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Pharmacology

Drug classes, mechanisms, side effects, and nursing considerations

Drug Classifications

Expand each card to review mechanism of action, side effects, and key nursing considerations.

Mechanism of Action: Blocks beta-1 receptors, decreasing heart rate, blood pressure, and myocardial oxygen demand.
Key Side Effects: Bradycardia, hypotension, fatigue, bronchospasm
Nursing Considerations: Check apical pulse before administration; hold if <60 BPM. Monitor BP. Do not stop abruptly — taper to avoid rebound tachycardia.
Mechanism of Action: Blocks angiotensin-converting enzyme (ACE), decreasing angiotensin II production → vasodilation and reduced aldosterone secretion.
Key Side Effects: Dry cough, hyperkalemia, angioedema
Nursing Considerations: Monitor BP and serum K⁺ levels. Watch for signs of angioedema (facial swelling, difficulty breathing) — discontinue immediately if suspected.
Mechanism of Action: Blocks calcium influx in vascular smooth muscle and myocardium, causing vasodilation and reduced cardiac contractility.
Key Side Effects: Peripheral edema, bradycardia, constipation
Nursing Considerations: Monitor BP and HR. Assess for peripheral edema. Educate patient on dietary fiber/fluids to manage constipation.
Mechanism of Action: Inhibits Na⁺/K⁺/2Cl⁻ cotransporter in the thick ascending limb of the loop of Henle, producing rapid diuresis.
Key Side Effects: Hypokalemia, dehydration, ototoxicity
Nursing Considerations: Monitor strict I&O and daily weights. Check serum K⁺ levels. Administer in the morning to prevent nocturia. Monitor for hearing changes with high doses.
Mechanism of Action: Binds mu opioid receptors in the CNS, altering pain perception and emotional response to pain.
Key Side Effects: Respiratory depression, constipation, sedation, nausea/vomiting
Nursing Considerations: Assess respiratory rate before administration — hold if RR <12/min. Monitor sedation level. Have naloxone available. Implement bowel regimen proactively.
Mechanism of Action: Enhances GABA effects on the CNS by binding to GABA-A receptors, producing anxiolytic, sedative, and anticonvulsant effects.
Key Side Effects: Sedation, dependence, respiratory depression (with opioids)
Nursing Considerations: Assess sedation level using a validated scale. Implement fall precautions. Avoid alcohol. Taper dose gradually to discontinue — do not stop abruptly.
Mechanism of Action: Promotes glucose uptake into cells, inhibits hepatic glucose production, and stimulates glycogen and lipid synthesis.
Key Side Effects: Hypoglycemia, hypokalemia, lipodystrophy
Nursing Considerations: Rotate injection sites to prevent lipodystrophy. Verify dose with a second nurse. Know onset/peak/duration for each insulin type. Monitor blood glucose and K⁺.
Mechanism of Action: Inhibits vitamin K-dependent clotting factors (II, VII, IX, X) and anticoagulant proteins C and S.
Key Side Effects: Bleeding, easy bruising
Nursing Considerations: Monitor PT/INR regularly — therapeutic range is typically 2–3. Teach patient to maintain consistent vitamin K intake (green leafy vegetables). Assess for signs of bleeding: bruising, petechiae, hematuria, melena.
Mechanism of Action: Beta-lactam antibiotics that bind to penicillin-binding proteins (PBPs), inhibiting bacterial cell wall synthesis and causing cell lysis. Bactericidal against actively dividing gram-positive and some gram-negative bacteria.
Key Side Effects: Rash, GI upset (nausea/diarrhea), superinfection (C. diff, yeast), anaphylaxis (rare)
Nursing Considerations: Always assess for penicillin allergy before administering — cross-sensitivity with cephalosporins possible. Monitor for signs of superinfection: oral thrush, vaginal yeast, C. diff diarrhea (watery, foul-smelling stools). Teach patient to take entire course even if feeling better. Administer on an empty stomach for best absorption.
Mechanism of Action: Beta-lactam antibiotics that disrupt bacterial cell wall synthesis, similar to penicillins. Grouped into generations (1st–5th) with expanding gram-negative coverage in higher generations.
Key Side Effects: GI upset, rash, superinfection, cross-sensitivity with penicillin (5–10%)
Nursing Considerations: Assess for penicillin allergy — cross-sensitivity risk ~5–10%. Avoid alcohol with cefotetan (disulfiram-like reaction). Monitor renal function (some require dose adjustment). Ceftriaxone is not compatible with calcium-containing IV solutions in neonates. Teach patient to report severe diarrhea immediately.
