Pharmacology Midterm Study Guide PDF

Pharmacology Study Guide Scheduled drugs: DEFINITIONS: Absorption Definition: The process by which a drug moves from its site of administration into the bloodstream. Example: Oral medications are absorbed in the gastrointestinal tract before entering the blood. Advers...

Pharmacology Study Guide Scheduled drugs: DEFINITIONS: Absorption Definition: The process by which a drug moves from its site of administration into the bloodstream. Example: Oral medications are absorbed in the gastrointestinal tract before entering the blood. Adverse Effects Definition: Unintended and potentially harmful effects caused by a drug at normal doses. Example: Nausea and dizziness caused by some antibiotics. Agonists Definition: Substances that bind to receptors and activate them to produce a biological response. Example: Morphine is an opioid agonist that activates receptors to relieve pain. Antagonists Definition: Substances that bind to receptors but do not activate them, blocking the action of agonists. Example: Naloxone is an opioid antagonist that reverses opioid overdose. Bioavailability Definition: The proportion of a drug that enters the bloodstream in its active form after administration and becomes available for use by the body. Example: Intravenous drugs have 100% bioavailability. Biotechnology Definition: The use of biological processes, organisms, or systems to develop medical products and treatments. Example: The production of insulin using recombinant DNA technology. Biotransformation Definition: The chemical modification of a drug within the body, often by the liver, to make it easier to excrete. Example: Conversion of codeine into its active form, morphine. Bolus Doses Definition: A single, large dose of a drug administered rapidly, typically intravenously. Example: A bolus dose of antibiotics given to treat severe infections. Idiosyncratic Effects Definition: Rare and unpredictable drug reactions that occur in some individuals due to genetic differences or unknown factors. Example: Severe skin reactions to penicillin in some patients. Indications Definition: The medical conditions or symptoms for which a drug is approved and intended to treat. Example: The indication for acetaminophen is pain and fever relief. Metabolism Definition: The process by which the body breaks down drugs, usually in the liver, into active or inactive compounds.  Example: Paracetamol is metabolized in the liver into non-toxic byproducts. Parenteral Administration Definition: Delivering drugs by injection, bypassing the gastrointestinal tract. Routes: Intravenous (IV), intramuscular (IM), subcutaneous (SC). Example: Insulin is often given via subcutaneous injection. Pharmacodynamics Definition: The study of how a drug affects the body, including the mechanisms of action and effects on tissues and organs. Example: The effect of beta-blockers on reducing heart rate. Pharmacokinetics Definition: The study of how the body absorbs, distributes, metabolizes, and eliminates a drug. Example: Tracking the half-life of a medication to determine dosing intervals. Plasma Protein Binding Definition: The degree to which a drug binds to proteins (e.g., albumin) in the blood. Only the unbound drug is active and able to exert an effect. Example: Warfarin is highly plasma protein-bound, meaning only a small amount is active at any given time. Reconstitution Definition: The process of mixing a powdered drug with a liquid (diluent) to prepare it for administration. Example: Reconstituting powdered antibiotics with sterile water before injection. In Canada, the National Drug Schedules (NDS) classify drugs into categories based on how they are accessed and dispensed. These schedules are intended to promote safe medication use while balancing access. Here's an overview: Schedule I: Prescription-Only Drugs Description: Medications that require a prescription from a licensed healthcare professional. Examples: o Antibiotics (e.g., amoxicillin) o Controlled substances (e.g., opioids like morphine) o Antidepressants (e.g., fluoxetine) o Blood pressure medications (e.g., lisinopril) Schedule II: Behind-the-Counter Drugs Description: Medications that are available without a prescription but must be dispensed by a pharmacist. These are stored behind the pharmacy counter and require consultation with the pharmacist for safe use. Examples: o Insulin (some types) o Emergency contraception (e.g., Plan B) o High-dose ibuprofen (e.g., 400 mg or higher) Schedule III: Over-the-Counter Drugs Description: Medications available for self-selection