Amlodipine

Brand names

• Lotrel [CD]
• Norvasc

Usage

To relieve angina (chest pain associated with heart disease) and to treat hypertension.

How it works

Amlodipine interferes with the movement of calcium into heart muscle cells and the smooth muscle cells in the walls of the arteries. This action relaxes blood vessels (causing them to widen), which lowers blood pressure, increases the blood supply to the heart, and decreases the heart's overall workload.

Side effects

Serious

Increased angina attacks, dizziness upon arising from a sitting or lying position, shortness of breath, weakness, very slow heartbeat.

Common

Headache; flushing in the face and body; water retention causing decreased urination, swelling of the feet and ankles, weight gain.

Less common

Fatigue, dizziness, drowsiness, palpitations, nausea, abdominal pain.

Possible interactions

Other medicaments:

Amlodipine taken concurrently with:

• adenosine (Adenocard) may cause extended problems with slow heart rate.
• amiodarone (Cordarone) may worsen AV block or cause further slowing of the heart in partial atrioventricular (AV) block or sick sinus syndrome.
• azole antifungals (such as fluconazole [Diflucan] or itraconazole [Sporanox]) and imidazoles such as ketoconazole (Nizoral) may lead to toxic amlodipine blood levels.
• beta-blocker medicaments or digitalis preparations may cause heart rate and rhythm problems.
• cyclosporine (Sandimmune) causes increased cyclosporine blood levels and increased risk of toxicity.
• delavirdine (Rescriptor) may cause increased amlodipine levels and toxicity.
• dofetilide (Tikosyn) may cause dofetilide toxicity.
• medicines that inhibit cytochrome P450 3A4 will increase amlodipine blood levels and those that induce 3A4 will decrease amlodipine blood levels.
• NSAIDs or oral anticoagulants such as Coumadin (warfarin) may lead to increased risk of bleeding in the gastrointestinal (GI) tract.
• quinupristin/dalfopristin (Synercid) may cause extended amlodipine effects or toxicity.
• rifampin (Rifater, others) may result in decreased therapeutic benefit of amlodipine.
• ritonavir (Norvir) and probably other protease inhibitors may lead to amlodipine toxicity.

The following medicament may increase the effects of amlodipine:



• cimetidine (Tagamet).

Foods:

This medicine is increased by grapefruit or grapefruit juice. Avoid eating grapefruit for an hour after taking this medicine. Avoid excessive salt intake.

Herbal medicines or minerals:

Ginseng may increase blood pressure, blunting the benefits of this medicine. Eleuthero root, hawthorn, saw palmetto, ma huang, goldenseal and licorice may also cause increased blood pressure. Indian snakeroot, calcium and garlic may help lower blood pressure. Talk to your doctor before adding any herbal medicines.

Alcohol:

Use caution. Alcohol may exaggerate the drop in blood pressure.

Tobacco smoking:

Nicotine may reduce the effectiveness of this medicament.

Marijuana smoking:

Possible reduced effectiveness of this medicament; mild to moderate increase in angina; possible changes in electrocardiogram, confusing interpretation.

Exposure to sun:

Some case reports of phototoxicity have been made. Caution is advised.

Exposure to heat:

Caution is advised. Hot environments can exaggerate the blood-pressure-lowering effects of this medicament. Observe for light-headedness or weakness.

Heavy exercise or exertion:

This medicament may improve your ability to be more active without resulting angina pain. Use caution.

Discontinuation:

Do not stop this medicament abruptly-gradual withdrawal is often prudent. Watch for development of rebound angina.