Analgesic Drugs PDF

DRUGS AFFECTING THE NERVOUS SYSTEM AND ANAESTHESIA  outline 3. Drugs affecting the Nervous System: Analgesics: Opiates: morphine, pethidine, salicylates: aspirin, non-steroidal anti-inflammatory agents: Ibuprofen, miscellaneous: phenacetin, hypnotics (Sedatives): barbiturates e.g. pheno...

DRUGS AFFECTING THE NERVOUS SYSTEM AND ANAESTHESIA  outline 3. Drugs affecting the Nervous System: Analgesics: Opiates: morphine, pethidine, salicylates: aspirin, non-steroidal anti-inflammatory agents: Ibuprofen, miscellaneous: phenacetin, hypnotics (Sedatives): barbiturates e.g. phenobarb. 4. Anaesthetics: General anaesthetic agents: Inhalations e.g. nitrous oxide, halothane; intravenous e.g. thiopentone sodium. Local anaesthetic agents: Xylocaine. Drugs affecting the Nervous System Central nervous system agents are medicines that affect the central nervous system (CNS). The CNS is responsible for processing and controlling most of our bodily functions, and consists of the nerves in the brain and spinal cord. There are many different types of drugs that work on the CNS, including anesthetics, anticonvulsants, antiemetics, antiparkinson agents, CNS stimulants, muscle relaxants, narcotic analgesics (pain relievers), nonnarcotic analgesics (such as acetaminophen and NSAIDs), and sedatives.  ANALGESICS Analgesics are drugs used to relieve pain- “pain killers”. The two groups are: 1. Non-narcotic analgesics (for the mild to moderate pain, some of which may also have antipyretic actions) o Salicylates (aspirin, magnesium salicylate and sodium salicylate) oNon-salicylates (Paracetamol) oNSAIDS (Ibuprofen) 2. Narcotic/opioid analgesics (which are principally used in the relief of severe pain, and may produce dependence). E.g Morphine and Pethidine ANALGESICS Antipyretics are used in lowering the temperature, and is considered to involve the hypothalamus. Paracetamol, aspirin, and ibuprofen have similar antipyretic activity. Anti-inflammatory agents are drugs that alleviate symptoms of inflammation, but do not necessarily deal with the cause. E.g NSAIDS (Ibuprofen, Diclofenac, Indomethacin, Piroxicam) Non-narcotic analgesics ACETYLSALICYLIC ACID (ASPIRIN) DRUG SUMMARY: Acetylsalicylic Acid (ASA), Aspirin, is a salicylate that relieves headaches, muscular and joint pains, and reduces inflammation. ASA has been considered the drug of choice in the treatment of arthritis, but its anti-inflammatory action occurs only when given in large doses (3-4 g/day) ACETYLSALICYLIC ACID (ASPIRIN) The mechanism of action of ASA is that it inactivates cyclooxygenase irreversibly, it inhibits prostaglandin synthesis and inhibits platelet aggregation.  INDICATIONS: Relief of mild to moderate pain Fever Inflammatory conditions such as rheumatic fever, rheumatoid arthritis, osteoarthritis, dysmenorrhea and symptomatic relief of the common cold It is used for reducing the risk of recurrent Transient Ischemic Attacks (TIA/stroke), or Myocardial Infarctions (MI/heart attack) at low doses. DOSAGE FORMS: Tablets. RECOMMENDED DOSAGE: Adult: 350 - 650 mg q. 4 h. for minor aches and pain. 500 - 1000 mg q. 4-6 h.; max. 4 g/24 h., for moderate to severe pain. 75 - 325 mg/day q.d. continued indefinitely for: Ischemic stroke & TIA, and the prevention of recurrent MI, unstable angina pectoris, chronic stable angina pectoris. Child: Not recommended, unless for certain conditions. Salicylates can cause Reye's syndrome, a serious and sometimes fatal condition in children. ADVERSE EFFECTS: Dizziness cinchonism (ringing in the ear) skin eruptions epigastric discomfort Heartburns peptic ulceration and bleeding increase bleeding tendency hypersensitivity reactions Nausea Vomiting Anorexia  CONTRAINDICATIONS: In patients with history of hypersensitivity Asthma Peptic ulcer/dyspepsia Those with bleeding tendencies or disorders Late pregnancy (PPH, Prolong labour) DRUG INTERACTION Anticoagulants Anticoagulant effect enhanced. Effect of ASA on gastric mucosa and platelet function may enhance possibility of hemorrhage. Avoid concomitant use. NSAIDs Pharmacological effects of certain NSAIDs may be decreased. Increased risk of GI disturbances if used concomitantly. Oral hypoglycemic: ASA increases hypoglycemia effect of sulfonylureas. Monitor the patient’s blood glucose, if hypoglycemia occurs, decrease sulfonylurea TOXICITY (SYLICYLISM) Dizziness Tinnitus (a ringing sound in the ear) Impaired hearing Nausea Vomiting Flushing Sweating Rapid deep breathing Tachycardia Diarrhea Mental confusion Lassitude Drowsiness Respiratory depression and coma (large doses)  NURSING IMPLICATION 1. Take drug with or after food or with milk to decrease GI irritation. 