Analgesics Pharmacology

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Questions and Answers

What is the primary action of salicylates such as Aspirin?

Antibiotic effect

Antiinflammatory, antiplatelet, and antipyretic effects (correct)

Hormonal regulation

Muscle relaxant properties

What should be monitored for a patient on salicylates?

Increase in magnesium levels

Decrease in sodium levels

Decrease in potassium levels (correct)

Increase in calcium levels

Which medication should not be taken in conjunction with salicylates?

Antibiotics

Other NSAIDs (correct)

Antidepressants

Antihypertensives

What risk is associated with the use of salicylates in children with flu or viral symptoms?

Reye syndrome Signup and view all the answers

Which of the following foods contains salicylates and may affect patients taking them?

Prunes Signup and view all the answers

What defines a non-opioid analgesic?

A medication that provides pain relief without altering consciousness Signup and view all the answers

Which type of pain commonly requires opioid medications for relief?

Visceral pain Signup and view all the answers

What term describes the amount of pain a person can endure without it interfering with normal function?

Pain tolerance Signup and view all the answers

Which of the following factors contributes to a lowered pain threshold?

Isolation Signup and view all the answers

Which of the following is a characteristic of somatic pain?

Originates from skeletal muscles, ligaments, or joints Signup and view all the answers

What is a common misconception regarding the treatment of pain?

All patients need strong opioids for pain relief Signup and view all the answers

Which statement best describes the genetic influence on pain sensitivity?

More µ receptors result in reduced pain sensitivity Signup and view all the answers

What percentage of patients are reported to experience unrelieved pain?

75% Signup and view all the answers

What is a potential outcome of unrelieved pain?

Hyperglycemia Signup and view all the answers

Which of the following is a side effect of acetaminophen?

Rash Signup and view all the answers

Which statement about non-opioid analgesics is true?

They can be used for treating mild to moderate pain. Signup and view all the answers

What is the primary mechanism by which strong opioid analgesics suppress cough?

Inhibiting the medullary cough center Signup and view all the answers

What is the maximum safe dosage of acetaminophen for adults in a 24-hour period?

4000 mg Signup and view all the answers

What is the term used for the practice of combining drugs to produce anesthesia?

Balanced anesthesia Signup and view all the answers

What should be monitored before and after administering acetaminophen?

Patient's pain level Signup and view all the answers

Which type of NSAID selectively inhibits COX-2?

Celecoxib Signup and view all the answers

Which of the following is NOT a common side effect of opioid analgesics?

Increased alertness Signup and view all the answers

What is an antidote for acetaminophen poisoning?

Acetylcysteine Signup and view all the answers

Which vital sign should be closely monitored when administering opioid analgesics?

Respirations Signup and view all the answers

What serious condition may result from opioid administration that is directly related to the degree of sedation?

Respiratory depression Signup and view all the answers

Inhibition of which cyclooxygenase (COX) can lead to kidney damage?

COX-1 Signup and view all the answers

Which opioid reversal agent may be needed in cases of severe respiratory depression?

Naloxone Signup and view all the answers

Which condition is NOT typically treated with non-opioid analgesics?

Severe migraine Signup and view all the answers

What effect can a patient's inability to describe pain have on their treatment?

It may result in undertreatment of pain. Signup and view all the answers

Histamine release is a side effect associated with which class of drugs?

Natural opioids Signup and view all the answers

What should be done if a patient’s respirations are found to be fewer than 12 breaths per minute after opioid administration?

Withhold the medication Signup and view all the answers

What is a primary therapeutic effect of ibuprofen?

To relieve mild pain and reduce fever Signup and view all the answers

Which patient should NOT receive ketorolac?

A patient allergic to NSAIDs Signup and view all the answers

What is an important administration consideration for ketorolac?

Therapy should not exceed 5 days Signup and view all the answers

What adverse effect is associated with the use of both ibuprofen and ketorolac?

GI bleed Signup and view all the answers

Which of the following is a common side effect of ibuprofen?

Dyspepsia Signup and view all the answers

What vital sign or lab test should be monitored for patients taking nonopioid analgesics like ibuprofen?

Liver function tests Signup and view all the answers

What symptom indicates the need to assess for a potential rash in a patient taking ibuprofen?

