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

Adult Dosing

Atrial fibrillation with rapid ventricular response (if hemodynamically stable)

• 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

Supraventricular tachycardia (if hemodynamically stable)

• Same as for atrial fibrillation with rapid ventricular response (see above)

Pediatric Dosing

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

Special Populations

Pregnancy Rating

• Pregnancy Rating: C

Lactation risk

• Lactation: Does appear to diffuse into breast milk, but doses are typically not harmful to infants

Renal Dosing

• Adult: Not studied, use caution
• Pediatric: Not studied, use caution

Hepatic Dosing

• Adult: Not studied, use caution
• Pediatric: 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

Indications by Condition

The following table is automatically generated from disease/condition pages across WikEM.

Indication	Dose	Context	Route	Population
Atrial fibrillation (main)	0.25-0.35 mg/kg IV (typical 20 mg), then 25 mg IV if needed; followed by 60-120 mg PO or drip	Rate control (1st line CCB)	IV/PO	Adult
Atrial fibrillation with RVR	0.25mg/kg (max 20mg) IV over 2min; repeat 0.35mg/kg after 15min; drip 5-20mg/hr	First-line rate control (CCB)	IV	Adult
Atrial flutter	2.5 mg/min until HR <100 (max 50 mg)	Rate control	IV	Adult
Nontraumatic thoracic aortic dissection	0.25mg/kg load over 2-5min, then 5mg/hr infusion	Heart rate control if beta-blocker contraindicated	IV	Adult
Paroxysmal supraventricular tachycardia	0.25 mg/kg IV over 2 min; may repeat 0.35 mg/kg after 15 min; then infusion 5-20 mg/hr	Calcium-channel blocker (2nd line)	IV/IV drip	Adult

See Also

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