in the pharmacy but under pharmacist supervision. Examples: o Low-dose acetaminophen with codeine o Low-dose iron supplements o Some antihistamines (e.g., loratadine) Unscheduled: General Sales Description: Medications that can be sold without pharmacist supervision and are available in various retail settings like grocery stores, convenience stores, or gas stations. Examples:  o Basic pain relievers (e.g., acetaminophen, ibuprofen at low doses) o Cough syrups without codeine o Vitamin and mineral supplements Controlled Drugs and Substances Act (CDSA) In addition to the National Drug Schedules, controlled substances are regulated under the CDSA and are divided into Schedules I to VIII, with Schedule I being the most strictly controlled. These include: Schedule I: Most dangerous drugs (e.g., opioids like heroin, fentanyl) Schedule II: Cannabis (now regulated under the Cannabis Act) Schedule III: Psychedelics (e.g., LSD, mescaline) Schedule IV: Therapeutic drugs (e.g., benzodiazepines) Schedule V to VIII: Lesser-controlled substances General Concepts Routes of Administration Oral (GI tract): Absorbed through the stomach and intestines. May face first-pass metabolism in the liver, reducing bioavailability. Parenteral: Bypasses the GI tract for direct absorption into the bloodstream. o Examples: Intravenous (IV), intramuscular (IM), subcutaneous (SC). o IV has 100% bioavailability. Topical: Applied directly to skin, eyes, ears, nasal passages, or lungs for localized effects. Sublingual/Buccal: Rapid absorption into systemic circulation through mucosal membranes, bypassing first-pass metabolism. Inhalation: Rapid delivery of medication to lungs for systemic or local effects. Pharmacokinetics Absorption: Process by which the drug enters the bloodstream. o Factors: Route, solubility, pH, blood flow. Distribution: Transportation of drugs to tissues. o Fat-soluble drugs: Easily cross cell membranes, including the blood-brain barrier. o Water-soluble drugs: Restricted to aqueous compartments. o Protein binding: Only free drugs are active. Metabolism: Chemical modification of drugs, primarily in the liver (cytochrome P450 enzymes). o Phase I: Oxidation, reduction, hydrolysis. o Phase II: Conjugation for water solubility. Excretion: Elimination via kidneys (urine), liver (bile), lungs, or sweat. o Renal function is critical for drug clearance. Therapeutic Concepts  Therapeutic Index (TI): Ratio between the toxic dose and effective dose. o Narrow TI: Requires close monitoring (e.g., warfarin, digoxin). Half-Life: Time required for plasma concentration to reduce by half. o Determines dosing intervals. Peak and Trough Levels: o Peak: Highest drug concentration. o Trough: Lowest drug concentration before next dose. Adverse Effects: o Toxicity: Harmful levels in the body. o Allergic Reactions: Immune-mediated response (e.g., anaphylaxis). o Idiosyncratic Reactions: Unpredictable, unique to the individual. Unit 1: Federal and Provincial Legislation and Standards Related to Medication and Nursing Practice Federal Legislation: o Controlled Drugs and Substances Act (CDSA): Regulates the possession, sale, distribution, and use of controlled substances. o Food and Drugs Act (FDA): Ensures safety, efficacy, and proper labeling of drugs in Canada. o Cannabis Act: Regulates the use and access to medical and recreational cannabis. o Narcotic Control Regulations: Govern prescribing, dispensing, and handling of narcotics. Provincial Legislation (Varies by Province): o Provincial nursing regulatory bodies (e.g., College of Licensed Practical Nurses of Alberta) set standards for medication administration. o Regulations define LPN scope of practice, such as administering specific types of medications or performing independent medication administration. Purpose of Medications in Maintaining or Promoting Health Prevent Disease: Vaccines prevent infectious diseases. Treat Illnesses: Antibiotics treat bacterial infections. Manage Chronic Conditions: Insulin controls diabetes; antihypertensives manage high blood pressure. Relieve Symptoms: Analgesics manage pain; antihistamines alleviate allergies. Promote Health: Nutritional supplements, such as vitamins, prevent deficiencies. Differentiation Among Chemical, Trade, and Generic Names Chemical Name: The drug’s molecular structure (e.g., N-acetyl-para-aminophenol). Generic Name: The official name approved by regulatory agencies (e.g., acetaminophen). Trade Name: The brand name created by manufacturers (e.g., Tylenol). Differentiation Among Prescription, Controlled, Non-Prescription, and Herbal Medications Prescription: Require a healthcare provider’s authorization (e.g., antibiotics like amoxicillin). Controlled: Strictly regulated due to potential for abuse (e.g., opioids like morphine). Non-Prescription (OTC): Can be purchased without a prescription (e.g., ibuprofen). Herbal: Plant-derived products used for health purposes (e.g., echinacea). FDA Pregnancy Safety Categories 1. Category A: Safe in pregnancy (e.g., folic acid). 