Skin rash or changes Signup and view all the answers

A patient has been prescribed ibuprofen and is experiencing nausea. What should be suggested?

Consume with food or milk if upset occurs Signup and view all the answers

What is a contraindication for administering ketorolac?

Renal failure Signup and view all the answers

What is the reason for assessing pain before and after administering nonopioid analgesics?

To evaluate the effectiveness of treatment Signup and view all the answers

Which opioid is approximately six times more potent than morphine?

Hydromorphone Signup and view all the answers

What is a major side effect of using opioid agonists, particularly hydrocodone?

Respiratory depression Signup and view all the answers

Which medication is considered a pure opioid antagonist?

Naloxone Signup and view all the answers

Which of the following is NOT a combination drug involving opioids?

Dilaudid Signup and view all the answers

What should be regularly assessed when using opioid medications due to their constipating effects?

Bowel function Signup and view all the answers

Which substance is primarily indicated for severe pain and can be administered via a transdermal patch?

Fentanyl Signup and view all the answers

What potential effect can naloxone have on a patient who is physically dependent on opioids?

Withdrawal symptoms Signup and view all the answers

Which of the following is an unlabeled use of opioids?

Diarrhea control Signup and view all the answers

Which opioid has fewer hypnotic effects compared to morphine?

Hydromorphone Signup and view all the answers

Which opioid should not be confused with hydromorphone due to its different properties?

Meperidine Signup and view all the answers

Study Notes

Analgesics

Analgesics are medications that relieve pain without causing loss of consciousness.
They are also known as painkillers.
Analgesics include opioid and non-opioid agents.

What is Pain?

Pain involves the actual sensation of pain from various nerve paths and the brain.
Pain threshold is the level of stimulus needed to produce the sensation of pain.
Pain perception is influenced genetically, with a μ (mu) opioid receptor gene influencing sensitivity. A higher number of μ receptors reduces pain sensitivity.
Pain tolerance is subjective and varies widely among people, being influenced by age, sex, culture, previous experiences with pain, and anxiety levels.

Visual Pain Scale

The Wong-Baker FACES Pain Rating Scale is a tool for assessing pain.
It uses faces to represent different levels of pain, ranging from no hurt (0) to worst hurt (10).

Conditions that Alter Pain Threshold

Lowered threshold: Conditions like anger, anxiety, depression, discomfort, fear, isolation, chronic pain, and sleeplessness and tiredness make pain more likely to be felt.
Raised threshold: Conditions like diversion, empathy, rest, and medications such as analgesics, anti-anxiety agents, and antidepressants make pain less likely to be felt.

Pain Persistence

Acute pain: Usually caused by obvious tissue damage, acts as a protective function, increases nervous system activity, and resolves upon healing.
Chronic pain: Pain that persists beyond the expected healing period. Pain no longer serves a helpful function and changes in pain signalling and detection occur, degrading health and function.

Sources of Pain

Somatic pain: Originates from skeletal muscles, ligaments, or joints, usually responds better to non-opioid medications (NSAIDs).
Visceral pain: Originates from organs or smooth muscles, usually requires opioids for relief.

Nursing Mnemonics for Pain & Symptoms

OLDCARTS: Onset, Location, Duration, Character, Alleviating & aggravating, Radiation, Time,Severity
SOCRATES: Site, Onset, Character, Radiation, Associated symptoms, Time/duration, Exacerbating & relieving, Severity
PQRST: Provoking, Quality, Region & radiation, Severity, Time

Undertreatment of Pain

Up to 75% of patients experience unrelieved pain.
Reasons for undertreatment include:
- Sociocultural variables
- Patient inability or unwillingness to describe their pain
- Lack of regular assessment
- Health care team attitudes
- Inaccurate knowledge concerning addiction/tolerance
Effects of unrelieved pain include increased heart rate, increased respiratory rate, increased blood pressure, increased stress response, urinary retention, and hyperglycemia.

WHO Ladder for Treatment of Pain

A tiered approach for pain management, progressing from non-opioid to opioid medication as needed. The ladder stages increase opioid strength.

Non-opioid Analgesics

Less potent than opioid analgesics.
Used to treat mild to moderate pain.
Effective for headaches, menstrual cramps, inflammation, minor injuries, and mild to moderate arthritis.
Examples include aspirin, ibuprofen, and acetaminophen.

