Generic name: Diltiazem hydrochloride.

Other brand names: Cardizem CD, Cardizem SR, Dilacor XR.

Cardizem is a calcium channel blocker. It increases the amount of oxygen that reaches the heart muscle.  

Quick Facts About Cardizem


Used to treat chest pain (angina) due to coronary artery spasm and chronic stable angina. Also used to treat high blood pressure, loss of circulation in the fingers and toes (Raynaud’s Syndrome), involuntary movements (tardive dyskinesia), and to prevent second heart attack.

Cardizem Dosage

Take before meals and at bedtime; must swallow whole.

  • Usual adult dose: 180 to 360 milligrams divided into 3 or 4 smaller doses. For Cardizem SR (sustained release) — 60 to 120 milligrams 2 times per day, up to 240 to 360 milligrams per day. For Cardizem CD (once-a-day form) — hypertension dose is 180 to 240 milligrams per day; angina dose is 120 to 180 milligrams per day.
  • Usual child dose: not generally prescribed for children.
  • Missed dose: take as soon as possible, unless almost time for next dose. In that case, do not take missed dose; go back to regular schedule. Do not double doses.

Cardizem Side Effects

Overdose symptoms:

feinting, dizziness, and irregular pulse due to heart block, heart failure, low blood pressure, very slow heartbeat. If you suspect an overdose, immediately seek medical attention.

More common side effects: abnormally slow heartbeat (Cardizem SR and CD), dizziness, fluid retention, flushing (Cardizem SR and CD), headache, nausea, rash, weakness.

Less common Cardizem side effects: abnormal dreams, amnesia, anemia, blood disorders, congestive heart failure, constipation, depression, diarrhea, difficulty sleeping, drowsiness, dry mouth, excessive urination at night, eye irritation, feinting, hair loss, hallucinations, heart attack, high blood sugar, hives, impotence, increased output of pale urine, indigestion, insomnia, irregular heartbeat, itching, joint pain, labored breathing, loss of appetite, low blood pressure, low blood sugar, muscle cramps, nasal congestion, nervousness, nosebleed, palpitations, personality change, rapid heartbeat, reddish or purplish spots on skin, ringing in ears, sexual difficulties, skin peeling, sensitivity to light, severe chest pain, sleepiness, taste alteration, thirst, tingling or pins and needles, tremor, unusual gait, vision changes, vomiting, weight increase, welts.


Inform your doctor before combining Cardizem with:

Inform your doctor before combining Cardizem with: beta-blockers such as Tenormin and Inderal, Cimetidine (Tagamet), Cyclosporine (Sandimmune), Digoxin (Lanoxin), Ranitidine (Zantac).

INo known food/other substance interactions.

Special Cautions

If pregnant or planning to become pregnant, inform your doctor immediately. Appears in breast milk; could affect a nursing baby.

No special precautions apply to seniors.

Not generally prescribed for children.

  • Do not take if you have low blood pressure or allergy to Cardizem.
  • Should not take Cardizem without a ventricular pacemaker if you have “sick sinus” syndrome or 2nd or 3rd degree heart block (irregular heartbeat).
  • Use with caution if you have: congestive heart failure, kidney or liver disease.
  • Monitor pulse rate, may cause heart rate to become too slow.

Note: provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Cardizem side effects, please contact your healthcare provider.