2. Category B: Animal studies show no harm; no well-controlled human studies (e.g., acetaminophen). 3. Category C: Animal studies show harm; use only if benefits outweigh risks (e.g., ciprofloxacin). 4. Category D: Evidence of risk to fetus; use in life-threatening situations (e.g., valproic acid). 5. Category X: Contraindicated in pregnancy (e.g., isotretinoin). Differences Among Pharmaceutics, Pharmacokinetics, Pharmacotherapeutics, and Pharmacodynamics Pharmaceutics: Study of drug formulation (e.g., tablets, capsules, injections). Pharmacokinetics: Study of how the body absorbs, distributes, metabolizes, and excretes drugs. Pharmacotherapeutics: Use of drugs to prevent, treat, or manage disease. Pharmacodynamics: Study of how drugs affect the body (e.g., mechanisms of action). Factors Influencing Medication Action Age: Infants and older adults metabolize drugs differently. Weight: Dosage often depends on body weight. Genetics: Genetic variations affect metabolism (e.g., enzyme deficiencies). Gender: Hormonal differences influence drug response. Health Status: Liver/kidney disease impacts metabolism and excretion. Route of Administration: IV drugs act faster than oral drugs. Types of Drug Reactions Side Effects: Predictable, mild, and often manageable effects (e.g., nausea). Adverse Effects: Harmful, unintended reactions (e.g., hepatotoxicity). Allergic Reactions: Immune responses (e.g., rash, anaphylaxis). Idiosyncratic Reactions: Unusual, unexpected reactions specific to an individual.  Toxic Effects: Harm due to drug overdose or accumulation. Medication Interactions and Incompatibility Medication Interactions: o Additive Effect: Two drugs with similar actions increase effect (e.g., opioids and sedatives). o Synergistic Effect: Two drugs enhance each other’s effects (e.g., antibiotics). o Antagonistic Effect: One drug reduces the effect of another. Incompatibility: Physical or chemical reactions occur when drugs are mixed, altering efficacy or safety (e.g., precipitate formation in IV solutions). Use of Herbal Therapy and Nutritional Supplements Herbal Therapy: Used for conditions like anxiety, inflammation, or immune support (e.g., chamomile, turmeric). Nutritional Supplements: Provide essential nutrients (e.g., vitamin D, omega-3 fatty acids). Nursing Considerations: o Evaluate for interactions with prescription drugs. o Educate patients about unregulated nature and potential risks. Nurse’s Role in Providing Culturally Safe Care in Medication Management Respect cultural beliefs and preferences regarding medications. Be aware of cultural influences on perceptions of illness and treatment. Educate in a way that aligns with the patient’s language, values, and health literacy. Assess for traditional or alternative medication use (e.g., herbal remedies). Impact of Age-Related Physiological Changes on Pharmacokinetics 1. Absorption: Reduced gastric acid and slowed gastric motility may delay drug absorption. 2. Distribution: Decreased body water and increased fat alter drug distribution. 3. Metabolism: Liver function declines with age, reducing metabolism of certain drugs. 4. Excretion: Reduced renal function leads to slower drug clearance and increased drug accumulation. Nursing Responsibilities Related to Cannabis for Medical Purposes Assessment: Determine patient eligibility and symptoms being treated with cannabis.  Education: Provide guidance on safe use, including dosing and potential side effects. Monitoring: Observe for adverse effects like sedation or anxiety. Documentation: Record patient use of cannabis, including effects and adherence to medical guidelines. Legislation: Follow federal and provincial regulations for cannabis use and storage. Unit 2: Anti-Infective Medications Medication Classifications 1. Sulfonamides a. Mechanism of Action: Inhibit bacterial folic acid synthesis by competing with para-aminobenzoic acid (PABA), preventing bacterial replication. b. Indications: Urinary tract infections (UTIs), respiratory infections, and certain GI infections. c. Contraindications: Allergy to sulfonamides, severe renal or hepatic dysfunction, and pregnancy/lactation. d. Adverse Effects: Allergic reactions (rash, Stevens-Johnson Syndrome), photosensitivity, GI upset, crystalluria, and blood dyscrasias. e. Interactions: Potentiates the effects of warfarin, phenytoin, and sulfonylureas. f. Nursing Considerations: Ensure adequate hydration to prevent crystalluria. Monitor renal function and blood counts. g. Patient Teaching: Drink plenty of fluids. Avoid excessive sunlight exposure. Report signs of rash or unusual bleeding. 