Diltiazem: uses, side effects & brands

Written & medically reviewed by Dr. Sanjay Anbu, MBBS · Last reviewed 5 November 2026

Diltiazem is a calcium-channel blocker for angina and some heart rhythms. It belongs to the Calcium-channel blocker (blood pressure) group. These relax and widen blood vessels to lower blood pressure and ease angina.

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Drug type — dosing is set by your doctor

Measure	Range
Drug class	Calcium-channel blocker (blood pressure)
Type	Prescription
Dose	Individual — ask your doctor or pharmacist

What it is used for

Angina (chest pain)
High blood pressure
Slowing a fast heart rate in atrial fibrillation

Common brand names

India: Dilzem, Angizem
Worldwide: Cardizem, Tiazac

Common side effects

Headache or flushing
Ankle swelling
Slow pulse or dizziness
Constipation or upset stomach

Before taking it — precautions

Tell your doctor about heart failure or heart-rhythm problems
Many medicines interact (some statins, blood thinners, beta-blockers) — share your full medicine list
Swallow long-acting forms whole and do not switch brands without advice

When to see a doctor urgently

Very slow pulse, fainting or severe dizziness (urgent)
Breathlessness or new swelling of the legs
Severe skin rash or blistering (rare — urgent)

Not a prescription — no dose shown. The right dose of diltiazem depends on age, weight, kidney/liver function and the condition, so MedDroid does not show a dose here. Always get your dose from a doctor or pharmacist and the leaflet inside the pack. General educational information only.

Frequently asked questions

How is diltiazem different from amlodipine?

Diltiazem also slows the heart rate, so it is used for some heart-rhythm problems, while amlodipine mainly relaxes blood vessels.

Can I take diltiazem with a beta-blocker?

Only under close medical supervision, because together they can slow the heart too much.

Does diltiazem interact with cholesterol medicines?

Yes — it can raise levels of some statins, such as simvastatin, so your doctor may adjust them.

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Sources & further reading

Reviewed by Dr. Sanjay Anbu, MBBS. MedDroid is an AI medical assistant and can make mistakes. It provides general health information, not a diagnosis or medical advice — always consult a qualified clinician. In an emergency, contact your local emergency number immediately.