Nifedipine is in a group of drugs called calcium channel blockers. It works by relaxing the muscles of your heart and blood vessels.

Nifedipine is used to treat hypertension (high blood pressure) and angina (chest pain).

Nifedipine may also be used for purposes not listed in this medication guide.

What is the most important information I should know about nifedipine?

You should not use nifedipine if you have severe coronary artery disease, or if you have had a heart attack within the past 2 weeks.

Before taking nifedipine, tell your doctor if you have kidney or liver disease, a blockage in your digestive tract (stomach or intestines), a history of stomach surgery, coronary artery disease, underactive thyroid, diabetes, or congestive heart failure.

If you need surgery, tell the surgeon ahead of time that you are using nifedipine. You may need to stop using the medicine for a short time.

Do not stop taking nifedipine without first talking to your doctor, even if you feel fine. Stopping suddenly may make your condition worse. High blood pressure often has no symptoms. You may need to use blood pressure medication for the rest of your life.

Nifedipine comes as a capsule and an extended-release (long-acting) tablet to take by mouth. The capsule is usually taken three or four times a day. The extended-release tablet should be taken once daily on an empty stomach, either 1 hour before or 2 hours after a meal. To help you remember to take nifedipine, take it at around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take nifedipine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the extended-release tablets whole; do not split, chew, or crush them.

Your doctor will probably start you on a low dose of nifedipine and gradually increase your dose, generally once every 7 to 14 days.

If taken regularly, nifedipine controls chest pain, but it does not stop chest pain once it starts. Your doctor may prescribe a different medication to take when you have chest pain.

Nifedipine controls high blood pressure and chest pain (angina) but does not cure them. Continue to take nifedipine even if you feel well. Do not stop taking nifedipine without talking to your doctor. Your doctor will probably decrease your dose gradually.

Take nifedipine exactly as prescribed by your doctor. Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not take this medicine in larger or smaller amounts or for longer than recommended.

You may need to take an extended-release tablet on an empty stomach. Follow the directions on your medicine label about taking this medication with or without food.

Do not crush, chew, or break a nifedipine extended-release tablet. Swallow it whole.

Your blood pressure will need to be checked often and you may need other blood tests at your doctor's office.

Some tablet forms of nifedipine are made with a shell that is not absorbed or melted in the body. Part of the tablet shell may appear in your stool. This is a normal side effect of nifedipine and will not make the medication less effective.

If you need surgery, tell the surgeon ahead of time that you are using nifedipine. You may need to stop using the medicine at least 36 hours before surgery.

You may have very low blood pressure while taking this medication. Call your doctor if you are sick with vomiting or diarrhea, or if you are sweating more than usual.

If you are also taking a beta-blocker (atenolol, carvedilol, labetalol, metoprolol, nadolol, nebivolol, propranolol, sotalol, and others) you should not stop using the beta-blocker suddenly or you could have serious heart problems that will not be prevented by nifedipine. Follow your doctor's instructions about tapering your beta-blocker dose.

You should not stop using nifedipine suddenly. Stopping suddenly may make your condition worse.

If you are being treated for high blood pressure, keep using this medication even if you feel well. High blood pressure often has no symptoms. You may need to use blood pressure medication for the rest of your life.

Store at room temperature away from moisture, heat, and light.

You should not use this medicine if you are allergic to nifedipine, if you have severe coronary artery disease, or if you have had a heart attack within the past 2 weeks.

To make sure nifedipine is safe for you, tell your doctor if you have:

• severe COPD (chronic obstructive pulmonary disease);

• kidney disease;

• congestive heart failure; or

• if you take other medications, especially an antibiotic or antifungal medicine, an antidepressant, heart or blood pressure medicine, or drugs to treat HIV/AIDS or hepatitis C.

It is not known whether nifedipine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication.

Nifedipine can pass into breast milk and may harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

The nifedipine extended-release tablet may contain lactose. Talk to your doctor before using this form of nifedipine if you have galactose intolerance, or severe problems with lactose (milk sugar).

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature, away from light, and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

Do not drink grapefruit juice or eat grapefruit 3 days before and while taking nifedipine.

If your doctor prescribes a low-salt or low-sodium diet, follow these directions carefully.

Grapefruit and grapefruit juice may interact with nifedipine and lead to unwanted side effects. Discuss the use of grapefruit products with your doctor.

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy. Get up slowly and steady yourself to prevent a fall.

Get emergency medical help if you have any signs of an allergic reaction to nifedipine: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

• worsening angina;

• a light-headed feeling, like you might pass out;

• pounding heartbeats or fluttering in your chest;

• chest pain or heavy feeling, pain spreading to the jaw or shoulder, nausea, sweating, general ill feeling;

• swelling in your ankles or feet; or

• upper stomach pain, jaundice (yellowing of the skin or eyes).

Common nifedipine side effects may include:

• mild dizziness;

• flushing (warmth, redness, or tingly feeling);

• weakness, headache, mood changes;

• heartburn, nausea;

• tremors, muscle cramps; or

• cough, wheezing, sore throat, stuffy nose.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Other drugs may interact with nifedipine, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Keep all appointments with your doctor and the laboratory. Your blood pressure should be checked regularly to determine your response to nifedipine.

If you are taking certain extended-release tablets (Afeditab CR, Procardia XL), you may notice something that looks like a tablet in your stool. This is just the empty tablet shell, and this does not mean that you did not get your complete dose of medication.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.