2. Assess for history of asthma and history of hypersensitivity. 3. Do not use with other anticoagulants. 4. Note any history of peptic ulcer. 5. Report signs of side effect e.g. gastric irritation if occurs. 6. Aspirin is not given 1 week before & after surgery to prevent bleeding. 7. If patient is diabetic, discuss the possibility of hypoglycemia occurring and monitor their blood glucose level frequently. 8. Teach patient about the toxic symptoms (ringing in the ears dizziness, mental confusion etc and ask him/her to report it to physician.  PARACETAMOL = ACETAMINOPHEN (Doliprane®, Panadol®…) Non salicylate DRUG SUMMARY: Paracetamol or Acetaminophen (N-Acetyl-pamino-phenol-APAP) is a nonsalicylate, non-narcotic CNS agent. It relieves pain (analgesic)and reducing fever (antipyretic) It has no anti-inflammatory action. Paracetamol reduces fever by direct action on the hypothalamus heat- regulating center with consequent peripheral vaso-dilatation, sweating and dissipation of heat.  INDICATIONS: Used for pain and fever. Good substitute for aspirin, when aspirin is not tolerated or is contraindicated and also bleeding disorders CONTRAINDICATIONS: In patients with history of hypersensitivity. In patients with severe liver and kidney damage. DOSAGE FORMS: Tablets, capsules, suspension, suppositories and intravenous. RECOMMENDED DOSAGE: Adult: PO: 325-650 mg q. 4-6 h. as needed; max. 4 g/24 hours Child: PO or PR: 10-15 mg/kg/dose. AGE DOSE 0-3 month 10mg/kg (5mg/kg if jaundiced) 3 mon-1 y 60-120 mg 1-5 y 120-250 mg 6-12 y 250-500 mg ADVERSE EFFECTS: If used as directed it rarely causes any side effects. Heavy alcoholics and smokers are more susceptible to liver toxicity. Skin rashes and neutropenia are very rare. DRUG INTERACTIONS: Alcohol Barbiturates Carbamazepine Rifampicin The potential hepatotoxicity of Paracetamol may be increased by large doses or long term leading to destruction of the liver cells TOXICITY Signs of acute acetaminophen toxicity include the following: Nausea Vomiting Confusion Liver tenderness Hypotension Arrhythmias Jaundice Acute hepatic and renal failure NURSING IMPLEMENTATION The nurse administers acetaminophen with a full glass of water. The patient may take this drug with meals or on an empty stomach. Symptoms of overdosage include nausea, vomiting, diaphoresis, and generalized malaise. Acute overdosage may be treated with the administration of the drug acetylcysteine (Mucomyst) to prevent liver damage Monitor toxicity level( 100 and 300 mcg/mL) NON-STEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS) The NSAIDs are another type of nonnarcotic analgesic. All NSAIDs are antipyretic, analgesic, and anti-inflammatory, but there might be some differences in their individual activities. NSAIDS are usually effective against pain of low-to moderate intensity. Although their maximal effect is much lower than opioids, they lack the unwanted effects of the opioids on the CNS, including respiratory depression and the development of physical dependence.  ACTION The NSAIDs are so named because they do not belong to the steroid group of drugs Do not possess the adverse reactions of the steroids Although the exact mechanisms of actions are not known, the NSAIDs are thought to act by o inhibiting prostaglandin (a group of naturally occurring fatty acids that act within the body to regulate acid secretion of the stomach, regulate body temperature and platelet aggregation, and control inflammation) o synthesis by inhibiting the action of the enzyme cyclooxygenase, the enzyme responsible for prostaglandin synthesis.  ACTION The NSAIDs act to inhibit the activity of two related enzymes: 1. cycloo1xygenase-1 (COX-1), the enzyme that helps to maintain the stomach lining. 