Cholinergic Drugs: Uses, Side Effects & Examples

Cholinergic Drugs

• Examples: Donepezil, Pilocarpine, Rivastigmine, Memantine
• Indications: Alzheimer's disease (Donepezil), glaucoma, intraocular surgery (Pilocarpine), dry mouth (e.g., surgeon's syndrome). Bethanechol increases bladder tone/motility, cevimeline treats excessive dry mouth.
• Mechanism of Action: Enhance acetylcholine effects (inhibit breakdown or mimic action)
• Patient Education (Alzheimer's): Effects may take up to 6 weeks. Urinary retention patients: urination should occur within 60 minutes of bethanechol.
• Symptoms: Increased secretions, bradycardia, bronchoconstriction, diarrhea.
• Contraindications: Bradycardia, epilepsy, hypotension, COPD, peptic ulcers.
• Adverse Effects: Decreased heart rate, hypotension, respiratory distress, excessive salivation/sweating, bronchial constriction.
• Antidote: Pyridostigmine (reverses anticholinergic poisoning)
• Early Overdose Signs: Abdominal cramps, salivation, skin flushing, nausea, vomiting, transient syncope, transient heart block, dyspnea, orthostatic hypotension.

Anticholinergics

• Examples: Scopolamine, Glycopyrrolate (Robinul)
• Mechanism of Action: Block acetylcholine to reduce secretions and smooth muscle contractions.
• Atropine: Use in bradycardia, ventricular asystole; antidote for anticholinesterase inhibitor toxicity/poisoning; pre-operatively to reduce salivation and GI secretions.
• Scopolamine: Motion sickness prevention, postoperative/post-anesthesia nausea/vomiting prevention.
• Tolterodine: Urinary frequency, urgency, urge incontinence due to bladder overactivity.
• Uses: Motion sickness (Scopolamine), preoperative drying of secretions (Glycopyrrolate), muscle rigidity and tremor reduction (Parkinson's).
• Contraindications: Angle-closure glaucoma.
• Symptoms: Dry mouth, blurred vision, urinary retention, decreased bronchial secretions.
• Side Effects: Constipation, tachycardia, confusion.
• Patient Education: Increased fluid intake, report urinary retention/hesitancy, constipation.
• Antidote: Physostigmine.

Anti-Hypertension, Anti-Angina, HF, Anti-Dysrhythmic, Diuretics

• ACE Inhibitors (e.g., Lisinopril, Enalapril, Captopril): First-line for heart failure and hypertension; often combined with thiazide diuretics or CCBs; reduce heart workload, glomerular filtration pressure; prevent diabetic nephropathy.
• ARBs (e.g., Losartan): Primarily affect vascular smooth muscle and adrenal gland.
• CCBs (e.g., Diltiazem): Primarily for hypertension and angina.
• BBs (e.g., Metoprolol, Carvedilol, Atenolol): Slow heart rate, reduce cardiac workload.
• Vasodilators (e.g., Nitroglycerin, Isosorbide, Minoxidil): Relax blood vessels (Minoxidil for hair regrowth).
• Diuretics (e.g., Hydrochlorothiazide, Spironolactone, Mannitol, Diamox): Increase urine output; thiazides common for hypertension.
• Anti-Dysrhythmics (e.g., Amiodarone, Adenosine, Digoxin, Atropine): Manage abnormal heart rhythms.
• Inotropes (e.g., Dobutamine): Increase heart contractility.
• Antiplatelets (e.g., Plavix, Aspirin, Pradaza, Brilinta): Prevent platelet aggregation.
• Statins (e.g., Rosuvastatin, Atorvastatin): Lower cholesterol and triglycerides.
• Misc Antihypertensive (e.g., Eplerenone): Contraindicated with serum potassium above 5.6 mEq/L.
• Sildenafil/Tadalafil: Erectile dysfunction, pulmonary hypertension (different trade names).
• Indications: Hypertension, angina, heart failure, dysrhythmias. Hypertensive emergencies managed with sodium nitroprusside and IV diazoxide.
• Symptoms: Hypotension, bradycardia, electrolyte imbalances.
• Patient Teaching: Rise slowly, monitor BP regularly, avoid sudden discontinuation (taper over 1-2 weeks).
• Complications: Organ damage (kidneys, heart), electrolyte imbalances, arrhythmias.
• Mechanism of Action: ACE/ARB: Inhibit RAAS; CCB: Reduce calcium entry; BB: Slow HR; Vasodilators: Relax vessels; Diuretics: Increase urine output.
• Drug Interactions: NSAIDs, potassium supplements (ACE/ARB). Avoid combining with other BP-lowering meds.
• Contraindications: Pregnancy (ACE/ARB), severe bradycardia (BBs).

Thiazide Diuretics (e.g. Hydrochlorothiazide (HCTZ))

• Mechanism: Inhibits sodium/chloride reabsorption in the distal tubule.
• Indications: Hypertension, edema, heart failure, hepatic cirrhosis.
• Complications: Dehydration, electrolyte imbalances, hypotension.
• Side Effects: Hypokalemia, hyperglycemia, jaundice, leukopenia.
• Nursing Action: Avoid if CrCl < 30-50 mL/min, take in the morning, avoid excessive licorice intake.

