Diltiazem – Information, Uses, Side effects and Dosage


Drug trade name: Cardizem

Category: Calcium channel blocker

Generic Name: diltiazem

Introduction and Quick Information:


Diltiazem is a calcium channel blockers. Diltiazem is prescribed to treat chest pain (angina), abnormal heart rhythms, high blood pressure (hypertension). Diltiazem works by relaxing blood vessels. 

Is Diltiazem U.S. FDA Approved?

Diltiazem is U.S. FDA approved only on prescription in a various dosage form such as extended-release capsule, extended release coated capsule, extended-release tablets, immediate release tablets and bolus injections.

Usage and Benefits of Diltiazem:

Diltiazem is a prescription medicine generally used to treat certain chest pain (angina) and hypertension (high blood pressure). By controlling blood pressure (lowers systolic and diastolic blood pressure), diltiazem can reduce the risk of several other health problems such as congestive heart failure, stroke, and heart disease.

Chest pain is medically known as angina. Chest pain can be stable, unstable or variant. Diltiazem is prescribed to treat all types of chest pain but its dosages can differ depending on the severity of angina.

Diltiazem is a nondihydropyridine calcium channel blocker that decreases uneven heart rate. For this reason, Diltiazem is considered as a useful medicine for treating certain types of arrhythmias (irregular heart rhythms).

Note: Diltiazem is not approved for children due to safety concerns. For further information, ask your child’s healthcare provider about the risks and benefits of Diltiazem.

Diltiazem Side Effects:

Here are some common side effects of diltiazem:

  • Swelling or water retention in lower legs, feet, and hands
  • Headaches
  • Indigestion
  • Infections
  • A sore throat
  • Nausea
  • Sinus congestion
  • Slow heart rate
  • Fatigue, lightheadedness, dizziness or fainting
  • Coughing
  • Hallucinations
  • Chest pain (angina)
  • High blood sugar
  • Allergic symptoms: Wheezing, hives, rash, difficulty breathing, swallowing, and swelling.
  •  Skin rash (blister form)

General Recommended Dosages of Diltiazem:

Take diltiazem as prescribed by your doctor. Tell your doctor or pharmacist if you have trouble swallowing (capsule form) diltiazem as a whole. Do not stop taking Diltiazem without informing your healthcare provider.


If you are taking diltiazem for high blood pressure, keep taking this medicine even if your condition is controlled. High blood pressure generally has no evident symptoms hence your doctor might prescribe this medicine for the rest of your life.

In Case I Take Overdose?

Overdose consequences might vary as diltiazem is prescribed to treat more than one health condition. Overdose symptoms may include shortness of breath, fainting or feeling light-headed, chest pain, weakness, slow heartbeat etc. If you find these symptoms, seek medical help.

In Case I Miss my Dose?

In case the dose is missed, take it as soon as you recall. If, it the time for the next dose then skip the missed dose.

Drug Interactions of Diltiazem:

There are some drugs which can potentially interact with diltiazem such as:

  • carbamazepine (Carbatrol)
  • cyclosporine (Gengraf)
  • digoxin (Lanoxin)
  • quinidine (Quin-G)
  • buspirone (BuSpar)
  • amiodarone (Cordarone)
  • cimetidine (Tagamet)
  • rifampin (Rifadin)
  • A beta-blocker such as carvedilol, atenolol, labetalol, nadolol, sotalol, propranolol, metoprolol,
  • HIV/AIDS medicine such as delavirdine, pravastatin, rosuvastatin, fosamprenavir, atazanavir, nelfinavir, ritonavir
  • An antibiotic such as telithromycin, clarithromycin, erythromycin, dalfopristin/quinupristin
  • Cholesterol medications such as simvastatin, lovastatin, atorvastatin,
  • Antifungal medication such as ketoconazole, miconazole, voriconazole, itraconazole
  • A sedative such as triazolam, midazolam.

Life Style and Food Habits You Must Follow When on Diltiazem:

Since this medicine is prescribed to treat chest pain and hypertension and other health condition hence you may need to follow some strict diet and exercise routine while taking this medicine. With this drug, alcohol intake should be minimized or discontinued.

How Safe Is Diltiazem for Pregnant Women or Nursing Mothers?

Pregnancy category: C (Use with caution if benefits outweigh risks)

Lactation: Drug enters breast milk; because of risk for serious adverse reactions in nursing infants from diltiazem, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Complications and Conditions Possible Due to Prolonged Use of Diltiazem:

Prolonged use of any medicine can have harmful effects on the body. However, in some cases, your doctor might prescribe this medicine for longer than recommended periods.

Note: People who are addicted to drugs or drug abused should strictly avoid taking diltiazem without consulting your doctor.

Availability of Diltiazem:

This drug is available only by prescription.