2. cyclooxygenase-2 (COX-2), the enzyme that triggers pain and inflammation. The anti-inflammatory effects of the NSAIDs are carried out by inhibition of COX-2. The gastrointestinal adverse reactions are caused by inhibition of COX-1 The newer NSAIDs (celecoxib and rofecoxib) appear to work by specifically inhibiting the COX-2 enzyme, without inhibiting the COX-1 enzyme. Celecoxib and rofecoxib relieve pain and inflammation with less potential for gastrointestinal adverse  NDAIDS CLASSIFICATION Non Selective Cox Inhibitor Selective Cox 2 inhibitors Salicylic acid derivatives (aspirin) Nimesulidde Para aminophenol derivatives (paracetamol) Pyrazolone derivatives (Sphenylbutazone) Celecoxib Indole acetic derivative (sulidac rofecoxib Arylacetic acid derivative (diclofenac Proprionic acid derivatives (Ibuprofen) Anthralinic acid derivatives (Flufenamic acid) Oxicams (piroxicam) Alkanones (nabumetone)  INDICATION Relief of signs and symptoms of osteoarthritis, rheumatoid arthritis, and other musculoskeletal Mild to moderate pain relief Primary dysmenorrhea Fever reduction  ADVERSE EFFECT Many adverse reactions are associated with the use of the NSAIDs. However, many patients take these drugs and experience few, if any, side effects. Gastrointestinal tract—nausea, vomiting, diarrhea, constipation, epigastric pain, indigestion, abdominal distress or discomfort, intestinal ulceration, stomatitis, jaundice, bloating, anorexia, and dry mouth Central nervous system—dizziness, anxiety, lightheadedness, vertigo, headache, drowsiness, insomnia, confusion, depression, and psychic disturbances Cardiovascular—congestive heart failure, decrease or increase in blood pressure, and cardiac arrhythmias Renal—hematuria, cystitis, elevated blood urea nitrogen, polyuria, dysuria, oliguria, and acute renal failure in those with impaired renal function Special senses—visual disturbances, blurred or diminished vision, diplopia, swollen or irritated eyes, photophobia, reversible loss of color vision, tinnitus, taste change, and rhinitis  CONTRAINDICATIONS/DRUG INTERACTION The NSAIDs are contraindicated in patients with known hypersensitivity. There is a cross- sensitivity to other NSAIDs. Therefore, if a patient is allergic to one NSAID, there is an increased risk of an allergic reaction with any other NSAID. Hypersensitivity to aspirin is a contraindication for all NSAIDs. In general, the NSAIDs are contraindicated during the third trimester of pregnancy and during lactation. The NSAIDs are used cautiously in patients with bleeding disorders, renal disease, cardiovascular disease, or hepatic impairment and in the elderly. There is an increased risk of ulcer formation in patients older than 65 years. The NSAIDs prolong bleeding time and increase the effects of anticoagulants, lithium, cyclosporine, and the hydantoins. These drugs may decrease the effects of diuretics or antihypertensive drugs. Long-term use of the NSAIDs with acetaminophen may increase the risk of renal impairment.  IBUPROFEN Ibuprofen (IBP) is a proprionic acid derivative comparable to aspirin (ASA) in its analgesic action, but higher doses are required for anti-inflammatory effect. It has less GI symptoms than aspirin in equi-effective doses. IBP inhibits platelet aggregation and prolongs bleeding time, but does not affect prothrombin or whole blood clotting times. INDICATION: Rheumatoid arthritis (RA), Osteoarthritis (OA) and Ankylosing spondylitis CONTRAINDICATIONS: In patients who are hypersensitive where urticaria, severe rhinitis, bronchospasm, angioedema, are precipitated by ASA or other NSAIDs. Active peptic ulcer or bleeding abnormalities. DOSAGE FORMS: Tablets, suspension, IM, IV, gel 5%. RECOMMENDED DOSAGE: Adult: 200-400 mg PO q. 4-6 h., max. 1800 mg/24 hours for pain and fever. 400- 800 mg t.i.d. or q.i.d.; max. 3200 mg/d for inflammation. Emulgel dose: A thin layer of the gel is applied to affected area as needed, up to three times daily. Child: Use is not recommended for children under 6 months DOSES OF IBP IN CHILDREN 1-12 y: give 5-10 mg/kg q. 4-6 h. Maximum daily dose is 40 mg/kg/d.  