Mechanism of Action: Inhibit bacterial DNA gyrase and topoisomerase IV, blocking DNA replication. Broad-spectrum bactericidal activity against gram-negative and some gram-positive organisms.
Key Side Effects: Tendon rupture (Achilles), QT prolongation, photosensitivity, GI upset, CNS effects (dizziness, confusion)
Nursing Considerations: Black box warning: increased risk of tendonitis and tendon rupture, especially in patients >60, on corticosteroids, or with renal/heart/lung transplant. Avoid administration within 2 hours of antacids, calcium, iron, or zinc (chelation reduces absorption). Monitor for QT prolongation. Teach sun protection.
Mechanism of Action: Selectively inhibit serotonin reuptake in the CNS by blocking SERT transporters, increasing synaptic serotonin levels. Takes 4–6 weeks for full therapeutic effect.
Key Side Effects: Nausea, insomnia or sedation, sexual dysfunction, weight changes, serotonin syndrome (with MAOIs, St. John's Wort, other serotonergics)
Nursing Considerations: Onset of therapeutic effect is 4–6 weeks — patient education is critical for adherence. Taper gradually to discontinue (withdrawal syndrome: dizziness, flu-like symptoms, 'brain zaps'). Monitor for serotonin syndrome: hyperthermia, rigidity, myoclonus, confusion, autonomic instability. Contraindicated with MAOIs — 14-day washout required.
Mechanism of Action: Dopamine D₂ receptor antagonists. Atypicals (risperidone) also block serotonin 5-HT₂A receptors. Reduce positive symptoms (hallucinations, delusions) of schizophrenia.
Key Side Effects: EPS (dystonia, akathisia, parkinsonism, tardive dyskinesia), NMS, metabolic syndrome (atypicals: weight gain, hyperglycemia, dyslipidemia), sedation, orthostatic hypotension
Nursing Considerations: Monitor for EPS: assess with AIMS scale. NMS is a medical emergency — hyperthermia, lead-pipe rigidity, altered mental status, autonomic instability, elevated CK. Stop drug, cool patient, dantrolene/bromocriptine. Monitor weight, fasting glucose, and lipids every 3–6 months with atypicals. Educate that full effects may take several weeks.
Mechanism of Action: Albuterol: selective beta-2 adrenergic agonist → bronchodilation via smooth muscle relaxation. Ipratropium: muscarinic antagonist → blocks bronchoconstriction and reduces secretions. SABA = short-acting beta agonist (rescue); anticholinergic = maintenance.
Key Side Effects: Albuterol: tachycardia, tremors, nervousness, palpitations, hypokalemia. Ipratropium: dry mouth, throat irritation, blurred vision if contacts eyes.
Nursing Considerations: Albuterol is rescue — if using >2x/week, asthma not controlled (need controller therapy). Teach proper inhaler technique: shake, exhale fully, slow deep inhalation, hold breath 10 seconds. Wait 1 minute between puffs. Paradoxical bronchospasm possible — if wheezing worsens after dose, hold and notify provider. Rinse mouth after ipratropium to reduce dry mouth.
Mechanism of Action: Inhibits Na⁺/K⁺-ATPase pump → increased intracellular Na⁺ → increased Ca²⁺ via Na⁺/Ca²⁺ exchanger → positive inotropy (stronger contractions). Also enhances vagal tone → decreased AV conduction and slower ventricular rate in atrial fibrillation.
Key Side Effects: Bradycardia, blurred/yellow vision (xanthopsia), N/V, anorexia, fatigue, arrhythmias (PVCs, heart block)
Nursing Considerations: Check apical pulse for 1 full minute before administration — hold if <60 BPM (adults). Therapeutic range: 0.5–2 ng/mL. Hypokalemia dramatically increases toxicity risk — monitor K⁺ levels closely, especially with concurrent diuretics. Visual disturbances (halos, yellow-green tint) are classic toxicity signs. Elderly at higher risk due to decreased renal clearance.
Mechanism of Action: Metformin: decreases hepatic glucose production, increases peripheral insulin sensitivity. Sulfonylureas: stimulate pancreatic beta cells to secrete more insulin.
Key Side Effects: Metformin: GI upset (diarrhea, nausea, metallic taste), lactic acidosis (rare but fatal). Sulfonylureas: hypoglycemia, weight gain.
Nursing Considerations: Metformin: hold 24–48 hours before and after contrast dye procedures (increased lactic acidosis risk with renal impairment). Contraindicated if eGFR <30. Take with meals to reduce GI side effects. Sulfonylureas: major risk is hypoglycemia — teach s/s and treatment (15g fast-acting carbs). Avoid alcohol (disulfiram-like reaction with some sulfonylureas).
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High-Yield Drug Interactions

