Nifedipine

Brand names

• Adalat
• Adalat CC
• Adalat FT
• Adalat PA
• Adalat XL
• Apo-Nifed
• Apo-Nifed PA
• Gen-Nifedipine
• Nifedipine PA
• Novo-Nifedin
• Nu-Nifed
• Nu-Nifedipine-PA
• Procardia
• Procardia XL

Usage

To treat high blood pressure and to prevent attacks of angina pectoris (chest pain associated with coronary artery disease).

How it works

Nifedipine 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

Breathing difficulty, coughing, or wheezing; irregular or pounding heartbeat; chest pain; fainting. Get medical help immediately.

Common

Headache; dizziness; skin flushing and feeling of warmth; swelling in the feet, ankles, or calves; palpitations.

Less common

Constipation or diarrhea, nausea, heartburn, unusual fatigue and weakness, skin rash, increased urination, vision problems.

Possible interactions

Other medicaments:

Nifedipine taken concurrently with:

• amiodarone (Cordarone) may cause the heart to stop.
• 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.
• cyclosporine (Sandimmune) can lead to nifedipine toxicity.
• digoxin (Lanoxin) may lead to digoxin toxicity.
• diltiazem (Cardizem) may lead to nifedipine toxicity.
• magnesium can cause additive lowering of the blood pressure.
• oral antidiabetic medicaments or insulin may result in loss of glucose control.
• phenytoin (Dilantin) or fosphenytoin (Cerebyx) can cause phenytoin or fosphenytoin toxicity.
• quinupristin/dalfopristin (Synercid) can cause nifedipine toxicity.
• rifampin (Rifadin) can decrease nifedipine's effectiveness.
• tacrolimus (Prograf) may lead to tacrolimus toxicity.
• theophylline can reduce the therapeutic benefits of nifedipine and may lead to theophylline toxicity as well.
• vincristine (Oncovin) can cause vincristine toxicity.

The following medicaments may increase the effects of nifedipine:



• some antifungals (fluconazole, itraconazole and ketoconazole)-may increase nifedipine blood levels and lead to toxicity.
• cimetidine (Tagamet).
• quinidine (Quinaglute, others)-can lead to nifedipine toxicity as well as decreased quinidine effectiveness.
• ranitidine (Zantac).
• ritonavir (Norvir) and other protease inhibitors.

Foods:

Do not eat grapefruit for an hour after taking this medicine. It is also prudent to 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 ephedra should be avoided by people living with hypertension. St. John's wort and nifedipine can increase sun sensitivity. Caution is advised. Talk with your doctor before adding any herbal medicine to nifedipine.

Beverages:

Grapefruit juice may greatly increase the absorption (bioavailability) of nifedipine and result in an exaggerated therapeutic effect. Water is the best liquid to take this medicine with.

Alcohol:

Alcohol may exaggerate the drop in blood pressure experienced by some people.

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:

Caution-rare cases of phototoxicity have been reported.

Exposure to heat:

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 and avoid excessive exercise that could impair heart function in the absence of warning pain.

Discontinuation:

Do not stop this medicament abruptly. Consult your physician regarding gradual withdrawal. Observe for the possible development of rebound angina.