Isradipine (patient information)

Why this medication is prescribed

Isradipine is used to treat high blood pressure. It relaxes your blood vessels so your heart does not have to pump as hard.

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

How this medication should be used

Isradipine comes as a regular capsule and an extended-release (long-acting) tablet to take by mouth. The capsule is usually taken two times a day, while the tablet is usually taken once a day. The tablet should be swallowed whole. Do not chew, divide, or crush the tablet. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take isradipine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Isradipine controls high blood pressure but does not cure it. Continue to take isradipine even if you feel well. Do not stop taking isradipine without talking to your doctor.

Special precautions

Before taking isradipine:

• tell your doctor and pharmacist if you are allergic to isradipine or any other drugs.
• tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially cimetidine (Tagamet), fentanyl (Duragesic), heart and blood pressure medications such as beta-blockers and diuretics ('water pills'), medications to treat glaucoma (increased pressure in the eye), ranitidine (Zantac), rifampin (Rifadin, Rimactane), and vitamins.
• tell your doctor if you have or have ever had heart, liver, or kidney disease or a history of gastrointestinal obstruction (strictures).
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking isradipine, call your doctor.
• if you are having surgery, including dental surgery, tell your doctor or dentist that you are taking isradipine.

Special dietary instructions

Talk to your doctor about drinking grapefruit juice or eating grapefruit while taking isradipine.

Talk to your doctor before using salt substitutes containing potassium. If your doctor prescribes a low-salt or low-sodium diet, follow these directions carefully.

What to do if you forget a dose

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Side Effects

Minor Side Effects

Isradipine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• headache
• dizziness or lightheadedness
• flushing (feeling of warmth)
• fast heartbeat
• excessive tiredness
• upset stomach
• vomiting
• diarrhea

Severe Side Effects

If you experience any of the following symptoms, call your doctor immediately:

• chest pain
• swelling of the face, eyes, lips, tongue, arms, or legs
• difficulty breathing or swallowing
• fainting
• rash

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at http://www.fda.gov/MedWatch/report.htm] or by phone [1-800-332-1088].

Storage conditions needed for this medication

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

In case of emergency/overdose

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

Other information

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

The extended-release tablet does not dissolve in the stomach after being swallowed. It slowly releases medicine as it passes through your small intestines. It is not unusual to see the tablet shell in the stool.

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

Brand names

• DynaCirc®
• DynaCirc® CR®