ADVERSE EFFECTS: GI disturbances are most common; i.e. Heartburn nausea dyspepsia abdominal distress gastritis and ulceration Also, dizziness, drowsiness, jaundice, and fatigue may occur. Side effects are dose related. DRUG INTERACTIONS: Oral anticoagulants, and heparin: May prolong bleeding time. Avoid concomitant use. Lithium, digoxin and methotrexate: Increased toxicity of these drugs with concomitant NSAIDs use. Monitor each drug serum levels and adjust dose as needed.  NURSING IMPLICATION i. Patients with history of cardiac decompensation should be observed closely for evidence of fluid retention and edema. ii. Instruct patient to report immediately any passage of dark tarry stool, coffee- ground emesis, blood or protein in urine. This can be an indication for GI bleeding. Medication should be stopped and patient should be re-evaluated. iii. Caution if skin rash, itching, visual disturbances or persistent headache should occur. iv. Caution in hypertension, chronic renal failure. v. Advise patient not to drink alcohol, to avoid increased risk of GI ulceration and bleeding.  DICLOFENAC An acetic acid derivative. It has analgesic, antipyretic, and anti-inflammatory properties. At therapeutic doses it has little effect on platelet aggregation. Patients not responding to IBP can be given diclofenac instead. INDICATION: Rheumatoid arthritis (RA), Osteoarthritis (OA), Ankylosing spondylitis. It is also used as an ophthalmic agent for cataract surgery). CONTRAINDICATION: Same as IBP. DOSAGE FORMS: Tablets, sustained release tablets, suppositories, emulgel and ampoules.  RECOMMENDED DOSAGE: Adult: 75-150 mg/24h given by mouth in divided doses. Total daily dose should not exceed 150 mg/d, such doses have not been studied. Suppository form is given in a dose of 75- 100 mg each evening. The emulgel form 1% should be applied to painful site, 2-4 gm, 3-4 times daily. Therapy should be reviewed after 14 days. Child: Not recommended for children < 1 year Child > 1 year for RA: 1-3 mg/kg in divided doses by mouth or rectum. ADVERSE EFFECTS: Similar to IBP, but with higher incidence.  DRUG INTERACTIONS: Lithium, digoxin and methotrexate Increased toxicity of these drugs with concomitant NSAIDs use. Diuretics May decrease blood pressure lowering effects of diuretics. May lead to an increase in serum K+, if using K+ sparing diuretics. NURSING IMPLICATION Monitor each drug serum levels and adjust dose as needed. Same as IBP. Assignment Celecoxib Rofecoxib Narcotic/opioid analgesics  Opioid analgesics Opioid analgesics are the narcotic analgesics obtained from the opium plant. Raw narcotics: morphine, codeine, hydrochlorides of opium alkaloids, and camphorated tincture of opium. Semisynthetic narcotics: Morphine: hydromorphone, oxymorphone, oxycodone, and heroin. Synthetic narcotics: analgesics: methadone, levorphanol, remifen  ACTION Narcotic analgesics are classified as agonists, partial agonists, and mixed agonists-antagonists. The agonist binds to a receptor and causes a response. A partial agonist binds to a receptor, but the response is limited (ie, is not as great as with the agonist). Antagonists bind to a receptor and cause no response. An antagonist can reverse the effects of the agonist. This reversal is possible because the antagonist competes with the agonist for a receptor site  ACTION Classification of the narcotic analgesics is based on their activity at the opioid receptor sites Only three of these receptors affect the action of the narcotic analgesics: mu kappa delta  Three receptors mediate the effects of opiates: 1. MU receptors analgesic and unwanted effect 2. Delta receptors for peripheral effects 3. Kappa receptors contribute to analgesia at the spinal, may act only on calcium channels  INDICATION 1. Relieve or manage moderate to severe acute and chronic pain. The ability of a narcotic analgesic to relieve pain depends on several factors, such as the drug, the dose, the route of administration, the type of pain, the patient, and the length of time the drug has been administered 2.To lessen anxiety and sedate the patient before surgery. Patients who are relaxed and sedated when anesthesia is given are easier to anesthetize (less dose) as well as easier to maintain under anesthesia 3. Support of anesthesia (ie, as an adjunct during anesthesia) 4. Obstetrical analgesia 5. Relief of anxiety in patients with dyspnea