responsibilities. 407 NSAIDs NSAIDs are nonopioid analgesics that have the main action of reducing inflammation. NSAIDs can help manage pain associated with inflammation, bone pain, cancer pain, and soft tissue trauma. Just like corticosteroids, NSAIDs drugs actually act at the tissue where pain starts and do not change a person's perception of pain. NSAIDs help stop tissue production of the chemicals of inflammation and reduce the symptoms of inflammation (pain, warmth, redness, swelling, and reduced use) in the area of injury. With inflammation reduced, pain also is reduced. Many NSAIDs are available over the counter and are commonly used for mild-to-moderate pain. Some of these same NSAIDs at higher dosages per tablet or capsule, as well as the stronger NSAIDs, require a prescription and are used for pain for only a limited period. Mild NSAIDs include salicylic acid (aspirin), ibuprofen (Advil, Motrin), and naproxen (Aleve, Anaprox, Naprosyn). Stronger NSAIDs include oxaprozin (Daypro), indomethacin (Indocin), nabumetone (Relafen), ketorolac (Toradol), piroxicam (Feldene), celecoxib (Celebrex), and meloxicam (Mobic). All NSAIDs work in much the same way and have many of the same adverse effects. Chapter 12 provides a complete discussion of the actions and uses of NSAIDs, as well as the nursing responsibilities. The most common NSAID in use today is salicylic acid, aspirin, which is available over the counter. A side effect of aspirin and many other NSAIDs is increased risk for bleeding. Aspirin affects blood clotting longer than do other NSAIDs. Other adverse effects include irritation of the stomach and intestinal tract, allergic reactions, and asthma. Stronger NSAIDs can raise blood pressure, cause water retention, and can damage the kidney. Aspirin should never be given to infants or children because of its association with the development of a very serious health problem known as Reye syndrome. Lifespan Considerations Pediatric Aspirin should never be given to infants or children because of its association with the development of a very serious health problem known as Reye syndrome. This disorder often leads to mental deficits, coma, or death. Skeletal Muscle Relaxants Skeletal muscles contract under nerve stimulation to allow you to move. So when you want to stand up from a sitting position, the motor area of your brain triggers the nerves that specifically control the muscles of your legs so that only those muscles contract for you to straighten your legs enough to lift you to a standing position. If for some reason the nerves connecting your brain to your leg muscles are not working, the muscles will not contract and no movement occurs. A skeletal muscle spasm is an unwanted overcontraction of one or more muscles. This often occurs when nerves controlling contraction to a specific muscle send an 408 inappropriate signal to that muscle. Common causes of inappropriate nerve signals include pressure on the nerve, swelling along the nerve path, and low blood calcium levels. Spasms also occur when a muscle is irritated or damaged. Pain from a spasm in a large muscle can be intense. If you have ever had a charley horse in your calf, you know how painful a muscle spasm can be. Action Skeletal muscle relaxants are drugs that act by depressing the CNS to reduce muscle spasms. This action slows signal transmission along motor nerves, which results in reduced muscle spasms and less muscle pain. The most commonly prescribed muscle relaxants are methocarbamol (Robaxin) and cyclobenzaprine (Flexeril) (Table 11.5). Table 11.5 Dosages and Nursing Implications for Common Skeletal Muscle Relaxants Skeletal muscle relaxants relieve the pain associated with muscle spasms by slowing contraction signal transmission in motor nerves. DRUG/ADULT DOSAGE RANGE NURSING IMPLICATIONS methocarbamol (Robaxin) 1.5 g orally every 6 • Before giving the first dose of either of these skeletal muscle relaxants, ask whether the patient has a hours or 1 g IM/IV every 8 hours seizure disorder because these drugs lower the seizure threshold. cyclobenzaprine (Flexeril) 5–10 mg orally every • Check the dose of methocarbamol carefully because it is in grams, not milligrams. 8 hours • Instruct patients who are taking extended-release tablets or capsules not to chew, open, crush, bite, or cut them, to prevent rapid absorption of excess drug. • Instruct patients not to drink alcohol or take other CNS depressants while on a skeletal muscle relaxant because the CNS effects are intensified. Uses Skeletal muscle relaxants are used for pain and insomnia when excessive skeletal muscle contractions or spasms contribute to these problems in adults. They are not usually used for children. Expected Side Effects Common side effects of methocarbamol are flushing, low blood pressure, slow heart rate, and fainting. Common side effects of cyclobenzaprine are dizziness, headache, dry mouth, blurred vision, and urinary retention. Adverse Reactions Serious adverse effects of methocarbamol are a high risk for allergic reactions and temporary memory loss (amnesia). It lowers the seizure threshold. Serious adverse effects of cyclobenzaprine are cardiac