2. β-Lactams (Penicillins and Cephalosporins) a. Mechanism of Action: Inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to cell lysis. b. Indications: Penicillins: Streptococcal infections, syphilis, and skin infections. Cephalosporins: Respiratory, urinary, and skin infections, as well as meningitis. c. Contraindications: Allergy to penicillins or cephalosporins. Severe renal impairment (adjust dosing). d. Adverse Effects: Allergic reactions (anaphylaxis, rash), GI upset, superinfections (e.g., C. difficile). e. Interactions: Reduced efficacy of oral contraceptives. Increased risk of bleeding with anticoagulants. f. Nursing Considerations: Monitor for allergic reactions, particularly after the first dose. Obtain cultures before starting therapy. g. Patient Teaching: Complete the entire course of antibiotics. Take as directed, with or without food based on the specific drug. Notify healthcare provider of any rash or diarrhea. 3. Monobactams a. Mechanism of Action: Inhibit bacterial cell wall synthesis, similar to β-lactams, but are structurally different, reducing cross-allergenicity. b. Indications: Gram-negative bacterial infections, such as Pseudomonas aeruginosa. c. Contraindications: Allergy to aztreonam or other monobactams. d. Adverse Effects: GI upset, rash, elevated liver enzymes, and rarely superinfections. e. Interactions: May interact with aminoglycosides, increasing nephrotoxicity risk. f. Nursing Considerations: Monitor liver and kidney function. Use cautiously in renal impairment. g. Patient Teaching: Report any unusual side effects, including jaundice or severe diarrhea. Follow the prescribed dosing schedule. 4. Macrolides (Erythromycin) a. Mechanism of Action: Inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit, halting bacterial growth. b. Indications: Respiratory infections, skin infections, and certain STIs (e.g., chlamydia). c. Contraindications: Allergy to macrolides, severe hepatic impairment, and use with certain drugs that prolong QT intervals. d. Adverse Effects: GI upset, prolonged QT interval, hepatotoxicity, and ototoxicity. e. Interactions: Inhibits the metabolism of drugs like warfarin, statins, and theophylline. Avoid use with other QT-prolonging medications. f. Nursing Considerations: Monitor liver function and ECG. Administer with food to minimize GI upset if allowed. g. Patient Teaching: Avoid grapefruit juice, which can increase drug levels. Report palpitations or hearing changes. 5. Tetracyclines a. Mechanism of Action: Inhibit bacterial protein synthesis by binding to the 30S ribosomal subunit. b. Indications: Acne, Lyme disease, respiratory infections, and chlamydia. c. Contraindications: Pregnancy, children under 8 years old (staining of teeth), and severe liver/kidney disease. d. Adverse Effects: Photosensitivity, GI upset, esophageal irritation, and teeth discoloration. e. Interactions: Reduced absorption with dairy, antacids, or iron supplements. f. Nursing Considerations: Administer 1-2 hours before or after meals. Avoid giving with calcium-containing products. g. Patient Teaching: Avoid sunlight or use sunscreen. Do not take with milk or antacids. 6. Aminoglycosides a. Mechanism of Action: Inhibit bacterial protein synthesis by binding irreversibly to the 30S ribosomal subunit, leading to bacterial death. b. Indications: Severe gram-negative bacterial infections. c. Contraindications: Allergy to aminoglycosides, renal impairment, and myasthenia gravis. d. Adverse Effects: Ototoxicity, nephrotoxicity, and neuromuscular blockade. e. Interactions: Increased nephrotoxicity with other nephrotoxic drugs (e.g., vancomycin, NSAIDs). f. Nursing Considerations: Monitor peak and trough levels to prevent toxicity. Assess hearing and renal function regularly. g. Patient Teaching: Report any hearing changes or difficulty urinating. Stay hydrated. 