diltiazem

Diltiazem is a calcium channel blocker. It works by relaxing the muscles of your heart and blood vessels.

Diltiazem is used to treat hypertension (high blood pressure), angina (chest pain), and certain heart rhythm disorders.

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

Important information

You should not use diltiazem if you have very low blood pressure, a serious heart condition such as "sick sinus syndrome" or "AV block" (unless you have a pacemaker), or if you have recently had a heart attack and you have a build-up of fluid in your lungs.

Before taking diltiazem, tell your doctor if you have kidney disease, liver disease, or congestive heart failure.

Diltiazem may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert. Do not stop taking this medication without first talking to your doctor. If you stop taking diltiazem suddenly, your condition may become worse.

Diltiazem may be only part of a complete program of treatment that also includes diet, exercise, and other medications. Follow your diet, medication, and exercise routines very closely.

If you are being treated for high blood pressure, keep using diltiazem even if you feel well. High blood pressure often has no symptoms.

Before taking this medicine

You should not use diltiazem if you are allergic to it, or if you have:

• a serious heart condition such as "sick sinus syndrome" or "AV block" (unless you have a pacemaker);

• very low blood pressure; or

• if you have recently had a heart attack and you have a build-up of fluid in your lungs.

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

• kidney disease;

• liver disease;

• congestive heart failure; or

• if you also take digoxin, or a beta blocker (such as atenolol, carvedilol, metoprolol, propranolol, sotalol, and others).

It is not known whether diltiazem will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Diltiazem can pass into breast milk and may harm a nursing baby. You should not breast-feed while using this medicine.

How should I take diltiazem?

Take diltiazem 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 use this medicine in larger or smaller amounts or for longer than recommended.

Do not crush, chew, break, or open an extended-release diltiazem tablet or capsule. Swallow it whole.

To make swallowing easier, ask your doctor or pharmacist if you can open a diltiazem capsule and sprinkle the medicine into a spoonful of applesauce. Swallow right away without chewing. Do not save the mixture for later use.

Use diltiazem regularly to get the most benefit. Get your prescription refilled before you run out of medicine completely.

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

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

Your blood pressure will need to be checked often. You may also need frequent blood tests.

Store diltiazem at room temperature away from moisture and heat.

What happens if I miss a dose?

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.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of diltiazem can be fatal.

Overdose symptoms may include slow heartbeat, weakness, chest pain, shortness of breath, or fainting.

What should I avoid while taking diltiazem?

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

Diltiazem may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Avoid drinking alcohol while taking diltiazem.

Avoid taking herbal supplements containing St. John"s wort at the same time you are taking diltiazem.

Diltiazem side effects

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

Call your doctor at once if you have:

• slow heartbeats;

• pounding heartbeats or fluttering in your chest;

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

• heart problems - shortness of breath (even with mild exertion), swelling, rapid weight gain;

• liver problems - nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or

• severe skin reaction - fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Common diltiazem side effects may include:

• dizziness, weakness;

• headache;

• nausea; or

• rash.

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.

See also: Side effects (in more detail)

Diltiazem dosing information

Usual Adult Dose for Hypertension:

Initial dose: 30 to 60 mg orally 3 to 4 times a day.
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day.
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
XR maintenance dose: 240 to 480 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 420 mg orally once a day.

IV Dosing:
Initial bolus doses: 0.25 mg/kg as a bolus administered over 2 minutes. A second bolus of 0.35 mg/kg may be used if necessary.
Initial infusion dose: 5 mg/hr.
Maintenance infusion dose: The infusion rate may be increased in 5 mg/hr increments up to 15 mg/hr.

Usual Adult Dose for Atrial Fibrillation:

Initial dose (oral): 30 to 60 mg orally 3 to 4 times a day
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 420 mg orally once a day.

Initial dose (IV): 0.25 mg/kg actual body weight bolus over 2 minutes. If necessary, a second bolus of 0.35 mg/kg ABW may be given. In some cases, an infusion of diltiazem 5 mg/hour may be started, and advanced in 5 mg/hour increments to 15 mg/hour for up to 24 hours.

Usual Adult Dose for Atrial Flutter:

Initial dose (oral): 30 to 60 mg orally 3 to 4 times a day
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 420 mg orally once a day.

Initial dose (IV): 0.25 mg/kg actual body weight bolus over 2 minutes. If necessary, a second bolus of 0.35 mg/kg ABW may be given. In some cases, an infusion of diltiazem 5 mg/hour may be started, and advanced in 5 mg/hour increments to 15 mg/hour for up to 24 hours.

Usual Adult Dose for Supraventricular Tachycardia:

Initial dose (oral): 30 to 60 mg orally 3 to 4 times a day
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 420 mg orally once a day.

Initial dose (IV): 0.25 mg/kg actual body weight bolus over 2 minutes. If necessary, a second bolus of 0.35 mg/kg ABW may be given. In some cases, an infusion of diltiazem 5 mg/hour may be started, and advanced in 5 mg/hour increments to 15 mg/hour for up to 24 hours.

Usual Adult Dose for Angina Pectoris Prophylaxis:

Initial dose: 30 to 60 mg orally 3 to 4 times a day
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 360 mg orally once a day.

Usual Adult Dose for Congestive Heart Failure:

Initial dose: 30 to 60 mg orally 3 to 4 times a day
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 360 mg orally once a day.

What other drugs will affect diltiazem?

Many drugs can interact with diltiazem, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.