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Amlodipine

Amlodipine

Norvasc Istin Amvaz Katerzia

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Updated: December 06, 2025

Overview

Amlodipine is a long-acting dihydropyridine calcium channel blocker widely used in the management of hypertension and angina pectoris. It exerts its therapeutic effects by selectively inhibiting calcium ion influx across cell membranes in vascular smooth muscle and cardiac muscle, resulting in peripheral vasodilation and reduced myocardial oxygen demand. The drug is particularly valued for its favorable pharmacokinetic profile, including once-daily dosing and gradual onset of action, which minimizes reflex tachycardia. Amlodipine has demonstrated efficacy in various patient populations and is often used as first-line therapy for hypertension due to its generally well-tolerated side effect profile.

Drug Class

Dihydropyridine calcium channel blocker Antihypertensive agent Anti-anginal agent

Mechanism of Action

Amlodipine selectively inhibits transmembrane influx of calcium ions through L-type voltage-gated calcium channels in: • Vascular smooth muscle: Causes peripheral arterial vasodilation • Cardiac muscle: Reduces afterload and myocardial oxygen demand This results in: • Decreased peripheral vascular resistance • Reduced coronary vasospasm • Improved myocardial oxygen supply/demand ratio

Pharmacokinetics

Absorption: Well-absorbed orally with 60-65% bioavailability Distribution: Extensive tissue distribution with 95-98% plasma protein binding Metabolism: Hepatic via CYP3A4 to inactive metabolites Excretion: Primarily renal (60%) with 20-25% fecal excretion Half-life: 30-50 hours (permits once-daily dosing)

Pharmacodynamics

Primary effects: • Dose-dependent reduction in systemic vascular resistance • Increased coronary blood flow • Mild natriuretic effect Secondary effects: • Reflex sympathetic activation (minimal due to gradual onset) • Peripheral edema (dose-dependent) • Potential negative inotropy (minimal in therapeutic doses)

Indications

• Hypertension: Management of essential hypertension in adults and pediatric patients ≥6 years • Chronic stable angina: Symptomatic improvement and increased exercise tolerance • Vasospastic angina (Prinzmetal's angina): Prevention of coronary artery spasm

Contraindications

Absolute: • Hypersensitivity to amlodipine or other dihydropyridines • Severe hypotension (SBP <90 mmHg) Relative: • Aortic stenosis • Severe hepatic impairment • Heart failure with reduced ejection fraction

Dosage & Administration

Hypertension: • Adults: Initial 5 mg once daily, may increase to 10 mg after 7-14 days • Pediatrics (6-17 years): 2.5-5 mg once daily Chronic stable angina/Vasospastic angina: • Adults: Initial 5 mg once daily, may increase to 10 mg Maximum dose: 10 mg daily for all indications

Special Populations

Pediatric: Safety established ≥6 years; use smallest effective dose Geriatric: Start with lower initial dose (2.5 mg) Renal impairment: No dose adjustment required Hepatic impairment: Reduce initial dose to 2.5 mg; titrate carefully

Adverse Effects

Common (>10%): • Peripheral edema (dose-dependent) • Headache • Flushing • Palpitations Serious (<1%): • Severe hypotension • Acute liver injury • Angioedema • Myocardial infarction (rare)

Drug Interactions

• CYP3A4 inhibitors (ketoconazole, itraconazole): Increase amlodipine levels • Simvastatin: Limit to 20 mg daily with amlodipine • Other antihypertensives: Additive hypotensive effects • Cyclosporine: May increase cyclosporine levels

Warnings & Precautions

• Risk of worsening angina or acute MI after initiation • May cause symptomatic hypotension in volume-depleted patients • Peripheral edema may be dose-limiting • Use caution in patients with severe obstructive CAD • Monitor hepatic function in patients with liver disease

Pregnancy & Lactation

Pregnancy: FDA Category C • Safety not established; use only if benefit justifies risk • May cause maternal hypotension and reduced uteroplacental perfusion Lactation: Excreted in breast milk • Consider discontinuing nursing or medication • Monitor infant for potential effects

Monitoring Parameters

• Blood pressure (regular measurements) • Heart rate • Peripheral edema assessment • Liver function tests (periodic) • Angina symptoms and frequency • Body weight changes

Patient Counseling

• Take at same time daily, with or without food • Do not discontinue abruptly • Report swelling of feet/ankles or dizziness • Avoid grapefruit juice (may increase drug levels) • Rise slowly from sitting/lying position • Inform providers about all medications/supplements

Storage & Stability

• Store at 20-25°C (68-77°F) • Protect from light and moisture • Keep in original container • Stable for 6 weeks after removal from blister pack

Clinical Pearls

• Peripheral edema often improves with dose reduction • More effective for hypertension in African-American patients compared to other antihypertensives • Excellent choice for patients with asthma or diabetes • Minimal effect on lipid profile or glucose metabolism • Consider combination therapy for resistant hypertension

References

• Lexicomp Drug Information: Amlodipine. Wolters Kluwer Health, Inc. • Micromedex Solutions: Amlodipine. Truven Health Analytics, Inc. • FDA Prescribing Information: Norvasc (amlodipine besylate) • Williams B, et al. 2018 ESC/ESH Guidelines for the management of arterial hypertension. Eur Heart J. 2018