associated with pulmonary edema  INDICATION Intrathecally or epidurally for pain relief for extended periods without apparent loss of motor, sensory, or sympathetic function Relief of pain associated with a myocardial infarction (morphine) Management of opiate dependence (levomethadyl) Detoxification of and temporary maintenance of narcotic addiction (methadone) To induce conscious sedation before a diagnostic or therapeutic procedure in the hospital setting Treatment of severe diarrhea and intestinal cramping (camphorated tincture of opium) Relief of severe, persistent cough (codeine, although the drug’s use has declined)  ADVERSE REACTIONS The adverse reactions differ according to whether the narcotic analgesic acts as an agonist or as an agonist-antagonist. Agonists Major hazards of narcotic administration is respiratory depression, with a decrease in the respiratory rate and depth. Others: light-headedness, dizziness, sedation, constipation, anorexia, nausea, vomiting, and sweating.  ADVERSE REACTIONS Others: Central nervous system—euphoria, weakness, headache, pinpoint pupils, insomnia, agitation, tremor, and impairment of mental and physical tasks Gastrointestinal—dry mouth and biliary tract spasms Cardiovascular—flushing of the face, peripheral circulatory collapse, tachycardia, bradycardia, and palpitations Genitourinary—spasms of the ureters and bladder sphincter, urinary retention or hesitancy Allergic—pruritus, rash, and urticaria Other—physical dependence, pain at injection site, and local tissue irritation  ADVERSE REACTIONS Agonist-Antagonists Administration of a narcotic agonist-antagonist may result in symptoms of narcotic withdrawal in those addicted to narcotics. Other adverse reactions include: Sedation Nausea Vomiting Sweating Headache Vertigo Dry Mouth Euphoria Dizziness.  CONTRAINDICATIONS Hypersensitivity to the drugs. Acute bronchial asthma, emphysema, or upper airway obstruction and in patients with head injury or increased intracranial pressure. Patients with convulsive disorders, severe renal or hepatic dysfunction, acute ulcerative colitis. The narcotic analgesics are not recommended for use during pregnancy or labor (may prolong labor or cause respiration depression of the neonate). The use of narcotic analgesics is recommended during pregnancy only if the benefit to the mother outweighs the potential harm to the fetus.  PRECAUTION These drugs are used cautiously in the elderly Patients with undiagnosed abdominal pain, liver disease, history of addiction to the opioids, hypoxia, supraventricular tachycardia, prostatic hypertrophy, and renal or hepatic impairment. The obese must be monitored closely for respiratory depression while taking the narcotic analgesics. The drug is used cautiously during lactation (wait at least 4 to 6 hours after taking the drug to breastfeed the infant). The narcotics are used cautiously in patients undergoing biliary surgery because the drug may cause spasm of the sphincter of Oddi. DRUG INTERACTION The narcotic analgesics potentiate the central nervous system (CNS) depressant properties of other CNS depressants, such as Alcohol Antihistamines Antidepressants, Sedatives Phenothiazines Monoamine Oxidase Inhibitors.  NURSE IMPLICATION Assess pain and drug allergy Check vital signs 20 to 30 minutes after the drug is administered intramuscularly or subcutaneously, 30 or more minutes if the drug is given orally, and in 5 to 10 minutes if the drug is given intravenously Observe for respiratory depression Monitor patient for constipation Most patients should begin taking a stool softener or laxative with the initial dose of a narcotic analgesic The nurse assesses food intake after each meal (prolong intake causes anorexia). NARCOTIC ANTAGONIST An antagonist is a substance that counteracts the action of something else. A drug that is an antagonist has an affinity for a cell receptor, and by binding to it, prevents the cell from responding. Thus, a narcotic antagonist reverses the actions of a narcotic. Specific antagonists have been developed to reverse the respiratory depression associated with the opiates. The two narcotic antagonists in use today are naloxone (Narcan) and naltrexone Presentation Pethidine