What are the side effects of amlodipine (calcium channel blocker)?

Side Effects of Amlodipine

The most common side effects of amlodipine are peripheral edema (leg/ankle swelling), headache, dizziness, and flushing, with edema being dose-dependent and occurring in up to 10.8% of patients at the 10 mg dose. 1

Most Common Adverse Effects

Peripheral Edema (Most Frequent)

• Peripheral edema is the most characteristic side effect of amlodipine, occurring in a dose-dependent manner: 1.8% at 2.5 mg, 3.0% at 5 mg, and 10.8% at 10 mg daily 1
• Women experience significantly higher rates of edema (14.6%) compared to men (5.6%) 1
• This edema results from the vasodilatory action of the drug and can be managed with diuretics 2
• In pediatric populations, generalized edema can occur and resolves with discontinuation of the medication 3

Vasodilatory Side Effects

• Flushing occurs in 0.7% at 2.5 mg, 1.4% at 5 mg, and 2.6% at 10 mg, with women experiencing higher rates (4.5%) than men (1.5%) 1
• Dizziness affects 1.1% to 3.4% of patients across dosing ranges 1
• Headache is noted as a common adverse effect related to vasodilation 2, 4
• Palpitations occur in 0.7% to 4.5% of patients in a dose-dependent manner, more frequently in women (3.3%) than men (1.4%) 1

Other Common Side Effects (>1% Incidence)

• Fatigue: 4.5% of patients (compared to 2.8% with placebo) 1
• Nausea: 2.9% of patients 1
• Abdominal pain: 1.6% of patients 1
• Somnolence: 1.4% of patients, slightly higher in women 1

Less Common but Clinically Important Side Effects (<1% but >0.1%)

Cardiovascular

• Arrhythmias (including ventricular tachycardia and atrial fibrillation), bradycardia, chest pain, syncope, tachycardia 1

Neurological

• Hypoesthesia, peripheral neuropathy, paresthesia, tremor, vertigo 1

Gastrointestinal

• Constipation, dysphagia, diarrhea, flatulence, pancreatitis, vomiting, gingival hyperplasia 1

Musculoskeletal

• Muscle cramps, myalgia, arthralgia 1

Dermatologic

• Angioedema, erythema multiforme, pruritus, various rashes 1

Other Systems

• Sexual dysfunction, insomnia, nervousness, depression, dyspnea 1

Important Clinical Considerations

Discontinuation Rate

• Only approximately 1.5% of patients discontinue amlodipine due to adverse reactions, which is not significantly different from placebo 1
• Amlodipine is generally well tolerated at doses up to 10 mg daily 1, 5

Laboratory Parameters

• No clinically significant changes occur in serum potassium, glucose, triglycerides, cholesterol, uric acid, blood urea nitrogen, or creatinine 1
• Unlike some antihypertensive agents, amlodipine does not adversely affect serum lipid or glucose levels 5, 6

Special Populations

• In pediatric patients, adverse effects include dizziness, fatigue, flushing, and leg edema, all of which improve with dose reduction 7
• A small, clinically insignificant increase in heart rate may occur in children (from 91 to 99 beats/min) 7

Critical Safety Points

When to Avoid or Use with Caution

• Do not use if allergic to amlodipine or any inactive ingredients 1
• In patients with heart failure, amlodipine may precipitate or worsen symptoms, though it was shown safe in the PRAISE trial for nonischemic dilated cardiomyopathy 2
• Systemic hypotension can occur, potentially causing reflex tachycardia, sympathetic stimulation, and right ventricular ischemia 2

Rare but Serious Effects

• Gynecomastia has been reported infrequently in postmarketing surveillance 1
• Hematologic effects including leukopenia, purpura, and thrombocytopenia are rare 1

Drug-Specific Advantages

• Amlodipine does not cause cardiac conduction disturbances or postural hypotension, unlike some other cardiovascular agents 6
• No clinically important drug interactions have been observed 5
• The long half-life (35-50 hours) provides continuous protection even if a dose is missed 8