Medication · Cardiovascular · full clinical detail
Amlodipine
A long-acting calcium channel blocker that relaxes artery walls to lower blood pressure and prevent angina, taken once daily and among the most prescribed medicines worldwide.
Amlodipine relaxes the muscle in the walls of your arteries so that they widen. Blood flows through them with less resistance, which lowers blood pressure and lets more blood reach the heart muscle, which helps prevent angina.
NICE first-line choice for adults aged 55 or over and for adults of Black African or African-Caribbean family origin of any age, and the usual second agent added to an ACE inhibitor or ARB
Licensed indications come from the product licence in the named country; guideline-supported and off-label uses are cited to the guideline that supports them. Licensing differs between countries.
How it works
Amlodipine relaxes the muscle in the walls of your arteries so that they widen. Blood flows through them with less resistance, which lowers blood pressure and lets more blood reach the heart muscle, which helps prevent angina.
Blocks L-type calcium channels in the smooth muscle of artery walls. Muscle cells need calcium to contract, so with fewer channels open the arteries relax and widen, lowering resistance and blood pressure and letting more blood reach heart muscle. Amlodipine selects vessels over heart muscle, so it does not slow the heart; its long half-life gives smooth 24-hour control.
Mechanism of action
Amlodipine is a dihydropyridine that binds the alpha-1 subunit of L-type voltage-gated calcium channels in vascular smooth muscle, preferring the inactivated channel state that predominates in depolarised arterial muscle. Reduced calcium influx lowers activation of myosin light-chain kinase, so arteriolar tone and total peripheral resistance fall while cardiac contractility and sinoatrial and atrioventricular conduction are little affected at therapeutic doses (in contrast to verapamil and diltiazem). Coronary arteries and arterioles dilate, improving oxygen delivery in chronic stable and vasospastic angina. The slow onset and long elimination half-life (35-50 hours) give gradual, sustained 24-hour blood-pressure control without reflex tachycardia.
Ankle swelling (fluid leaking from widened capillaries, not heart failure; not helped by diuretics)
Flushing, headache, palpitations in the first weeks
Gum overgrowth, tiredness, dizziness
Serious: seek help
Marked low blood pressure with fainting, particularly with other blood-pressure medicines or dehydration
Chest pain that is new or worse in the first days of treatment (rare reflex tachycardia)
Allergic reaction: swelling of the face, lips or throat, difficulty breathing
Yellowing of the skin or eyes (rare liver reaction)
Source: NHS: Amlodipine. Frequencies follow the source's categories; no percentages are invented.
Serious safety information
Special warning. Amlodipine may be prescribed with care, or a different medicine chosen, for people with severe heart failure, because dihydropyridines can worsen fluid retention in some patients; the BNF lists heart failure among its cautions. UK
Warnings and precautions
Driving. Dizziness, particularly when standing up, is common in the first weeks; UK information advises not driving, cycling or using tools or machinery if affected. UK
Liver. Amlodipine is cleared by the liver; in hepatic impairment the half-life is prolonged and a lower starting dose is advised, with slow titration in severe impairment. UK
Precaution. Ankle swelling is a dose-related effect of dihydropyridines caused by widened capillaries, not by heart failure, and does not respond to diuretics; it is a reason to review the dose rather than to add a water tablet. UK
Contraindications
Factor
Detail
Strength
Country · source
Cardiogenic shock
Amlodipine is contraindicated in cardiogenic shock.
"Absolute" and "relative" follow the wording of the cited source; where the source does not classify, the cell is blank.
Interactions
Check interactions
Taking Amlodipine with other medicines? Add them to the checker to see what the official sources say about each pair: the mechanism, general management and monitoring, never a bare "safe".
Interactions documented in the official sources cited on each card. The list covers the medicines represented on this site and is not exhaustive; how the interaction data is compiled.
Other medicines
Amlodipine + Simvastatin
ModerateMonitoring or dose adjustment advised
Amlodipine raises simvastatin blood levels, increasing the risk of muscle damage (myopathy and rhabdomyolysis).
Why it can occur
CYP inhibition · Amlodipine is a weak CYP3A4 inhibitor; simvastatin exposure roughly doubles
What official information says
UK information states the doctor may prescribe a lower dose of simvastatin (usually no more than 20 mg a day) for someone taking amlodipine.