Tramadol Morphine Sedative/hypnotics Sedative/hypnotics A sedative is a drug that produces a relaxing, calming effect. Sedatives are usually given during daytime hours, and although they may make the patient drowsy, they usually do not produce sleep. A hypnotic is a drug that induces sleep, that is, it allows the patient to fall asleep and stay asleep  CLASSIFICATION Sedatives and hypnotics may be divided into two classes: o barbiturates o miscellaneous sedatives and hypnotics. The barbiturates are divided into several groups, depending on their duration of action: Ultrashort-acting (eg, thiamylal [Surital], thiopental [Pentothal]). The ultrashort-acting barbiturates are used as anesthetics. Single doses have a duration of 20 minutes or less. Short-acting (eg, secobarbital [Seconal], pentobarbital [Nembutal]). The average duration of action of the short-acting barbiturates is 3 to 4 hours. Intermediate-acting (eg, amobarbital [Amytal], aprobarbital [Alurate], butabarbital [Butisol]). The average duration of action of the intermediate-acting barbiturates is 6 to 8 hours. Long-acting (eg, phenobarbital, mephobarbital [Mebaral]). The average duration of action of the long-acting barbiturates is 10 to 16 hours. CLASSIFICATION The miscellaneous sedatives and hypnotics consist of a group of nonrelated drugs and a second group called the benzodiazepines. Examples of the nonrelated group of drugs include ethchlorvynol (Placidyl), zaleplon (Sonata), and zolpidem (Ambien). The benzodiazepines are also called antianxiety drugs Examples of the benzodiazepines include estazolam (ProSom), flurazepam (Dalmane), and quazepam (Doral).  Barbiturates All barbiturates have essentially the same mode of action. Depending on the dose given, these drugs are capable of producing:  Central nervous system (CNS) depression  Mood alteration ranging from mild excitation to mild sedation  Hypnosis (sleep), and deep coma.  Respiratory depressants  Miscellaneous or nonbarbiturate sedatives Miscellaneous or nonbarbiturate sedatives and hypnotics have essentially the same mode of action as the barbiturates Depress the CNS Have a lesser effect on the respiratory rate  ADVERSE REACTION Barbiturates Adverse reactions associated with barbiturate administration include: CNS—somnolence, agitation, confusion, CNS depression, ataxia, nightmares, lethargy, residual sedation (drug hangover), hallucinations, paradoxical excitement Respiratory—hypoventilation, apnea, respiratory depression, bronchospasm, laryngospasm Gastrointestinal—nausea, vomiting, constipation, diarrhea, epigastric pain Cardiovascular—bradycardia, hypotension, syncope Hypersensitivity—rash, angioneurotic edema, fever, urticaria Other—headache and liver damage  ADVERSE REACTION Miscellaneous Sedatives and Hypnotics Common adverse reactions include: Dizziness Drowsiness Headache Nausea. CONTRAINDICATIONS Hypersensitivity to the sedatives or hypnotics Comatose patients Severe respiratory problems History of drug and alcohol abuse Pregnant or lactating women. Drug interaction The sedatives and hypnotics have an additive effect when administered with Alcohol antidepressants narcotic Analgesics antihistamines phenothiazines. NURSE IMPLICATION Check baseline vital signs Monitor sleep pattern Assess fall risk and prevent falls Assess for drowsiness, headache and confusion Assist patient with ambulation, standing and activity of daily living Monitor for dependency Advice patient not to drink any alcoholic beverage 2 hours before, with, or 8 hours after taking the drug Advice patient not use over-the-counter (OTC) cold, cough, or allergy drugs while taking this drug unless their use has been approved by the primary health care provider. ANAESTHESIA  Anesthesia Anesthesia is a loss of feeling or sensation TYPES 1. Local anesthesia (specific area or region), Person is awake or partially sedated but no pain 2. General anesthesia is the provision of a pain-free state for the entire body, loss of consciousness, lost of reflexes such as the swallowing and gag reflexes LOCAL ANAESTHESIA ADMINISTRATION Topical application Local infiltration Regional anesthesia. Topical Anaesthesia Topical anesthesia involves the application of the anesthetic to the surface