Diltiazem

ATC code

C08DB01

Therapeutic class

Non-dihydropyridine calcium channel blocker · Benzothiazepine derivative

Forms

oral tablet, extended-release oral capsule, extended-release oral tablet

Brand names

Diltiazem Hydrochloride (US) · Cardizem (US) · Tiazac (US) · Diltiazem Sandoz (ES) · Bi Tildiem (FR)

Overall confidence

high

Regulatory sources consulted

openfda-label-90a6eaea-ad5f-4d7a-8159-6c8f4b2562dd
aemps-ft-62328
ansm-rcp-68227652
Clinical Pharmacology Knowledge
OpenFDA · C08DB01
RxNorm rxcui 3443 ↗

Approved indications

Treatment of hypertension. It may be used alone or in combination with other antihypertensive medications.
Management of chronic stable angina and angina due to coronary artery spasm.

Contraindications

Absolute

Sick sinus syndrome (except in the presence of a functioning ventricular pacemaker).
Second- or third-degree AV block (except in the presence of a functioning ventricular pacemaker).
Severe hypotension (systolic < 90 mm Hg).
Acute myocardial infarction with pulmonary congestion.
Severe bradycardia (≤ 40 bpm).
Left ventricular failure with pulmonary stasis.

Clinical warnings

Major warning · Cardiac Conduction: May lead to excessive bradycardia or AV block, especially when combined with beta-blockers or digitalis. — FDA
Major warning · Congestive Heart Failure: Use with caution in patients with impaired ventricular function due to its negative inotropic effect. — FDA
Acute Hepatic Injury: Elevations of transaminases have been observed. In rare instances, significant hepatic injury has occurred. — FDA

Drug interactions

HighBeta-blockersC07
Mechanism: Additive effects on cardiac contractility, automaticity, and conduction (negative inotropic, chronotropic, and dromotropic effects).
Recommendation: Association not recommended or requires close clinical and ECG monitoring, especially in the elderly or at the start of treatment. Increased risk of depression.
FDA labelANSM RCP
HighIvabradineC01EB17
Mechanism: Additional risk of heart rate reduction due to the additive effect of diltiazem with ivabradine.
Recommendation: Combination is contraindicated.
ANSM RCP
HighSimvastatinC10AA01
Mechanism: Diltiazem is a moderate CYP3A4 inhibitor, which significantly increases exposure to statins metabolized by this pathway (e.g., simvastatin, lovastatin), increasing the risk of myopathy and rhabdomyolysis.
Recommendation: Limit simvastatin dose to 10 mg/day or lovastatin to 20 mg/day when co-administered with diltiazem. Consider statins not metabolized by CYP3A4 (pravastatin, rosuvastatin).
FDA labelClinical Pharmacology Knowledge
ModerateDigoxinC01AA05
Mechanism: Additive effects in prolonging AV conduction. Diltiazem may also increase digoxin concentrations (P-gp inhibition).
Recommendation: Clinical and ECG monitoring. Consider monitoring digoxin levels when starting or adjusting diltiazem therapy.
FDA label

Adverse events

Common (≥1%)

lower limb edema · headache · dizziness · asthenia · AV block · flushing · nausea · constipation

Rare but serious

Stevens-Johnson syndrome · toxic epidermal necrolysis · congestive heart failure · sinoatrial block · asystole · hepatotoxicity · acute generalized exanthematous pustulosis

Pregnancy and lactation

There are no well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus. Generally not recommended during pregnancy.