Enalapril

# Enalapril ## Overview - **Classification**: Angiotensin-Converting Enzyme (ACE) Inhibitor - **Mechanism**: Blocks conversion of Angiotensin I to Angiotensin II, leading to vasodilation, decreased aldosterone secretion, and reduced sympathetic activity. ## Primary Indications 1. **Hypertension** - Management of high blood pressure. 2. **Symptomatic Heart Failure** - Treatment to improve symptoms and reduce mortality. 3. **Asymptomatic Left Ventricular Dysfunction** - Prevention of symptomatic heart failure. ## Adult Dosing ### Standard Dosing **Hypertension** - **Dose**: Initial **2.5 mg** to **5 mg** - **Frequency**: Once daily - **Route**: Oral - **Maintenance**: **10 mg** to **40 mg** daily in 1-2 divided doses. **Symptomatic Heart Failure / Asymptomatic Left Ventricular Dysfunction** - **Dose**: Initial **2.5 mg** - **Frequency**: Once daily or twice daily - **Route**: Oral - **Titration**: Gradually increase to target **10 mg** to **20 mg** twice daily, as tolerated. ### Dose Adjustments - **Renal Impairment**: - CrCl 30-80 mL/min: Initial dose **2.5 mg** once daily. - CrCl <30 mL/min (including dialysis): Initial dose **2.5 mg** once daily. - Administer on dialysis days for dialysis patients. - **Hepatic Impairment**: No specific adjustments, use with caution. - **Elderly Patients**: Start with lower initial dose (**2.5 mg**), titrate slowly. Increased risk of adverse effects. ## Pediatric Dosing ### Neonates (0-28 days) - **Dose**: **0.08 mg/kg** - **Frequency**: Every 24 hours - **Maximum**: Not well-established due to high risk of adverse effects. - **Special Notes**: Use with extreme caution; consider alternative if possible. ### Infants (1-12 months) - **Dose**: **0.08 mg/kg** - **Frequency**: Once daily - **Maximum**: Initial max **5 mg** once daily. - **Titration**: May titrate up to **0.5 mg/kg/day** (max **40 mg/day**). ### Children (1-12 years) - **Dose**: **0.08 mg/kg** - **Frequency**: Once daily - **Maximum**: Initial max **5 mg** once daily. - **Titration**: May titrate up to **0.5 mg/kg/day** (max **40 mg/day**). ### Adolescents (13-18 years) - **Dose**: Use adult dosing guidelines. - **Maximum**: **40 mg** per day. - **Special Notes**: Monitor closely for initial hypotension. ## Safety Information ### Contraindications - **Absolute**: History of angioedema related to ACE inhibitor therapy. - **Absolute**: Hereditary or idiopathic angioedema. - **Absolute**: Concomitant use with aliskiren in patients with diabetes or renal impairment (CrCl <60 mL/min). - **Absolute**: Pregnancy (especially second and third trimesters). ### Common Adverse Effects - **Very Common (>10%)**: Dizziness, dry persistent **cough**, fatigue. - **Common (1-10%)**: Headache, nausea, diarrhea, hypotension, asthenia. - **Serious but Rare**: **Angioedema** (swelling of face, lips, tongue, larynx), hyperkalemia, acute renal failure, severe hypotension. ### Key Drug Interactions - **Potassium-sparing diuretics/Potassium supplements**: Increased risk of **hyperkalemia**. Monitor potassium levels closely. - **NSAIDs (e.g., ibuprofen, naproxen)**: May reduce hypotensive effect; increased risk of renal impairment. Monitor renal function. - **Lithium**: May increase lithium levels and toxicity. Monitor lithium levels. - **Aliskiren**: Contraindicated in diabetes/renal impairment; increased risk of renal failure, hyperkalemia, hypotension. ## Monitoring & Follow-up - **Before Treatment**: Baseline BP, renal function (SCr, BUN), electrolytes (K+). - **During Treatment**: - BP: Regularly, especially after initial dose or dose increase. - Renal Function (SCr, BUN): Periodically, particularly in first few weeks. - Electrolytes (K+): Periodically, especially with renal impairment or K+-sparing diuretics. - **Clinical Signs**: Monitor for angioedema (swelling of face, mouth), persistent dry cough, symptoms of hyperkalemia. ## Clinical Pearls - 💡 **Tip 1**: Administer first dose at bedtime to minimize initial "first-dose" hypotension. - 💡 **Tip 2**: Persistent dry cough is a common side effect; consider ARB if cough is bothersome. - 💡 **Tip 3**: Advise patients to avoid potassium supplements or salt substitutes unless directed by a prescriber. - 💡 **Tip 4**: Discontinue immediately and seek emergency care if **angioedema** occurs. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.