NCLEX frequently tests these interactions — know them cold.

Drug CombinationRisk
Warfarin + NSAIDsSevere bleeding risk — NSAIDs increase warfarin's anticoagulant effect and cause GI irritation.
ACE Inhibitors + K⁺-sparing diureticsHyperkalemia — both drug classes increase potassium levels.
MAOIs + tyramine-rich foodsHypertensive crisis — tyramine (aged cheese, cured meats, red wine) triggers massive norepinephrine release in the presence of MAOIs.
Metronidazole + alcoholDisulfiram-like reaction — severe nausea, vomiting, flushing, and headache within 15–30 minutes of alcohol consumption.
Theophylline + ciprofloxacinTheophylline toxicity — ciprofloxacin inhibits theophylline metabolism, leading to elevated serum levels, seizures, and arrhythmias.
Grapefruit juice + statinsIncreased statin levels → risk of rhabdomyolysis and hepatotoxicity. Grapefruit juice inhibits CYP3A4, the enzyme that metabolizes atorvastatin, simvastatin, and lovastatin. Avoid grapefruit products with these statins.
Lithium + NSAIDsLithium toxicity — NSAIDs (especially indomethacin) reduce renal clearance of lithium, causing elevated serum levels. Monitor lithium levels closely; may require dose reduction. Acetaminophen is a safer alternative for pain/fever.
Warfarin + antibioticsIncreased INR and bleeding risk — many antibiotics (especially fluoroquinolones, metronidazole, macrolides, sulfonamides) potentiate warfarin by killing vitamin K-producing gut flora and/or inhibiting warfarin metabolism. Monitor INR frequently during and after antibiotic course.

Key Mnemonics

Memory aids to help you recall critical nursing pharmacology concepts.

MONA — Acute MIMorphine, Oxygen, Nitroglycerin, Aspirin

Immediate interventions for suspected myocardial infarction. Morphine reduces pain and preload; O₂ for hypoxia; Nitro for vasodilation; Aspirin for antiplatelet effect.

SLUDGE — Cholinergic CrisisSalivation, Lacrimation, Urination, Defecation, GI distress, Emesis

Classic signs of excess acetylcholine (organophosphate poisoning, cholinergic drugs). Antidote: atropine and pralidoxime.

Always Check Pulse Before — Beta Blockers, Digoxin, Calcium Channel Blockers

These drugs can cause bradycardia. Check apical pulse for 1 full minute. Hold if below ordered parameters (commonly &lt;60 BPM).

Some Drugs Require Very Fine MonitoringSulfonylureas, Digoxin, Warfarin (Coumadin), Vancomycin

These drugs need careful lab monitoring due to narrow therapeutic windows or high-risk profiles: Sulfonylureas (blood glucose), Digoxin (serum levels, K⁺), Warfarin (PT/INR), Vancomycin (trough levels, renal function, ototoxicity). All four are high-alert medications — double-check dosing.