7. Quinolones a. Mechanism of Action: Inhibit bacterial DNA gyrase and topoisomerase IV, preventing DNA replication. b. Indications: UTIs, respiratory infections, and skin infections. c. Contraindications: Allergy to quinolones, pregnancy, and children (risk of tendon damage). d. Adverse Effects:  Tendonitis/tendon rupture, GI upset, photosensitivity, and QT prolongation. e. Interactions: Avoid antacids, dairy, and iron supplements. Increased effects of warfarin. f. Nursing Considerations: Administer 2 hours before/after antacids or dairy. Monitor for signs of tendon pain/swelling. g. Patient Teaching: Avoid strenuous physical activity. Use sunscreen and avoid direct sunlight. 8. Herbals: Cranberry and Goldenseal Cranberry Mechanism of Action: Prevents bacteria from adhering to the bladder wall. Indications: UTI prevention. Contraindications: Allergy to cranberries or high oxalate intake (kidney stones). Adverse Effects: GI upset and kidney stones with excessive use. Interactions: May potentiate warfarin. Goldenseal Mechanism of Action: Contains berberine, which may have antimicrobial properties. Indications: Used for infections and digestive issues. Contraindications: Pregnancy, breastfeeding, and certain cardiac conditions. Adverse Effects: GI upset and bradycardia. Interactions: Inhibits CYP450 enzymes, affecting drug metabolism. General Principles of Antibiotic Therapy 1. Obtain cultures before initiating antibiotics. 2. Use narrow-spectrum antibiotics when possible. 3. Monitor for adverse effects and superinfections. 4. Ensure the full course is completed. 5. Educate on the importance of adherence to therapy. Nursing Process for Administering Antibiotics 1. Assessment: o Assess allergies, renal and hepatic function, and infection symptoms. 2. Diagnosis: o Risk for infection, impaired renal function, or non-adherence to therapy. 3. Planning: o Plan dosing schedules and monitor therapeutic response. 4. Implementation: o Administer as prescribed, ensuring correct route and timing. 5. Evaluation: o Reassess infection symptoms, adverse effects, and patient understanding. Unit 3: Pain Management Medication Classifications: 1. Opioids (Agonists, Antagonists) a. Mechanism of Action: Agonists: Bind to opioid receptors (mu, kappa, delta) in the central nervous system (CNS) to block pain signals and produce analgesia. Antagonists: Compete with agonists for binding to opioid receptors, reversing or blocking the effects of opioids (e.g., Naloxone). b. Indications: Agonists: Moderate to severe pain, post-operative pain, chronic pain, and palliative care. Antagonists: Opioid overdose, respiratory depression reversal. c. Contraindications: Respiratory depression, severe asthma, or COPD. Caution in head injury, liver/kidney disease, and pregnancy. d. Adverse Effects: Sedation, respiratory depression, constipation, nausea, vomiting, dizziness, dependence, and withdrawal symptoms. e. Interactions: CNS depressants (e.g., alcohol, benzodiazepines). Monoamine oxidase inhibitors (MAOIs). Other opioids increase sedation and respiratory depression risk. f. Nursing Considerations: Monitor respiratory rate, sedation levels, and oxygen saturation. Use the lowest effective dose. Assess pain and response to medication regularly. g. Patient Teaching: Avoid alcohol and other CNS depressants. Do not operate heavy machinery while on opioids. Importance of adhering to prescribed doses to avoid overdose or dependence. 2. Non-Opioids a. Mechanism of Action: Reduce pain and fever by inhibiting prostaglandin synthesis (e.g., acetaminophen). b. Indications: Mild to moderate pain, fever. c. Contraindications: Liver dysfunction/disease (e.g., for acetaminophen). Hypersensitivity to the medication. d. Adverse Effects: Liver damage (with overdose or prolonged use). Rare skin reactions (e.g., Stevens-Johnson syndrome). e. Interactions: Alcohol increases the risk of liver damage. Warfarin increases bleeding risk when taken with acetaminophen. f. Nursing Considerations: Monitor liver function tests (LFTs) if used long-term. Watch for signs of overdose, such as nausea and confusion. g. Patient Teaching: Do not exceed the recommended daily dose (e.g., 4g/day for acetaminophen). Avoid alcohol. 3. Non-Steroidal Anti-Inflammatories (NSAIDs) a. Mechanism of Action: Inhibit cyclooxygenase (COX) enzymes (COX-1, COX-2), reducing prostaglandins to decrease inflammation, pain, and fever. b. Indications: Inflammation, mild to moderate pain, fever, arthritis, menstrual pain. c. Contraindications: Peptic ulcers, GI bleeding, renal dysfunction, and hypersensitivity to NSAIDs. Avoid in late pregnancy (risk of premature closure of the ductus arteriosus). d. Adverse Effects: GI upset, ulcers, bleeding, kidney dysfunction, cardiovascular events (e.g., myocardial infarction, stroke). e. Interactions: Increased bleeding risk with anticoagulants and antiplatelet drugs. Reduced efficacy of antihypertensives. f. Nursing Considerations: Administer with food to reduce GI upset. Monitor for signs of GI bleeding (e.g., black stools). g. Patient Teaching: Avoid taking NSAIDs on an empty stomach. Report any unusual bleeding or bruising. 