Acetaminophen

Action: Inhibits prostaglandin synthesis.
Uses: Relieves pain, discomfort and fever.
Side effects: Rash, low incidence of GI distress.
Toxic effects/overdose: Hepatotoxicity, thrombocytopenia.

Salicylates (aspirin)

Action: Anti-inflammatory, antiplatelet, and antipyretic effects.
Therapeutic serum salicylate level: 15-30 mg/dL
Higher than 30 mg/dL: Toxic
Interactions with drugs: Increased bleeding with anticoagulants, hypoglycemia with oral antidiabetics, and increased gastric ulcer risk with glucocorticoids.
Labs: Increased Prothrombin Time (PT), bleeding time, INR. Also, decreased potassium, cholesterol, T3, and T4 levels.
Foods containing salicylates: Prunes, raisins, licorice, certain spices.
Caution: Do not take with other NSAIDs. Avoid during pregnancy. Do not give to children with flu or virus symptoms (Reye syndrome).

NSAIDS

Action: Inhibition of cyclooxygenase (COX)
1st Generation NSAIDS: Aspirin, Ibuprofen, Naproxen, Ketorolac, Indomethacin, Diclofenac, Meloxicam. Inhibit COX-1 and COX-2. Inhibition of COX-1 causes kidney damage and decreased platelet aggregation.
2nd Generation NSAID: Celecoxib. Inhibits COX-2 only.
Side effects and adverse reactions:
- Headache
- GI bleed
- Constipation
- Dyspepsia
- Nausea
- Vomiting
- Steven-Johnson syndrome
- Renal failure.

COX-1 and COX-2 Inhibitors

COX-1: Protects stomach lining, decreases fever, and promotes blood clotting.
COX-2: Triggers pain and inflammation.
Medications can either block COX-1 or COX-2 or both.

Oxicams

Piroxicam, Meloxicam
Indicated for long-term arthritic conditions
Can cause gastric problems, such as ulceration and epigastric distress
Should not be taken with aspirin or other NSAIDS

Selective COX-2 Inhibitors

Action: Selectively inhibits COX-2 enzyme without COX-1 inhibition.
Use: Decreases inflammation and pain.
Drug agents: Celecoxib
Similar Agents: Nabumetone

Opioid Analgesics

Opium obtained from the unripe seeds of the opium poppy, used for pain relief.

Common Opioid Analgesics

A table listing common opioid analgesics, their trade names, routes of administration, and typical adult dosages.

Opioid Analgesics: Mechanisms of Action

Opioids can be agonists, partial agonists, or antagonists.
Agonists bind with receptors and cause a response.
Partial agonists bind with receptors and cause only a limited response.
Antagonists bind with receptors and cause no effect; they will complete for binding sites with agonists.

Opioid Analgesics: Therapeutic Uses

Main use is to relieve moderate to severe pain.
Many have affinity for the CNS, suppressing the medullary cough center.
Often combined with other drugs for synergistic effect.

Opioid Analgesics: Therapeutic Uses (Continued)

Strong opioid analgesics, such as fentanyl, sufentanil, and alfentanil, are commonly used with anesthetics during surgery, with the combination practice being known as balanced anesthesia.

Side Effects

Central Nervous System: Sedation, disorientation, euphoria, lightheadedness, dysphoria, lowered seizure threshold, and tremors.
Cardiovascular: Hypotension, palpitations, and flushing
Respiratory: Respiratory depression, aggravation of asthma
GI: Nausea, vomiting, constipation, and biliary tract spasm
Other: Itching, rash, wheal formation, and urinary retention

Respiratory Depression

One of the most serious side effects of opioids; strongly related to the degree of sedation.
Careful titration may not prevent respiratory compromise. Assisted ventilation may be required.
Opioid reversal agents, such as naloxone (Narcan), may be necessary to reverse respiratory depression. Opioid antagonists also reverse pain control.

Vital Signs Monitoring

Monitor vital signs before, during, and after administration of opioid analgesics.
Withhold medication if respirations are less than 12 breaths per minute or if there are any changes in consciousness.

Release of Histamine

All opioids cause histamine release, more pronounced with natural opioids than synthetic ones.
Believed to be responsible for many unwanted side effects: itching, rash, hemodynamic changes (BP, pulse), and flushing.
Many patients misinterpret this as an allergic reaction, but true anaphylaxis is rare.

