MedicinePOMEssential

Diltiazem

Calcium channel blocker for high blood pressure, angina and some other conditions.

Clinical information

Common uses

high blood pressure
preventing angina chest pain
reducing Raynaud's phenomenon attacks
healing anal fissures (as cream or ointment)

Common side effects

swollen hands, ankles or feet
headaches
feeling dizzy or light-headed
flushing
constipation

Cautions

do not stop suddenly — blood pressure may rise
can cause dizziness — do not drive until you feel OK
may not suit heart failure, heartbeat, liver or kidney problems
keep to the same brand once started

Interactions

antibiotics such as clarithromycin, erythromycin or rifampicin
antifungals such as itraconazole or ketoconazole
epilepsy medicines such as carbamazepine or phenytoin
ciclosporin or tacrolimus (immunosuppressants)
simvastatin above 20mg a day
St John's wort (herbal remedy)

Pregnancy: not usually recommended — talk to your doctor

Reference information, not medical advice — always follow your doctor or pharmacist. Source: NHS Medicines A–Z, nhs.uk/medicines/diltiazem (accessed 2026-08-16)

Approved brands & formulations5

Brand name	Dosage form	Strength	Importer	Category
Diltiazem	Topical Preparations ( Ointment )	0.02	—	POM
Diltiazem	Tablet	120 mg	—	POM
Diltiazem	Tablet	90mg	—	POM
Diltiazem	Parenteral ( Injection )	25mg/5ml	MFDA designated importers with Pre Authorization approval before import	hospital
Diltiazem Hcl	Parenteral ( Injection )	5 mg/ml	MFDA designated importers with Pre Authorization approval before import	hospital