amlodipine, Norvasc

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GENERIC NAME: amlodipine besylate

BRAND NAME: Norvasc

DRUG CLASS AND MECHANISM: Amlodipine belongs to a class of medications called calcium channel blockers (CCBs). These medications block the transport of calcium into the smooth muscle cells lining the arteries of the heart (coronary arteries) and other arteries of the body. Since the action of calcium is important for muscle contraction, blocking calcium transport relaxes arterial muscles and expands (dilates) coronary arteries and other arteries of the body. By dilating coronary arteries, amlodipine increases the flow of blood to the heart and is useful in preventing heart pain (angina) resulting from reduced flow of blood to the heart caused by coronary artery spasm (contraction). Relaxing the muscles lining the arteries in the rest of the body lowers blood pressure, which reduces the work that the heart must do to pump blood to the body. Reducing the work of the heart also lessens the heart muscle's need for oxygen, and thereby further helps to prevent angina in patients with coronary artery disease. The FDA approved amlodipine in July 1992.

PRESCRIPTION: Yes

GENERIC AVAILABLE: Yes

PREPARATIONS: Tablets: 2.5, 5, and 10 mg

STORAGE: Amlodipine should be stored at room temperature in a tight, light resistant container.

PRESCRIBED FOR: Chest pain or heart pain (angina) occurs because of insufficient oxygen delivered to the heart muscles. Insufficient oxygen may be a result of coronary artery blockage or spasm, or because of exertion which increases the need of the heart for oxygen in patients with coronary artery narrowing (coronary artery disease or atherosclerosis). Amlodipine is used for the treatment and prevention of angina resulting from coronary spasm as well as from exertion. Amlodipine also is used in the treatment of high blood pressure.

DOSING: The recommended starting dose of amlodipine for children and adults is 2.5 to 5 mg once daily. The maximum dose for adults is 10 mg once daily and the maximum dose for children is 5 mg once daily. Amlodipine can be taken with or without food. Amlodipine is inactivated mainly by the liver, and dosages may need to be lowered in patients with liver dysfunction.

DRUG INTERACTIONS: Combining amlodipine with sildenafil (Viagra) and similar drugs used for treating erectile dysfunction may lead to excessive reductions in blood pressure with complications, particularly fainting upon standing (orthostatic hypotension).

Amlodipine significantly increases blood levels of simvastatin (Zocor). The dose of simvastatin should be limited to 20 mg daily by patients taking amlodipine.

Ketoconazole (Nizoral, Extina, Xolegel, Kuric), itraconazole (Sporanox), ritonavir (Norvir) and other drugs that are strong inhibitors of amlodipine inactivation in the liver increase blood levels of amlodipine, resulting in excessive blood pressure reduction.

PREGNANCY: Generally, amlodipine is avoided in pregnancy, and by nursing mothers and children although there are no adequate studies of amlodipine use during pregnancy.

NURSING MOTHERS: It is not known whether amlodipine is excreted in breast milk. Generally, amlodipine is avoided in pregnancy, and by nursing mothers and children.

SIDE EFFECTS: Side effects of amlodipine are generally mild and reversible. The two most common side effects are headache and edema (swelling) of the lower extremities. Less common side effects include dizziness, flushing, fatigue, nausea, and palpitations.




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