G.I. Side Effects

Opioids irritate the gastrointestinal tract, causing nausea, vomiting, and constipation.

Psychological Dependence (addiction)

A pattern of compulsive drug use characterized by continuous craving for an opioid and the need to take it for effects other than pain relief (e.g., euphoria).

Physical Dependence

Body's physiologic adaptation to the effects of an opioid.
Opioid tolerance: need for larger doses to achieve the same level of pain relief.
Expected in patients on long-term opioid treatment. This is distinct from psychological dependence.

Opioid Abstinence Syndrome

Physiologic response when an opioid agent is abruptly stopped or an opioid antagonist (such as naloxone) is administered.
Manifestations: Anxiety, irritability, chills, hot flashes, joint pain, lacrimation, rhinorrhea, diaphoresis, nausea, vomiting, abdominal cramping, diarrhea.

Stages of Opiate Withdrawal Syndrome

A series of stages (I-III) characterized by specific signs and symptoms, such as anxiety, drug craving, insomnia, GI disturbances, rhinorrhea (runny nose), mydriasis, diaphoresis (sweating), tachycardia, nausea/vomiting, hypertension, diarrhea, fever, chills, tremors, seizures, muscle spasms, and so on, typically presenting over a period of several hours to a few days after cessation of opioid use.

Opioid Interactions

Additive effects, including an increased risk of respiratory depression, can occur when opioids are combined with alcohol, antihistamines, barbiturates, benzodiazepines, MAO inhibitors, phenothiazines, and other CNS depressants.

Opioid Agonists

Morphine: C-II scheduled substance, used for severe pain, but is highly constipating. Usage should be done cautiously with head injury patients. Do not mistake with meperidine (Demerol).
Codeine: C-II scheduled substance for mild-moderate pain; less effective than morphine. Sometimes used as a cough suppressant.

Hydromorphone

Semi-synthetic opioid similar to morphine, six times more potent, with fewer hypnotic effects and less GI distress.

More Opioid Agonists

Fentanyl: C-II scheduled, very potent, used for moderate to severe pain and as an adjunct to general anesthesia. Various routes, including transdermal. Respiratory depression may last longer than analgesic effects and is more concerning.
Meperidine: C-II, synthetic opioid, used for moderate to severe pain, has risk of fatal reaction in patients receiving MAO inhibitors.

Fentanyl Overdoses

Illicit fentanyl is a major driver of synthetic opioid deaths in recent years. Its potency is 50-100x greater than morphine. The amount of fentanyl in the US has increased drastically in recent years.

Partial Opioid Agonists

Substances that bind to receptors and cause effects similar to pure agonists, but less pronounced.
Includes buprenorphine, butorphanol, dezocine, nalbuphine, and pentazocine

Naloxone (Narcan)

Pure opioid antagonist, no agonist properties.
Drug of choice for complete or partial reversal of opioid-induced respiratory depression.
Indicated for suspected acute opioid overdose and the diagnosis of opioid overdose.
Can precipitate opioid withdrawal in physically dependent patients.

Opioid Antagonists (Continued)

Side effects: Tremors, sweating, hypertension, tachycardia, excitement, nausea, vomiting, reversal of analgesia, dysrhythmias, and elevated PTT and bleeding.
Nursing interventions: Continuous monitoring of vital signs and bleeding.

Combination Drugs

Various opioid analgesics combined with other pain medications, such as NSAIDs and acetaminophen. Examples include hydrocodone and ibuprofen (Vicoprofen), hydrocodone and acetaminophen (Lortab, Vicodin), oxycodone and acetaminophen (Percocet), oxycodone and aspirin (Percodan), and acetaminophen and codeine (Tylenol #__) .

Transdermal Opioid Analgesics

Provide continuous, around-the-clock pain control, particularly helpful for patients with chronic pain.
Fentanyl (Duragesic): More potent than morphine; use caution with patients who weigh less than 110 pounds.

Analgesics in Special Populations

Analgesic use varies among children, older adults, cognitively-impaired individuals, oncology patients, and individuals with a history of substance abuse.

Adjuvant Therapies

Adjuvant therapy is often used along with non-opioid and opioid drugs.
Includes anticonvulsants, antidepressants, corticosteroids, antidysrhythmics, and local anesthetics.

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