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
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