Pharmacology · Calcium channel blockers
Amlodipine !
A long-acting calcium channel blocker that relaxes arteries. Used for high blood pressure and angina; ankle swelling is its best-known side effect.
Updated 2026-11-01
The figure shows amlodipine bound to the human CaV1.2 channel (the structure also contains the toxin calciseptine and the drug pinaverium).
Mechanism of action
Amlodipine is a dihydropyridine that binds the L-type calcium channel of vascular smooth muscle and keeps fewer channels open, so less calcium enters and the arterioles relax. Peripheral resistance and blood pressure fall; in angina it lowers afterload and relieves coronary spasm. It binds and leaves the channel slowly, so its effect builds up gradually.
- Amlodipine binds the L-type calcium channel in arteriolar muscle
- Less calcium enters the smooth muscle cell
- Arterioles relax and peripheral resistance falls
- Blood pressure and cardiac afterload fall
Pharmacokinetics
- Absorption
- Absorbed slowly by mouth; food does not change it
- Metabolism
- Extensively metabolised in the liver; CYP3A inhibitors raise its levels
- Half-life
- Terminal half-life about 30 to 50 hours, longer in liver impairment
- Onset and duration
- Gradual onset, so sudden hypotension is unlikely
Indications
- High blood pressure Arterial hypertension →
- Chronic stable angina Stable angina →
- Vasospastic (Prinzmetal) angina
Adverse effects
Common
- Ankle and leg oedema, dose-related
- Flushing
- Headache
- Palpitations
- Dizziness and fatigue
Contraindications
- Known hypersensitivity to amlodipine
Key interactions
- Strong or moderate CYP3A4 inhibitors (for example clarithromycin, itraconazole, ritonavir)
- Higher amlodipine levels and more hypotension and oedema
- Simvastatin
- Higher simvastatin exposure and myopathy risk; the statin is limited
- Cyclosporine or tacrolimus
- Higher immunosuppressant levels; trough levels are watched
What is monitored
- Blood pressure
- Heart rate
- Oedema
- Angina symptoms when starting
Administration and safety
- Given by mouth once a day; tablets work the same with or without food
- Several «-dipine» names look and sound alike (nifedipine, nimodipine, nicardipine): the name is checked on every order
Nursing care
- Check blood pressure and heart rate before and after starting
- Look for ankle oedema and ask about headache and flushing
- In coronary disease, ask about new or worse chest pain in the first weeks
- Teach the patient that the full effect takes days to build up and not to stop it on their own
Pregnancy and breastfeeding
Human data are limited; it is used in pregnancy only when the benefit justifies it, and other agents with more experience are usually preferred.
Test yourself
Think of the answer, then tap the question to see it.
Why is sudden hypotension unusual after amlodipine?
It binds and leaves the calcium channel slowly and has a long half-life, so its effect builds up gradually over days.
What is the most common adverse effect of amlodipine?
Dose-related peripheral oedema (ankles), from arteriolar dilation.
Which statin interaction is classic with amlodipine?
Simvastatin: amlodipine raises its exposure and the risk of myopathy, so the simvastatin is limited.
Does amlodipine slow AV conduction like verapamil?
No. As a dihydropyridine it acts mainly on arteries and has little effect on the sinus and AV nodes.
Related drugs
Related conditions
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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - AMLODIPINE BESYLATE tablet (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); eEML - Electronic Essential Medicines List (World Health Organization, 2025).
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Representative model, for educational purposes only.