Can droperidol cause bradycardia?

Droperidol and Bradycardia

Droperidol should be avoided in patients with bradycardia as it carries an FDA black box warning for QT prolongation and potentially fatal cardiac arrhythmias, with bradycardia specifically listed as a risk factor for these complications. 1

Cardiac Effects of Droperidol

• Droperidol carries an FDA black box warning due to its potential to cause QT prolongation, torsades de pointes, and sudden cardiac death 1
• The FDA explicitly warns that droperidol should be administered with "extreme caution" in the presence of clinically significant bradycardia (less than 50 bpm) 1
• Droperidol is contraindicated in patients with a prolonged QTc interval (>440 ms in males, >450 ms in females) and should be avoided in patients with risk factors for QT prolongation, including bradycardia 2

Mechanism and Risk Factors

• Droperidol, like other antipsychotics, causes QTc prolongation through a quinidine-like effect on cardiac conduction 2
• A dose-dependent prolongation of the QT interval has been observed within 10 minutes of droperidol administration 1
• Pre-existing bradycardia significantly increases the risk of developing dangerous arrhythmias when droperidol is administered 3
• Other risk factors that compound the risk when bradycardia is present include:
  • Concomitant treatment with other QT-prolonging medications 1
  • Electrolyte imbalances, particularly hypokalemia and hypomagnesemia 1
  • Age ≥65 years 2
  • History of congestive heart failure 2

Clinical Evidence

• A study of 55 patients receiving droperidol (0.25 mg/kg IV) showed significant QT prolongation in 70% of cases by the end of the first minute after administration 4
• Case reports have documented ventricular tachycardia occurring after even low prophylactic doses (1.25 mg) of droperidol in patients with mild QT interval prolongation 5
• While some studies suggest the risk may be overstated (a review of 16,546 patients found only one case of torsades de pointes, an incidence of 0.006%), caution is still warranted, especially in patients with bradycardia 6

Recommendations for Clinical Practice

• All patients should undergo a 12-lead ECG prior to administration of droperidol to determine if a prolonged QT interval is present 1
• If bradycardia is present (HR <50 bpm), droperidol should be avoided and alternative medications should be considered 1
• If droperidol must be used despite risk factors (when benefits outweigh risks), ECG monitoring should be performed prior to treatment and continued for 2-3 hours after completing treatment 1
• Fluids and other countermeasures to manage hypotension should be readily available when administering droperidol 1

Alternative Medications

• For sedation: Benzodiazepines are recommended as first-line alternatives due to their favorable safety profile 7
• For antiemesis: 5-HT3 antagonists (ondansetron, granisetron), metoclopramide, or prochlorperazine are safer alternatives 3
• For agitation: Atypical antipsychotics like ziprasidone (20 mg IM) have shown efficacy with fewer cardiovascular side effects 7

Conclusion

Droperidol has a clear association with bradycardia and should be avoided in patients who already have bradycardia or are at risk for developing it. The FDA black box warning specifically identifies bradycardia as a risk factor for QT prolongation and potentially fatal arrhythmias when using droperidol. Alternative medications should be strongly considered in patients with bradycardia.