Loop Diuretics (e.g. Furosemide (Lasix))

• Mechanism: Inhibits sodium/chloride reabsorption in the loop of Henle.
• Indications: Heart failure, renal failure, edema, hypertension.
• Complications: Electrolyte imbalances, dehydration, ototoxicity.
• Drug Interactions: Increases digoxin toxicity; nephrotoxicity with antibiotics, lithium.
• Contraindications: Sulfonamide allergy.
• Side Effects: Hypokalemia, hypocalcemia, hypotension.

Potassium-Sparing Diuretics (e.g. Spironolactone (Aldactone))

• Mechanism: Blocks aldosterone in the distal tubule; prevents sodium reabsorption, and potassium excretion.
• Indications: Hyperaldosteronism, hypertension, reversing potassium loss from potassium-losing drugs.
• Drug Interactions: Lithium.

Osmotic Diuretics (e.g. Mannitol)

• Mechanism: Increases osmolarity, drawing water into the kidneys and promoting diuresis.
• Indications: Decreasing intracranial pressure, early acute renal failure, cerebral edema.
• Drug Interactions: Potentiates other diuretics.
• Contraindications: Severe renal disease, dehydration, intracranial bleeding.
• Side Effects: Convulsions
• Nursing Actions: Watch for crystallization if stored at low temperatures, use filters.

Carbonic Anhydrase Inhibitors (e.g. Acetazolamide)

• Mechanism: Inhibits carbonic anhydrase, reducing bicarbonate reabsorption.
• Indications: Glaucoma, altitude sickness, metabolic alkalosis.
• Drug Interactions: Because CAIs can cause hypokalemia, digoxin toxicity may occur.
• Contraindications: Hyponatremia, hypokalemia, cirrhosis

Coagulation Modifiers

Anticoagulants

• Examples: Warfarin (Coumadin), Heparin, Enoxaparin (Lovenox), Apixaban (Eliquis), Dabigatran (Pradaxa)
• Indications: DVT, PE, AFib, stroke prevention, mechanical heart valves.
• Lab Monitoring: Warfarin: PT/INR; Heparin: aPTT; DOACs: No routine labs.
• Nursing Actions: Monitor for bleeding, check INR/aPTT, avoid IM injections.
• Patient Teaching: Report bleeding, avoid NSAIDs, maintain consistent vitamin K intake (Warfarin).
• Dosing: Warfarin: 2-10 mg/day; Heparin: IV infusion; Enoxaparin: 1 mg/kg SC q12h; Eliquis: 5 mg BID.
• Onset: Warfarin: 27-72 hours; Heparin: 20-30 minutes; Enoxaparin: 3-5 hours.
• Adverse Reactions: Bleeding, heparin-induced thrombocytopenia (HIT)
• Antidotes: Warfarin (Vitamin K); Heparin (Protamine sulfate); Apixaban (Andexanet alfa).

Antiplatelets

• Examples: Aspirin, Clopidogrel (Plavix)
• Indications: Stroke, MI prevention, PAD.
• Lab Monitoring: No routine labs.
• Nursing Actions: Monitor for GI bleeding, check platelets.
• Patient Teaching: Avoid NSAIDs, report unusual bleeding.
• Dosing: Aspirin 81-325 mg daily, Clopidogrel 75 mg daily.
• Onset: Aspirin: 60 min, Clopidogrel: 2 hrs.
• Adverse Reactions: Bleeding, GI ulcers.
• Antidote: Platelet transfusion (severe bleeding).

Thrombolytics

• Examples: Alteplase (tPA)
• Indications: Ischemic stroke, massive PE, acute MI.
• Lab Monitoring: PT, aPTT, INR, fibrinogen.
• Nursing Actions: Strict bleeding precautions, frequent neuro checks.
• Patient Teaching: Report severe headaches.
• Dosing: 0.9 mg/kg IV (max 90 mg stroke).
• Onset: 30-60 min.
• Adverse Reactions: Hemorrhage, stroke, hypotension.
• Antidote: Aminocaproic acid (Amicar).

Antifibrinolytics

• Examples: Desmopressin (DDAVP)
• Indications: Bleeding prevention/treatment (hemophilia, von Willebrand disease).
• Lab Monitoring: PT, aPTT, bleeding time.
• Nursing Actions: Monitor for thrombotic complications.
• Patient Teaching: Report clot formation (leg pain, shortness of breath).
• Dosing: 0.3 mcg/kg IV over 15-30 min.
• Onset: 30-60 min.
• Adverse Reactions: Hyponatremia, thrombotic events.
• Antidote: Supportive care, fluid restriction (hyponatremia).

Antilipemic Drugs (e.g., Rosuvastatin, Atorvastatin)

• Indications: Lower cholesterol and triglycerides.
• Patient Teaching: Take in the evening, report muscle pain.
• Triglycerides & Cholesterol: HDL (good), LDL (bad), total cholesterol monitoring.
• Contraindications: Liver disease, pregnancy.
• Labs to Monitor: Liver enzymes (ALT, AST), lipid panel.
• Nutrition/Diet: Low-fat diet, increase fiber intake.
• Drug/Food Interaction: Avoid grapefruit juice.

Overview of cholinergic drugs, including examples like Donepezil and Pilocarpine, their mechanisms of action, indications such as Alzheimer's and glaucoma, and potential side effects. Also covers contraindications, overdose signs and patient education.