Amlodipine is a dihydropyridine calcium channel blocker medication commonly used for the treatment of hypertension, angina and coronary artery disease. It has been approved for use since 1990 and is on the WHO’s List of Essential Medicines. It is used alone or as a combination medication. The original brand name was Norvasc, but Pfizer’s patent protection on it ended in 2007, so it is now available under a number of brand names.
Amlodipine is an angioselective calcium channel blocker that inhibits the movement of calcium ions influx across cell membranes in vascular smooth muscle cells and cardiac muscle cells to inhibit cardiac muscle and vascular smooth muscle cells contraction. This results in vasodilation and a reduction in peripheral vascular resistance, thus lowering blood pressure. In cardiac muscle this also prevents excessive constriction in the coronary arteries.
The dihydropyridine calcium channel blockers are more selective for the peripheral blood vessels so are associated with a lower incidence of cardiac abnormalities than other types of calcium channel blockers.
Amlodipine is metabolized in the liver. The highest availability of action is 6–12 hours after an oral dose with a duration of action of at least 24 hours and an estimated half-life of 30–50 hours. It is excreted in the urine.
Vasodilatory effects: peripheral oedema, dizziness, palpitations, and flushing.
Feeling tired (somnolence), abdominal pain, headache, and nausea.
Serious: hypotension, myocardial infarction.
Uncommon: blood disorders, impotence, depression, peripheral neuropathy, insomnia, tachycardia, gingival enlargement, hepatitis, and jaundice
Chemical formula: C20H25ClN2O5
Brand names: Norvasc (Pfizer), Katerzia (Azurity), Aforbes (Merck) and many others
Amlodipine is notorious for causing ankle/foot oedema – up to 10%; It is 3 times more likely in females than males. This oedema may be alleviated by using in combination with an ACE inhibitor.
Peripheral neuropathy is an uncommon side effect.
Other calcium channel blockers:
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