Diltiazem

Administration

• Type: Calcium channel blocker
• Dosage Forms
  • IV: 25 mg/5 mL and 50 mg/10 mL bottles
  • Oral: 30 mg, 60 mg, 90 mg
• Routes of Administration: IV, PO
• Common Trade Names: Cardizem

Indications

• Atrial fibrillation with rapid ventricular response (if hemodynamically stable)
• Supraventricular tachycardia (if hemodynamically stable)

Adult Dosing

• Loading dose = 0.25 mg/kg (max=20 mg) IV bolus over 2 minutes
  • Can consider breaking down into 10 mg boluses in older patients to decrease risk of adverse reactions
  • If ineffective after 15 minutes: 0.35mg/kg (max=25mg) over 2 minutes
  • If effective: Start infusion at 5-15 mg/hr
    • Consider 30mg IR PO or home dose to avoid need for a drip

Pediatric Dosing

• Contraindicated in pediatric patients <1yo
• See critical care quick reference for drug doses by weight

Special Populations

• Pregnancy Rating: C
• Lactation: Does appear to diffuse into breast milk, but doses are typically not harmful to infants
• Renal Dosing: Not studied, use caution
• Hepatic Dosing: Not studied, use caution

Contraindications

• Allergy to drug/class
• Infants <1yo
• Wide-complex tachycardia due to bypass tract (e.g. WPW)
• Symptomatic severe hypotension
• Sick sinus syndrome/2nd or 3rd degree heart block if no pacemaker
• PO: acute MI and pulmonary congestion
• Ventricular tachycardia
• Caution if:
  • Hypertrophic cardiomyopathy
  • LV dysfunction
  • Concomitant beta-blockade
  • Hepatic/renal impairment
  • Heart failure

Adverse Reactions

Serious

• Bradycardia, AV block, BBB
• Hypotension
• CHF
• SJS/TEN

Common

• Peripheral edema
• Elevated LFTs
• Headache
• Dizziness
• Nausea/vomiting, diarrhea, contipation
• Flushing, vasodilation
• Gingival hyperplagia
• Myalgia
• Bronchitis, sinus congestion, dypsnea
• Hemolytic anemia, thrombocytopenia
• Extrapyramidal symptoms

Pharmacology

• Onset of action = 2-3min (IV)
• Duration of action = 1-3hr (IV)
• Half life: 3-5h
• Metabolism: Hepatic
• Excretion: Urine/feces

Mechanism of Action

• Class IV - Inhibits Ca influx
  • Slows AV nodal conduction

See Also

• Antiarrhythmics
• Calcium Channel Blocker Toxicity
• Atrial Fibrillation with RVR