Felodipine

Brand names

• Lexxel [CD]
• Logimax [CD]
• Plendil
• Renedil

Usage

To control high blood pressure (hypertension).

How it works

Felodipine 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

Irregular or slow heartbeat, low blood pressure (causing dizziness or faintness).

Common

Flushing or skin rash, headache, swelling of the lower legs or feet.

Less common

Dizziness, numbness or tingling sensation, chest pain, palpitations, weakness, runny nose, rapid pulse, sore throat, abdominal discomfort, nausea, constipation or diarrhea, cough, muscle cramps, back pain, overgrowth of the gums.

Possible interactions

Other medicaments:

Felodipine taken concurrently with:

• adenosine may result in an extended slowing of the heart.
• amiodarone (Cordarone) may lead to slowing of heart rate or worsening atrioventricular (AV) block if both medicaments are used in people with partial AV block or "sick sinus" syndrome.
• beta-blocker medicaments or digitalis preparations may affect heart rate and rhythm adversely. Careful monitoring by your physician is necessary if these medicaments are taken concurrently.
• carbamazepine (Tegretol) may decrease felodipine benefits.
• cyclosporine (Sandimmune) may change levels of either medicament.
• delavirdine (Rescriptor) may lead to felodipine toxicity.
• digoxin (Lanoxin) may increase digoxin levels and result in toxicity.
• itraconazole, fluconazole or ketoconazole may lead to felodipine toxicity.
• magnesium (particularly in high doses) may cause low blood pressure (not specifically reported for felodipine, but another medicament in the calcium channel-blocker class does this).
• nonsteroidal anti-inflammatory medicaments (NSAIDs) or oral anticoagulants (Coumadin) may increase risk of stomach or intestinal (Gl) bleeding.
• phenobarbital can cause decreased felodipine benefits.
• phenytoin (Dilantin) or fosphenytoin (Cerebyx) may cause decreased phenytoin or fosphenytoin levels.
• quinupristin/dalfopristin (Synercid) may lead to felodipine toxicity.
• rifampin (Rifadin) may cause decreased felodipine benefits (reported with other calcium channel blockers).
• ritonavir (Norvir) and perhaps other protease inhibitors may lead to toxicity.
• theophylline (Theo-Dur, others) may lower theophylline levels requiring theophylline dose changes.

The following medicaments may increase the effects of felodipine:

• cimetidine (Tagamet).
• erythromycin-may also occur with other macrolide antibiotics since they are structurally similar.

Foods:

Avoid eating grapefruit for 1 hour after taking this medicine. Avoid excessive salt intake.

Herbal medicines or minerals:

Ginseng may increase blood pressure, blunting the benefits of these medicines. Hawthorn, saw palmetto, ma huang, goldenseal, yohimbe and licorice may also increase blood pressure. Calcium and garlic may help lower blood pressure. Indian snakeroot has a German Commission E monograph indication for hypertension:-talk to your doctor. Eleuthero root and ma huang should be avoided by people living with hypertension.

Beverages:

Grapefruit juice can cause a serious increase in the absorption of this medicament-levels may be increased by over 400%. Do not take this medicament with grapefruit juice. May be taken with milk or water.

Alcohol:

Use with caution-alcohol may exaggerate the drop in blood pressure experienced by some people.

Tobacco smoking:

Nicotine may reduce effectiveness.

Exposure to heat:

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

Discontinuation:

Do not stop this medicament abruptly. Ask your physician about gradual withdrawal. Watch for development of rebound hypertension.

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