Products
Diltiazem is commercially available in tablet and capsule form (Dilzem, generic). It has been approved in many countries since 1982.
Structure and properties
Diltiazem (C22H26N2O4S, Mr = 414.52 g/mol) is a benzothiazepine derivative. It is present in drugs as diltiazem hydrochloride, a white crystalline powder with a bitter taste that is readily soluble in water.
Effects
Diltiazem (ATC C08DB01) has vasodilator, antihypertensive, antianginal, and negative chronotropic properties. The effects are due to inhibition of calcium influx at the heart and in vascular smooth muscle. This results in the following effects:
- Diltiazem decreases the oxygen demand of the heart muscle.
- It reduces peripheral resistance.
- It reduces the afterload of the heart.
- It improves blood flow to the heart.
Diltiazem undergoes marked first-pass metabolism and therefore has a deep oral bioavailability of only 40%. It has a half-life of approximately 6 hours.
Indications
- For the treatment of coronary artery disease: seizure prophylaxis in chronic coronary insufficiency or angina, vasospastic angina, and angina in post-myocardial infarction state.
- For the treatment of hypertension.
- As an ointment: for the treatment of anal fissures (not registered in many countries) see under diltiazem ointment.
Dosage
According to the professional information. The non-retarded preparations are administered up to three times daily. The sustained-release medications need to be taken only once or twice daily.
Contraindications
- Hypersensitivity
- Cardiogenic shock
- Complicated, fresh myocardial infarction
- Decompensated heart failure
- Sinus node syndrome
- Conduction disorders
- Bradycardia
- Pregnancy and lactation
Full precautions can be found in the drug label.
Interactions
Diltiazem is a substrate of CYP3A4 and corresponding drug-drug interactions are possible. Combination with antihypertensive agents may result in increased blood pressure lowering.
Adverse effects
The most common possible adverse effects include slow heartbeat (bradycardia), conduction abnormalities, allergic reactions, rash, poor appetite, edema, flushing, dizziness, headache, fatigue, weakness, and nausea. The side effects are due in part to vasodilatation.