What to discuss with a clinician
Official UK information: simvastatin dose limited to 20 mg daily with amlodipine; report unexplained muscle pain.
What may be monitored
Muscle symptoms · Creatine kinase if symptoms
Basis of the status
NHS: Taking amlodipine with other medicines (simvastatin dose limited to 20 mg)
Amlodipine + Erythromycin, azole antifungals and other strong CYP3A4 inhibitors
Severity not gradedInteraction documented
Clarithromycin, erythromycin, itraconazole, ketoconazole and some HIV medicines raise amlodipine levels, increasing dizziness, low blood pressure and ankle swelling.
Why it can occur
CYP inhibition
What official information says
UK information lists these among medicines that can interfere with the way amlodipine works and advises telling a doctor.
What to discuss with a clinician
Documented in official information; the prescriber may adjust the amlodipine dose or monitor blood pressure during the course.
Grapefruit inhibits intestinal CYP3A4 and can raise amlodipine levels, increasing dizziness, flushing and ankle swelling; the effect is smaller than with some other calcium channel blockers but UK information advises against large amounts. (CYP inhibition)
UK information advises not eating or drinking large amounts of grapefruit or grapefruit juice while taking amlodipine. UK
Alcohol
Alcohol adds to the blood-pressure-lowering effect and can make dizziness and light-headedness worse, particularly in the first weeks. (Additive vasodilation and hypotension)
UK information states alcohol can be drunk in moderation but may make dizziness worse; stopping to check how the medicine affects you first is advised. UK
Monitoring
What
Why
Tests and markers
Source
Blood pressure
To confirm the dose is controlling blood pressure and is not causing symptomatic hypotension; home or clinic readings
UK information states that amlodipine is not usually recommended in pregnancy but may be prescribed when a doctor judges the benefit outweighs the risk; other medicines are usually preferred for blood pressure in pregnancy, and a woman who becomes pregnant should not stop it without advice. UK
Breastfeeding
Small amounts pass into breast milk; UK information states amlodipine can usually be taken while breastfeeding when the baby is healthy and a doctor agrees, with a review for drowsiness or poor feeding in the baby. UK
Children
Licensed in the UK for hypertension in children aged 6 to 17 years at specialist-guided doses; not for younger children outside specialist care. UK
Older adults
Older adults are more sensitive to blood-pressure lowering and to ankle swelling; a lower starting dose is often used and titrated slowly. UK
Kidney impairment
Amlodipine is not removed by dialysis and no dose adjustment is needed in kidney impairment; it is a usual choice when ACE inhibitors or ARBs raise potassium or creatinine. UK
Liver impairment
Half-life is prolonged in liver disease; start with a low dose and increase slowly, particularly in severe hepatic impairment. UK
In heart failure with reduced ejection fraction amlodipine is neutral for survival but may worsen oedema; it is used with care when blood pressure control is needed.
Educational summary of drug–condition cautions in the cited sources; not a personal screening.
Effects on tests and results
Kidney function tests: Amlodipine has no meaningful direct effect on routine blood tests; blood pressure is the measure of effect. Kidney function and potassium are checked because amlodipine is usually combined with an ACE inhibitor, ARB or diuretic that does affect them. UK
Pharmacokinetics
Absorption
Well absorbed orally (bioavailability about 64-80%); food does not affect absorption
Peak
6-12 hours after a dose
Half-life
35-50 hours; steady state after 7-8 days of once-daily dosing
Metabolism
Extensively metabolised by the liver (CYP3A4) to inactive metabolites
Elimination
Metabolites mainly in urine; about 10% unchanged drug; not removed by dialysis
Dosing is intentionally not described: doses depend on the indication, the country's licence, kidney and liver function, age, weight and other medicines, and are set by a prescriber.
Medicines that share the class of Amlodipine. They are separate medicines with their own licences, doses and interactions, not alternative names for Amlodipine.
Medicines often discussed alongside Amlodipine: used together, compared with it, or acting on the same problem by a different route.
Educational content. Anatomy Nexus provides medical education and does not replace professional medical advice, diagnosis, treatment, prescribing or pharmacist review. Doses, choices and monitoring are decided by a prescriber for an individual; never start, stop or change a medicine on the basis of this page.