of the skin, open area, or mucous membrane. The anesthetic may be applied with a cotton swab or sprayed on the area. Local Infiltration Anesthesia Local infiltration anesthesia is the injection of a local anesthetic drug into tissues. This type of anesthesia may be used for dental procedures, the suturing of small wounds, or making an incision into a small area (biopsy)  Regional Anesthesia Regional anesthesia is the injection of a local anesthetic around nerves so that the area supplied by these nerves will not send pain signals to the brain. The anesthetized area is usually larger than the area affected TYPES Spinal anesthesia Conduction blocks  Regional Anesthesia Spinal Anesthesia Spinal anesthesia is a type of regional anesthesia that involves the injection of a local anesthetic drug into the subarachnoid space of the spinal cord, usually at the level of the second lumbar vertebra. There is a loss of feeling (anesthesia) and movement in the lower extremities, lower abdomen, and perineum. Conduction Blocks A conduction block is a type of regional anesthesia produced by injection of a local anesthetic drug into or near a nerve trunk. Example: epidural block (injection of a local anesthetic into the space surrounding the dura of the spinal cord) OBG transsacral (caudal) block (injection of a local anesthetic into the epidural space at the level of the sacrococcygeal notch); brachial plexus block (injection of a local anesthetic into the brachial plexus) arms. EXAMPLE OF LOCAL ANAESTHESIA GENERIC NAME TRADE NAME articaine HCl Septocaine bupivacaine HCl Marcaine HCl, generic chloroprocaine HCl Nesacaine, Nescaine-MPF lidocaine HCl Dilocaine, Xylocaine, generic mepivacaine HCl Carbocaine, Isocaine HCl prilocaine HCl Citanest HCl procaine HCl Novocain, generic Ropivacaine Naropin tetracaine HCl Pontocaine HCl PREANESTHETIA A preanesthetic drug is a drug given before the administration of anesthesia. The nurse usually gives a preanesthetic drug but on occasion may give it before injection of the local anesthetic to sedate the patient.  Purpose of Preanesthetic Drugs The general purpose of the preanesthetic drug is to prepare the patient for anesthesia. The more specific purposes of these drugs include the following: 1. Narcotic or antianxiety drug—to decrease anxiety and apprehension immediately before surgery. The patient who is calm and relaxed can be anesthetized 2. Cholinergic blocking drug—to decrease secretions of the upper respiratory tract. Some anesthetic gases and volatile liquids are irritating to the lining of the respiratory tract and thereby increase mucous secretions. 3. Antiemetic—to lessen the incidence of nausea and vomiting during the immediate postoperative recovery period EXAMPLES OF PREANAESTHESIA DRUGS GENERIC NAME TRADE NAME* Narcotics Droperido Inapsine fentanyl Sublimaze, generic meperidine hydrochloride Demerol, generic morphine sulfate Duramorph, generic Barbiturates Pentobarbital Nembutal Sodium, generic Secobarbital generic Cholinergic-Blocking Drugs atropine sulfate generic glycopyrrolate Robinul, generic scopolamine generic Antianxiety Drugs With Antiemetic Properties hydroxyzine Atarax, Vistaril, generic Antianxiety Drugs Chlordiazepoxide Librium, generic diazepam Valium, generic Midazolam Versed  GENERAL ANAESTHESIA The administration of general anesthesia requires the use of one or more drugs. The choice of anesthetic drug depends on many factors, including: The general physical condition of the patient The area, organ, or system being operated on The anticipated length of the surgical procedure General anesthesia is most commonly achieved when the anesthetic vapors are inhaled or administered intravenously (IV). Volatile liquid anesthetics produce anesthesia when their vapors are inhaled. Examples of volatile liquids include halothane, desflurane, and enflurane. Gas anesthetics are combined with oxygen and administered by inhalation. Examples of gas anesthetics are nitrous oxide and cyclopropane.  