Side Effects of Amlodipine
The most common side effects of amlodipine are peripheral edema and headache, with edema occurring in approximately 10-15% of patients at standard doses, though importantly, about one-third of edema cases may be unrelated to the drug itself. 1, 2
Common Side Effects (Dose-Related)
The following side effects occur more frequently with higher doses and show clear dose-response relationships 3, 4, 1:
Peripheral Edema:
- 2.5 mg: 1.8%
- 5 mg: 3.0%
- 10 mg: 10.8%
- Women experience edema more frequently than men (14.6% vs 5.6%) 1
- Placebo-adjusted rate is 63%, meaning 37% of edema cases are unrelated to amlodipine 2
- Risk ratio vs placebo: 2.9 (95% CI: 2.50-3.36) 2
Other Common Dose-Related Effects:
- Headache: 2-3% (actually reduced vs placebo at low/medium doses) 1, 2
- Dizziness: 1.1-3.4% 1
- Flushing: 0.7-2.6% (more common in women: 4.5% vs 1.5% in men) 1
- Palpitations: 0.7-4.5% (more common in women: 3.3% vs 1.4% in men) 1
Additional Common Side Effects (>1%)
- Fatigue: 4.5%
- Nausea: 2.9%
- Abdominal pain: 1.6%
- Somnolence: 1.4%
Less Common but Important Side Effects (<1% but >0.1%)
Cardiovascular: Arrhythmia (including ventricular tachycardia and atrial fibrillation), bradycardia, chest pain, peripheral ischemia, syncope, tachycardia, vasculitis
Gastrointestinal: Constipation, gingival hyperplasia, pancreatitis, dysphagia
Neurological: Paresthesia, tremor, vertigo, peripheral neuropathy
Dermatologic: Angioedema, erythema multiforme, pruritus, rash
Hematologic: Leukopenia, purpura, thrombocytopenia
Other: Gynecomastia (postmarketing), sexual dysfunction
Serious/Life-Threatening Side Effects
In overdose situations:
- Distributive shock requiring vasopressor support
- Noncardiogenic pulmonary edema
- Acute hypoxic respiratory failure
- Severe hypotension
- Bradycardia and AV block
Key Clinical Considerations
Contraindications and Cautions:
- Avoid in heart failure with reduced ejection fraction (HFrEF) unless specifically indicated, though amlodipine is reasonably well tolerated in mild LV dysfunction 3, 4, 7
- Do not use immediate-release nifedipine without beta-blocker, but amlodipine is safer due to its long half-life 3, 4
- Avoid verapamil and diltiazem in severe LV dysfunction, but amlodipine may be used 7, 8
Metabolic Effects:
- Metabolically neutral: No clinically significant changes in serum glucose, lipids, potassium, or renal function 1, 9
- Some disproportionality reports suggest hyperglycemia signals, but T2DM reports are less frequent than with comparators 10
Advantages Over Other Calcium Channel Blockers:
- Lower incidence of side effects compared to nifedipine retard (27% vs 41%, p<0.05) 11
- Significantly fewer reports of headache and flushing than nifedipine 11
- No constipation (unlike verapamil) 12
- No bradycardia or AV block (unlike diltiazem/verapamil) 3, 4
Dose-Dependent Strategy:
- Start with 2.5-5 mg to minimize edema risk 2
- Low/medium doses (2.5-5 mg) have lower edema rates (RR: 2.01) vs 10 mg (RR: 3.08) 2
- Discontinuation rate due to adverse effects is only ~1.5%, similar to placebo 1
Special Populations:
- Well tolerated in elderly patients 1, 12
- No dosage adjustment needed in renal impairment 1, 12
- Dosage adjustment may be needed in hepatic impairment 12
- Avoid in pregnancy 1
The long half-life (35-50 hours) provides continuous BP control even with missed doses, reducing risk from incidental noncompliance 9.