4. Herbals (Willow Bark and Passionflower) Willow Bark a. Mechanism of Action: Contains salicin, metabolized to salicylic acid, which has anti-inflammatory and analgesic effects similar to aspirin. b. Indications:  Pain, fever, inflammation. c. Contraindications: Allergy to aspirin, bleeding disorders, and use in children (risk of Reye’s syndrome). d. Adverse Effects: GI upset, bleeding, allergic reactions. e. Interactions: Anticoagulants and NSAIDs increase bleeding risk. f. Nursing Considerations: Monitor for signs of bleeding and allergy. g. Patient Teaching: Avoid use with other anticoagulants. Inform healthcare providers about herbal use. Passionflower a. Mechanism of Action: Thought to enhance GABA activity, leading to sedative and anxiolytic effects. b. Indications: Anxiety, insomnia. c. Contraindications: Pregnancy, lactation, and use with sedatives. d. Adverse Effects: Drowsiness, dizziness, GI upset. e. Interactions: Enhanced sedative effects when combined with CNS depressants. f. Nursing Considerations: Monitor for excessive sedation. g. Patient Teaching: Avoid driving or operating machinery if drowsy. Nursing Process for Administering Medications 1. Assessment: o Assess pain, vital signs, allergies, and contraindications before administering. 2. Diagnosis: o Identify potential problems (e.g., risk of overdose, GI bleeding, or sedation). 3. Planning: o Plan appropriate timing and dosing for medication administration. 4. Implementation: o Administer the medication safely, ensuring proper dose and route. 5. Evaluation: o Reassess pain relief, adverse effects, and patient understanding of instructions. Impact of Opioids and NSAIDs on Older Populations Opioids: o Increased sensitivity to opioids; higher risk of respiratory depression, falls, and constipation. o Risk of polypharmacy interactions. NSAIDs: o Increased risk of GI bleeding, renal dysfunction, and cardiovascular events. o Should be used cautiously and with gastroprotective agents when necessary. Role of the LPN Regarding Naloxone Recognize signs of opioid overdose (e.g., respiratory depression, unresponsiveness). Administer Naloxone per protocol. Monitor patient post-administration for return of overdose symptoms (Naloxone has a short half- life). Provide education to the patient and family about overdose prevention and the use of Naloxone kits. Unit 4: Anesthesia and Psychotherapeutics 1. General Anaesthetics a. Mechanism of Action:  Depress the central nervous system (CNS) by enhancing inhibitory neurotransmitter activity (e.g., GABA) or reducing excitatory activity, resulting in loss of sensation and consciousness. b. Indications: Induction and maintenance of anesthesia for surgical procedures. c. Contraindications: Hypersensitivity, severe cardiovascular or respiratory disease, and susceptibility to malignant hyperthermia (for volatile anesthetics). d. Adverse Effects: Hypotension, respiratory depression, nausea/vomiting, post-operative confusion, and rarely malignant hyperthermia. e. Interactions: Potentiated by CNS depressants (e.g., benzodiazepines, opioids). Some agents may interact with muscle relaxants, increasing the risk of apnea. f. Nursing Considerations: Monitor vital signs closely during and after administration. Assess for history of malignant hyperthermia. Ensure emergency equipment is readily available. g. Patient Teaching: Explain the purpose and effects of general anesthesia. Warn about potential side effects like grogginess or nausea post-procedure. 2. Drugs for Procedural Sedation a. Mechanism of Action: Depress the CNS to a lesser extent than general anesthesia, providing sedation, analgesia, and anxiolysis without complete loss of consciousness. b. Indications: Minor surgical or diagnostic procedures (e.g., endoscopy, dental procedures). c. Contraindications: Severe respiratory or cardiovascular compromise.  Hypersensitivity to the sedative agent. d. Adverse Effects: Hypotension, bradycardia, respiratory depression, and paradoxical agitation in some cases. e. Interactions: Enhanced effects with CNS depressants (e.g., alcohol, opioids). f. Nursing Considerations: Monitor respiratory and cardiovascular status closely. Ensure resuscitative equipment is available. Titrate dose carefully to achieve desired sedation level. g. Patient Teaching: Inform patients they may feel drowsy or groggy after the procedure. Advise against driving or operating machinery for 24 hours. 