dysrhythmias and prolonged cardiac conduction. Cyclobenzaprine is not to be used in a patient who is recovering from a heart attack or who has a heart rhythm problem. It also should not be given to a patient who takes a monoamine oxidase inhibitor drug (which is usually used for psychiatric disorders) because of the risk for severe high blood pressure and high fever. Cyclobenzaprine also lowers the seizure threshold. Top Tip for Safety Methocarbamol and cyclobenzaprine should not be given to anyone who has a 409 seizure disorder because these drugs lower the seizure threshold. Drug Interactions The sedating and other CNS effects are made worse with alcohol, antianxiety drugs, skeletal muscle relaxants, barbiturates, many drugs used for psychiatric disorders, and opioid analgesics because skeletal muscle relaxants have CNS and brain effects. Be sure to determine which other drugs the patient also takes. Nursing Implications and Patient Teaching Assessment. Before giving a muscle relaxant to a patient for the first time, assess the level of consciousness, cognition, and skeletal muscle reactivity. Also ask the patient whether he or she has a seizure disorder or has ever had a seizure in the past because these drugs lower the seizure threshold. Before giving the first dose of cyclobenzaprine, assess the patient's blood pressure and radial and apical pulses for any skipped beats, extra beats, or any other type of irregular heartbeat. Top Tip for Safety Assess patients for irregularities before giving cyclobenzaprine. If you find any persistent heartbeat irregularity, notify the healthcare provider before giving the drug. Planning and implementation. After giving either muscle relaxant, assess for level of consciousness and degree of muscle relaxation or muscle weakness. Patients often become very drowsy and may fall. Raise the side rails and remind the patient to call for help to get out of bed. Help the patient change position slowly because these drugs can cause a sudden lowering of blood pressure. Teach him or her to sit for a few minutes on the side of the bed before attempting to get up. Help the patient during walking to prevent falling. Methocarbamol and cyclobenzaprine can both cause urinary retention. If a patient who is receiving one of these drugs has an enlarged prostate gland or is also taking a drug for overactive bladder, assess for signs or symptoms of urine retention. Symptoms include difficulty starting the urine stream, weak urine stream, and bulge in the lower abdomen. Evaluation. After giving the first dose of cyclobenzaprine, assess the patient's radial and apical pulses hourly for any skipped beats, extra beats, or any other type of irregular heartbeat. If you find persistent irregularity, notify the healthcare provider. Assess the patient's degree of comfort and muscle reflexes to determine effectiveness. 410 Patient and family teaching. Tell the patient and family the following: • These drugs are to be taken only on a short-term basis. Usually the drugs are prescribed for 2 to 3 weeks because of their potential for abuse. • Just like for any substance that causes sedation, avoid operating any dangerous equipment, driving a car, or making critical decisions while under the influence of these drugs. • Avoid alcohol because the sedation effect of these drugs is potentiated by alcohol. • If you are taking cyclobenzaprine take your pulse daily and report new-onset, persistent irregularities to your healthcare provider. Go to the nearest emergency department or call 911 if you develop shortness of breath or chest pain. Antidepressants Antidepressant drugs that improve long-term sense of sadness can reduce some types of chronic pain and cancer pain, especially neuropathic nerve pain with tingling and burning sensations. The most common antidepressants used for pain management are amitriptyline (Elavil), nortriptyline (Pamelor), paroxetine (Paxil), and sertraline (Zoloft). The oral doses of these drugs for pain management are often different than the doses used to manage depression. Antidepressants work for pain management by increasing the amount of natural opioids (endorphins and enkephalins) in the brain and also by reducing the depression that often occurs with chronic pain. Usually the patient must take an antidepressant for 1 or 2 weeks before he or she feels any relief from pain. Chapter 10 provides more discussion of the actions and uses of antidepressants, as well as the nursing responsibilities. Memory Jogger Common antidepressants used for pain management include: • amitriptyline • nortriptyline • paroxetine • sertraline 411 Anticonvulsants Anticonvulsants are drugs that work in the brain to reduce seizures. Some have been found to reduce neuropathic pain (nerve pain with tingling and burning) and migraine headaches. The two most common anticonvulsants used for pain management are gabapentin (Neurontin) and pregabalin (Lyrica). They appear to work by reducing the rate of pain signal transmission along sensory nerves and may also affect pain perception. The doses for pain management are often higher than those used to manage seizure disorders. Chapter 9 discusses the actions