Stages of General Anesthesia General surgical anesthesia is divided into the following stages: Stage I—analgesia Stage II—delirium Stage III—surgical analgesia Stage IV—respiratory paralysis STAGE I Induction is a part of stage I anesthesia. It begins with the administration of an anesthetic drug and lasts until consciousness is lost. With some induction drugs, such as the short-acting barbiturates, this stage may last only 5 to 10 seconds. STAGE II Stage II is the stage of delirium and excitement. This stage is also brief. During this stage, the patient may move about and mumble incoherently. The muscles are somewhat rigid, and the patient is unconscious and cannot feel pain. During this stage, noises are exaggerated and even quiet sounds may seem extremely loud to the patient. If surgery were attempted at this stage, there would be a physical reaction to painful stimuli, yet the patient would not remember sensing pain. During these first two stages of anesthesia, the nurse and other health care professionals avoid any unnecessary noise or motion. STAGE III Stage III is the stage of surgical analgesia and is divided into four parts, planes, or substages. The anesthesiologist differentiates these planes by the character of the respirations, eye movements, certain reflexes, pupil size, and other factors. The levels of the planes range from plane 1 (light) to plane 4 (deep). At plane 2 or 3, the patient is usually ready for the surgical procedure. STAGE IV Stage IV is the stage of respiratory paralysis and is a rare and dangerous stage of anesthesia. At this stage, respiratory arrest and cessation of all vital signs may occur. Nursing Responsibilities During the Administration of General Anesthesia Preanesthesia Before surgery, the nurse has the following responsibilities: Performing the required tasks and procedures as prescribed by the physician and hospital policy the day or evening before or the morning of surgery and recording these tasks on the patient’s chart. Examples of these tasks include administration of a hypnotic the night before surgery, shaving the operative area, taking vital signs, seeing that the operative consent is signed, checking to see if all jewelry or metal objects are removed, administering enemas, inserting a catheter, inserting a nasogastric tube, and teaching. Checking the chart for any recent, abnormal laboratory tests. If a recent, abnormal laboratory test was attached to the patient’s chart shortly before surgery, the nurse must make sure that the surgeon and the anesthesiologist are aware of the abnormality. The nurse can attach a note to the front of the chart and contact the surgeon or anesthesiologist by telephone. Nursing Responsibilities During the Administration of General Anesthesia Placing a list of known or suspected drug allergies or idiosyncrasies on the front of the chart. Administering the preanesthetic (preoperative) drug. Instructing the patient to remain in bed and placing the side rails up once the preanesthetic drug has been given. Postanesthesia: Recovery Room After surgery, the nurse has the following responsibilities, which vary according to where the nurse first sees the postoperative patient: Admitting the patient to the unit according to hospital procedure or policy. Checking the airway for patency, assessing the respiratory status, and giving oxygen as needed. Postanesthesia: Recovery Room Positioning the patient to prevent aspiration of vomitus and secretions. Checking blood pressure, pulse, intravenous lines, catheters, drainage tubes, surgical dressings, and casts. Reviewing the patient’s surgical and anesthesia records. Monitoring the blood pressure, pulse, and respiratory rate every 5 to 15 minutes until the patient is discharged from the area. Checking the patient every 5 to 15 minutes for emergence from anesthesia. Suctioning is provided as needed.  Postanesthesia: Recovery Room Exercising caution in administering narcotics. The nurse must check the patient’s respiratory rate, blood pressure, and pulse before these drugs are given and 20 to 30 minutes after administration The physician is contacted if the respiratory rate is below 10 before the drug is given or if the respirations fall below 10 after the drug is given. Discharging the patient from the area to his or her room or other specified area. The nurse must record all drugs administered and nursing tasks performed before the patient leaves the postanesthesia recovery room.