Diltiazem is used to treat high blood pressure and to control chest pain (angina). Diltiazem is in a class of medications called calcium-channel blockers. It works by relaxing the blood vessels so the heart does not have to pump as hard. It also increases the supply of blood and oxygen to the heart.

Diltiazem is also used sometimes to treat Raynaud's syndrome. Talk to your doctor about the possible risks of using this drug for your condition.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Special precautions

Before taking diltiazem,

• Tell your doctor and pharmacist if you are allergic to diltiazem or any other drugs.

• Tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially heart and blood pressure medications such as beta-blockers, medications to treat depression; medications to treat glaucoma (increased pressure in the eye); theophylline; and vitamins.

• Tell your doctor if you have or have ever had heart, liver, or kidney disease.

• Tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking diltiazem, call your doctor.

• If you are having surgery, including dental surgery, tell your doctor or dentist that you are taking diltiazem.

Side effects

Although side effects from diltiazem are not common, they can occur. Tell your doctor if any of these symptoms are severe or do not go away:

• dizziness or lightheadedness

• flushing (feeling of warmth)

• headache

• excessive tiredness

• slower heartbeat

• upset stomach

• loss of appetite

• vomiting

• diarrhea

• constipation

• stomach pain

• dry mouth

• difficulty falling asleep or staying asleep

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

• swelling of the face, eyes, lips, tongue, arms, or legs

• difficulty breathing or swallowing

• fainting

• rash

• yellowing of the skin or eyes

• fever

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

Do not let anyone else take your medicines.