3. Local Anaesthetics a. Mechanism of Action: Block sodium channels in nerve cells, preventing nerve signal transmission and causing localized numbness. b. Indications: Minor surgical or dental procedures, regional anesthesia, and pain management (e.g., epidural). c. Contraindications: Hypersensitivity to local anesthetics (amide or ester class). Infection or inflammation at the injection site. d. Adverse Effects: Rare systemic toxicity, including CNS excitation (tremors, seizures) and cardiovascular effects (arrhythmias, hypotension). Allergic reactions. e. Interactions: Potentiated by epinephrine, which prolongs duration by reducing blood flow. Risk of toxicity with other CNS depressants. f. Nursing Considerations: Monitor for signs of local anesthetic toxicity (e.g., metallic taste, CNS symptoms). Use smallest effective dose. g. Patient Teaching: Explain that numbness is temporary. Advise against eating or chewing until sensation returns to avoid injury. 4. Neuromuscular Blocking Drugs a. Mechanism of Action: Block acetylcholine at neuromuscular junctions, causing skeletal muscle paralysis. Classified as depolarizing (e.g., succinylcholine) or non-depolarizing (e.g., rocuronium). b. Indications: Facilitation of intubation, muscle relaxation during surgery, and mechanical ventilation. c. Contraindications: Hypersensitivity, history of malignant hyperthermia, electrolyte imbalances, or myasthenia gravis (for non-depolarizing agents). d. Adverse Effects: Respiratory paralysis, malignant hyperthermia, hyperkalemia (with succinylcholine), and prolonged paralysis. e. Interactions: Enhanced effect with aminoglycosides and other muscle relaxants. Reduced effect with some cholinesterase inhibitors. f. Nursing Considerations: Ensure mechanical ventilation is available. Monitor neuromuscular function and signs of recovery. Have reversal agents (e.g., neostigmine) on hand if appropriate. g. Patient Teaching: Explain the need for muscle paralysis and that effects will wear off after the procedure. Nursing Process for Administering Medications 1. Assessment: o Review patient history, including allergies, current medications, and medical conditions. o Assess baseline vitals, respiratory function, and level of consciousness. 2. Diagnosis: o Identify potential risks (e.g., ineffective airway clearance, anxiety related to anesthesia). 3. Planning: o Prepare medications and ensure emergency equipment is available. o Establish monitoring protocols. 4. Implementation: o Administer medications as prescribed, titrating doses as necessary. o Continuously monitor the patient’s status. 5. Evaluation: o Assess for intended effects (e.g., sedation, pain relief) and adverse effects. o Document observations and patient responses. Risks of Administering Nitrous Oxide Analgesia: Prolonged use may cause vitamin B12 deficiency and neurologic toxicity. Anesthesia: Risk of hypoxia (diffusion hypoxia if oxygen isn’t supplemented after discontinuation). Sedation: May cause nausea, vomiting, or excessive sedation in sensitive patients. Required Assessments for Nitrous Oxide Administration 1. Pre-Administration: o Assess baseline vitals and oxygen saturation. o Evaluate respiratory and cardiovascular status. o Screen for contraindications (e.g., pneumothorax, bowel obstruction, B12 deficiency). 2. During Administration: o Continuously monitor oxygen saturation, respiratory rate, and level of sedation. o Watch for signs of hypoxia or over-sedation. 3. Post-Administration: o Monitor recovery, ensuring oxygen saturation returns to baseline. o Observe for nausea, dizziness, or headache. Procedure: Administer via a calibrated delivery system with 100% oxygen supplementation before and after nitrous oxide use to prevent diffusion hypoxia. Impact of Anaesthesia in the Older Population Pharmacokinetics: o Reduced metabolism and clearance prolong drug effects.  