This medication is used alone or in combination with other drugs to treat high blood pressure (hypertension). Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. Nifedipine belongs to a class of medications known as calcium channel blockers. It works by relaxing blood vessels so blood can flow more easily.

This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

This drug may also be used for certain types of chest pain (angina). It may help to increase your ability to exercise and decrease the frequency of angina attacks. This drug must be taken regularly to be effective. It should not be used to treat attacks of chest pain when they occur. Use other medications (such as sublingual nitroglycerin) to relieve attacks of chest pain as directed by your doctor. Consult your doctor or pharmacist for details.

This drug may also be used for certain blood circulation disorders (Raynaud's syndrome).

Take this medication by mouth on an empty stomach as directed by your doctor, usually once daily. Swallow the tablets whole. Do not crush or chew the tablets. Doing so can release all of the drug at once, increasing the risk of side effects.

Your doctor may gradually increase your dose. Follow your doctor's instructions carefully. Dosage is based on your medical condition and response to treatment.

Avoid eating grapefruit or drinking grapefruit juice while using this medication unless your doctor or pharmacist says you may do so safely. Grapefruit can increase the chance of side effects with this medicine. Ask your doctor or pharmacist for more details.

Use this medication regularly in order to get the most benefit from it. Remember to use it at the same time each day. Keep taking this medication even if you feel well. Most people with high blood pressure do not feel sick.

Do not suddenly stop taking this medication without consulting your doctor. Your condition may become worse when the drug is suddenly stopped. Your dose may need to be gradually decreased.

Tell your doctor if your condition does not get better or if it gets worse (your blood pressure readings remain high or increase).

Headache, dizziness, nausea, flushing, constipation, leg/muscle cramps, or sexual problems may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• swelling of the ankles/feet
• shortness of breath
• unusual weakness/tiredness
• fast/slow/irregular heartbeat
• fainting
• mental/mood changes
• swollen/tender gums
• vision changes

Although this medication is effective in preventing chest pain (angina), some people who already have severe heart disease may rarely develop worsening chest pain or a heart attack after starting this medication or increasing the dose. Get medical help right away if you experience:

• worsening chest pain
• symptoms of a heart attack (such as chest/jaw/left arm pain, shortness of breath, unusual sweating)

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking this medication, tell your doctor or pharmacist if you are allergic to it; or to other calcium channel blockers (such as felodipine, amlodipine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• heart problems (such as heart failure, aortic stenosis)
• liver problems
• kidney problems
• a certain metabolic disorder (porphyria)

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

Nifedipine passes into breast milk. Consult your doctor before breastfeeding.

See also How to Use section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Other medications can affect the removal of nifedipine from your body, which may affect how nifedipine works. Examples include apalutamide, enzalutamide, mitotane, St. John's wort, rifamycins (such as rifabutin, rifampin), drugs used to treat seizures (such as carbamazepine, phenobarbital, phenytoin), among others.

Some products have ingredients that could raise your heart rate or blood pressure. Tell your pharmacist what products you are using, and ask how to use them safely (especially cough-and-cold products, diet aids, or NSAIDs such as ibuprofen/naproxen).

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669. Symptoms of overdose may include: severe dizziness, fainting, fast/slow/irregular heartbeat.

Do not share this medication with others.

Lifestyle changes such as stress reduction programs, exercise, and dietary changes may increase the effectiveness of this medicine. Talk to your doctor or pharmacist about lifestyle changes that might benefit you.

Lab and/or medical tests (such as liver/kidney function, EKG) may be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

Have your blood pressure checked regularly while taking this medication. Learn how to monitor your own blood pressure at home, and share the results with your doctor.

There are different tablet strengths of this medication available. Some tablet strengths may not be used in place of others. Do not change tablet strengths or use a different number of tablets for your dose without consulting your doctor or pharmacist.

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).