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Droperidol (Inapsine)

Anesthesia Implications

Updated On: July 10, 2026

Classification:
Butyrophenone; dopamine D2 receptor antagonist
Therapeutic Effects:
Antiemetic, sedation, anxiolysis, antipsychotic
Time to Onset:

IV: 3–10 min
IM: 15-30 min

Time to Peak Effects:

IV: 3-10 min
IM: 30-60 min

Duration:

IV: 2-4 hrs
IM: 3-6 hrs

Primary Considerations:

Potent antiemetic - widely used for PONV prophylaxis and treatment at low doses (0.625–1.25 mg IV); highly effective and cost-efficient.

QTc Prolongation - The FDA issued a black box warning in 2001 regarding QTc prolongation and risk of torsades de pointes — use with caution and perform pre-treatment ECG if risk factors are present. Concurrent use with ondansetron, haloperidol, amiodarone, certain antibiotics (fluoroquinolones, azithromycin), and methadone will have additive QTc prolongation risk.

Sedation & Dysphoria - Produces dose-dependent sedation and will have additive effects with opioids, benzodiazepines, propofol, and volatile agents.

Dysphoria - Patients may appear calm but feel internally anxious ('neuroleptic dysphoria').

Mild hypotension - alpha-1 adrenergic blockade causes peripheral vasodilation; generally well tolerated at antiemetic doses but monitor in hypovolemic patients.

Extrapyramidal symptoms - Rare. Akathisia, acute dystonia, and oculogyric crisis can occur — treat with diphenhydramine 25–50 mg IV or benztropine 1–2 mg IV.

Neuroleptic malignant syndrome - rare but serious; presents with hyperthermia, rigidity, altered consciousness, and autonomic instability — monitor if high doses are used.

OB - crosses the placenta; may cause neonatal CNS and respiratory depression — use with caution in obstetric patients and have resuscitation equipment available. Droperidol is commonly used for intraoperative nausea at low doses (0.625 mg IV); weigh risk vs. benefit given neonatal exposure.

Contraindications:

Absolute - Known hypersensitivity to droperidol or other butyrophenones, QTc >500 ms, known congenital long QT syndrome

Relative - QTc >440 ms (men) / >450 ms (women), hypokalemia, hypomagnesemia, concurrent QT-prolonging drugs, Parkinson's disease, history of torsades de pointes

Caution - Elderly patients, hypovolemia, hepatic impairment, renal impairment, patients on antihypertensives, history of extrapyramidal reactions

IV push dose:

PONV Prophylaxis - 0.625–1.25 mg; doses >1.25 mg offer minimal additional benefit with increased side effects

Adult PONV Treatment - 0.625 mg; may repeat once; max 2.5 mg total in most protocols

Pediatric PONV Treatment - 0.01–0.05 mg/kg IV (max 1.25 mg); limited data — use with caution

Procedural Sedation adjunct - 0.625–2.5 mg

IM dose:

2.5–5.0 mg

Method of Action:

Centrally acting D2 antagonist in the chemoreceptor trigger zone (CTZ) of the area postrema — blocks dopamine-mediated emetic signaling; also modulates mesolimbic pathways producing sedation and anxiolysis. Additionally, alpha-1 adrenergic blockade causes peripheral vasodilation; weak antihistamine and anticholinergic activity.

Metabolism:

Hepatic

Elimination:

Renal (primary), fecal/biliary (secondary)

Reference

Gropper MA, et al. Miller's Anesthesia, 9th ed. Elsevier; 2022.
Flood P, et al. Stoelting's Pharmacology & Physiology in Anesthetic Practice, 5th ed. Wolters Kluwer; 2021.
Gan TJ, et al. Fourth Consensus Guidelines for the Management of Postoperative Nausea and Vomiting. Anesth Analg. 2020;131(2):411–448.
Droperidol [package insert]. International Medication Systems; 2023.
Weibel S, et al. Drugs for preventing postoperative nausea and vomiting in adults after general anaesthesia: a network meta-analysis. Cochrane Database Syst Rev. 2020;10:CD012859.
Gan TJ, Belani KG, Bergese S, et al. Fourth Consensus Guidelines for the Management of Postoperative Nausea and Vomiting. Anesth Analg. 2020;131(2):411-448.link