Diltiazem Hydrochloride

Generic Details

Generic Name

Diltiazem Hydrochloride

Other Names

  • Cardizem
  • Diltiazem HCL
  • Taztia
  • Tiazac

Drug Class

  • Calcium Channel Blocker
  • Antiarrhythmic

Chemical Formula

C22H26N2O4S

Molecular Weight

414.52 g/mol

Mechanism of Action

  • Inhibits calcium ion influx through L-type calcium channels in cardiac and smooth muscle cells, leading to vasodilation and decreased cardiac workload.

Indications

  • Hypertension
  • Angina pectoris
  • Atrial fibrillation/flutter
  • Supraventricular tachyarrhythmias

Common Dosage Forms

  • Tablet
  • Capsule
  • Extended-release capsule

Typical Dosage

  • 120-480 mg/day in divided doses for hypertension
  • 180-360 mg/day in divided doses for angina

Pediatric Dosage

  • Safety and efficacy not established in children

Geriatric Dosage

  • May require lower initial doses due to age-related reductions in hepatic and renal function

Side Effects

  • Dizziness
  • Headache
  • Edema
  • Constipation
  • Bradycardia
  • Hypotension
  • Flushing

Contraindications

  • Sick sinus syndrome
  • 2nd or 3rd-degree AV block
  • Hypotension
  • Severe heart failure

Pregnancy Category

  • Category C - Safety in pregnancy has not been established, potential benefits may warrant its use

Lactation Safety

  • Limited data available, caution advised

Drug Interactions

  • Simvastatin
  • Beta-blockers
  • Cyclosporine
  • Digoxin

Overdose Symptoms

  • Hypotension
  • Bradycardia
  • Cardiac conduction disturbances

Antidote for Overdose

  • Calcium chloride or calcium gluconate for severe hypotension or cardiac conduction abnormalities

Storage Conditions

  • Store at room temperature away from moisture and heat

Pharmacokinetics

  • Absorption: Rapidly absorbed after oral administration
  • Distribution: Highly protein-bound, distributed extensively into tissues
  • Metabolism: Extensively metabolized in the liver via CYP3A4
  • Excretion: Excreted mainly in the urine as metabolites

Precautions

  • Monitor blood pressure and heart rate regularly
  • Avoid abrupt withdrawal to prevent rebound hypertension or angina

Warnings

  • Do not crush or chew extended-release formulations
  • Avoid grapefruit juice due to CYP3A4 interactions

Others

  • May be used off-label for Raynaud's phenomenon