o Increased sensitivity to anesthetic agents due to reduced CNS reserve. Risks: o Higher risk of hypotension, hypothermia, post-operative confusion, and delirium. Nursing Considerations: o Use the lowest effective doses. o Monitor for prolonged recovery and post-operative cognitive dysfunction (POCD). Unit 5: Respiratory Medications 1. Antihistamines (Non-Sedating vs. Traditional) a. Mechanism of Action: Non-Sedating: Block H1 histamine receptors, reducing allergic responses without crossing the blood-brain barrier, minimizing sedation (e.g., loratadine, cetirizine). Traditional (Sedating): Block H1 histamine receptors and cross the blood-brain barrier, leading to sedative effects (e.g., diphenhydramine, chlorpheniramine). b. Indications: Allergic rhinitis, hay fever, urticaria, anaphylaxis, and motion sickness (traditional). c. Contraindications: Allergy to antihistamines, severe liver impairment (non-sedating), or glaucoma, asthma, and COPD (traditional, due to thickened secretions). d. Adverse Effects: Non-Sedating: Headache, dry mouth, and fatigue (rare). Traditional: Drowsiness, dizziness, dry mouth, blurred vision, and urinary retention. e. Interactions: Non-sedating: Minimal drug interactions. Traditional: Enhanced CNS depression with alcohol, benzodiazepines, or opioids. f. Nursing Considerations: Assess allergy symptoms and evaluate for contraindications like glaucoma. Monitor for excessive sedation with traditional antihistamines. g. Patient Teaching: Non-Sedating: Safe for daytime use; avoid taking more than prescribed. Traditional: Avoid driving, alcohol, or CNS depressants. Stay hydrated to minimize dry mouth. 2. Decongestants a. Mechanism of Action: Stimulate alpha-adrenergic receptors to constrict nasal blood vessels, reducing nasal swelling and congestion (e.g., pseudoephedrine, oxymetazoline). b. Indications: Nasal congestion associated with colds, allergies, or sinusitis. c. Contraindications: Uncontrolled hypertension, severe coronary artery disease, hyperthyroidism, and glaucoma. d. Adverse Effects: Nervousness, insomnia, palpitations, rebound congestion (with prolonged topical use), and elevated blood pressure. e. Interactions: Hypertension risk with MAOIs. Additive stimulant effects with caffeine or other sympathomimetics. f. Nursing Considerations: Monitor blood pressure, especially in patients with cardiovascular disease. Limit topical decongestant use to 3-5 days to avoid rebound congestion. g. Patient Teaching: Use topical decongestants sparingly to avoid rebound congestion. Take oral decongestants in the morning to prevent insomnia. 3. Antitussives a. Mechanism of Action: Opioid Antitussives: Suppress the cough reflex by acting on the cough center in the medulla (e.g., codeine). Non-Opioid Antitussives: Act peripherally or centrally to reduce cough sensitivity (e.g., dextromethorphan). b. Indications: Dry, non-productive cough. c. Contraindications: Productive cough requiring expectoration (to avoid mucus retention). Hypersensitivity to opioids (for opioid antitussives). d. Adverse Effects: Opioids: Sedation, constipation, respiratory depression (at high doses). Non-Opioids: Dizziness, nausea, mild drowsiness. e. Interactions: Enhanced CNS depression with alcohol or sedatives. Risk of serotonin syndrome with MAOIs or SSRIs (for dextromethorphan). f. Nursing Considerations: Assess for underlying causes of the cough. Monitor for sedation and respiratory depression, especially with opioids. g. Patient Teaching: Avoid driving or operating machinery if drowsy. Use only as directed and avoid alcohol or other CNS depressants. 4. Expectorants a. Mechanism of Action: Increase respiratory tract fluid secretion, thinning mucus to make it easier to expectorate (e.g., guaifenesin). b. Indications: Productive cough associated with colds, bronchitis, or respiratory infections. c. Contraindications: Hypersensitivity to the drug. Caution in chronic respiratory conditions like asthma or COPD. d. Adverse Effects: Nausea, vomiting, dizziness, and mild GI upset. e. Interactions:  Few significant interactions. f. Nursing Considerations: Ensure the patient stays hydrated to aid mucus thinning. Assess effectiveness of the medication in improving cough productivity. g. Patient Teaching: Drink plenty of fluids to enhance the effect. Report persistent cough or signs of infection (e.g., fever, purulent sputum). Nursing Process for Administering These Medications 1. Assessment: o Assess symptoms (e.g., type of cough, nasal congestion, allergy signs). o Review medical history for contraindications (e.g., glaucoma, hypertension). o Check for interactions with current medications. 2. Diagnosis: o Example: Ineffective airway clearance related to excessive mucus production or congestion. 3. Planning: o Select appropriate medication based on patient symptoms. o Plan for monitoring response to therapy. 4. Implementation: o Administer medications as prescribed, ensuring proper route and timing. o Monitor for side effects like sedation, hypertension, or rebound congestion. 5. Evaluation: o Assess symptom improvement (e.g., reduced congestion, decreased cough). o Monitor for adverse effects and patient adherence to therapy.