Title: Droperidol
CAS Registry Number: 548-73-2
CAS Name: 1-[1-[4-(4-Fluorophenyl)-4-oxobutyl]-1,2,3,6-tetrahydro-4-pyridinyl]-1,3-dihydro-2H-benzimidazol-2-one
Additional Names: 1-[1-[3-(p-fluorobenzoyl)propyl]-1,2,3,6-tetrahydro-4-pyridyl]-2-benzimidazolinone; 1-[1-[4-(p-fluorophenyl)-4-oxobutyl]-1,2,3,6-tetrahydro-4-pyridyl]-2-benzimidazolinone
Manufacturers' Codes: R-4749
Trademarks: Dehydrobenzperidol (Janssen); Dridol; Droleptan (Le Brun); Inapsine (McNeil)
Molecular Formula: C22H22FN3O2
Molecular Weight: 379.43
Percent Composition: C 69.64%, H 5.84%, F 5.01%, N 11.07%, O 8.43%
Literature References: Prepn: P. A. J. Janssen, J. F. Gardocki, US 3161645 (1964 to Janssen). Pharmacology and toxicity: J. Yelnosky et al., Toxicol. Appl. Pharmacol. 6, 37 (1964). Comprehensive description: C. A. Janicki, R. K. Gilpin, Anal. Profiles Drug Subs. 7, 171-192 (1978).
Derivative Type: Hydrate
Properties: Crystals, mp 145-146.5°. uv max (9:1, 0.1M HCl:methanol): 245, 280 nm (e 15600, 7500). Soly at 25° (g/100 ml): chloroform 40; DMF 17; benzene 0.55; methanol 0.41; ethanol 0.34; ether 0.24; 0.1M HCl 0.15; water <0.001. pKa 7.64. Heat and light sensitive. LD50 in mice (mg/kg): 125 s.c.; 43 i.v. (Yelnosky).
Melting point: mp 145-146.5°
pKa: pKa 7.64
Absorption maximum: uv max (9:1, 0.1M HCl:methanol): 245, 280 nm (e 15600, 7500)
Toxicity data: LD50 in mice (mg/kg): 125 s.c.; 43 i.v. (Yelnosky)
NOTE: Ingredient of Thalamonal, Innovar.
Therap-Cat: Antipsychotic.
Therap-Cat-Vet: Tranquilizer.
Keywords: Antipsychotic; Butyrophenones.
Droprenilamine Dropropizine Drosera Drosophilin A Drotaverine

Skeletal formula of droperidol
Space-filling model of droperidol
Systematic (IUPAC) name
Clinical data
Pregnancy cat. C (US)
Legal status -only (US)
Routes Intravenous, Intramuscular
Pharmacokinetic data
Metabolism Hepatic
Half-life 2.3 hours
CAS number 548-73-2
ATC code N05AD08
PubChem CID 3168
DrugBank DB00450
KEGG D00308
Chemical data
Formula C22H22FN3O2 
Mol. mass 379.428 g/mol

Droperidol /droʊˈpɛrIdɔːl/ (Inapsine, Droleptan, Dridol, Xomolix, Innovar [combination with fentanyl]) is an antidopaminergic drug used as an antiemetic and antipsychotic. Droperidol is also often used for neuroleptanalgesic anesthesia and sedation in intensive-care treatment.