DROPERIDOL

Description

D roperidol is a butyrophenone that has potent antidopaminergic (D2) activity and mild α2-blocking actions. It produces sedation and anxiolysis and is an effective antiemetic. A dverse effects include vasodilatation and hypotension, and at higher doses, dystonic reactions can occur. D roperidol was used for premedication and in neuroleptanaesthesia until reports of death from long QT syndrome led to its withdrawal in 2001. It has recently been reintroduced and licenced at lower doses for prevention of postoperative nausea and vomiting. D roperidol has an onset of 3–10 min after i.v. injection and duration of action of 6–12h. It undergoes hepatic metabolism, but approximately 10% of the drug is excreted unchanged in the urine.

Chemical Properties

Pale Yellow Solid

Originator

Dehydrobenzperidol,Janssen,W. Germany,1963

Uses

A D1DR and D2DR inhibitor.

Uses

H2 antihistamine

Uses

A D1, D2 dopamine receptor antagonist; butyrophenone antipsychotic and anti-emetic.

Uses

The neuroleptic droperidol possesses antipsychotic, sedative, and antishock action. It potentiates the action of drugs for narcosis. In psychiatric practice, droperidol is used for psychomotor excitement and hallucinations. The principal use of this drug lies in anesthesiology for neuroleptanalgesia in combination with fentanyl. It is used in premedication as well as in surgical operations and post-operational circumstances.

Definition

ChEBI: An organofluorine compound that is haloperidol in which the hydroxy group has been eliminated with the introduction of a double bond in the piperidine ring, and the 4-chlorophenyl group has been replaced by a benzimidazol-2-on-1-yl group. It is used in the management of chemotherapy-induced nausea and vomiting, and in conjunction with an opioid analgesic such as fentanyl to maintain the patient in a calm state of neuroleptanalgesia with indifference to surroundings but still able to cooperate with the surgeo .

Manufacturing Process

A mixture of 10 parts of γ-chloro-4-fluorobutyrophenone, 5.5 parts of 1- (1,2,3,6-tetrahydro-4-pyridyl)-2-benzimidazolinone, 4 parts of sodium carbonate, and 0.1 part of potassium iodide in 176 parts of 4-methyl-2- pentanone is stirred and refluxed for 64 hours. The cooled reaction mixture is filtered and the solvent is evaporated from the filtrate to leave an oily residue which is dissolved in toluene. The toluene solution is filtered and the solvent is evaporated. The resultant residue is recrystallized from a mixture of 32 parts of ethyl acetate and 32 parts of diisopropyl ether to give 1-[1-[(4-fluorobenzoyl)propyl]-1,2,3,6-tetrahydro-4-pyridyl]-2-benzimidazolinone hydrate melting at about 145°-146.5°C.

brand name

Inapsine (Akorn);Dehydrobenzperidol;Diaperidol;Inopsin.

Therapeutic Function

Tranquilizer

General Description

Droperidol, 1-1-[3-(p-fluorobenzoyl)propyl]-1,2,[3,6-tetrahydro-4-pyridyl]-2-benzimidazolinone(Inapsine). Centrally acting acetylcholinesteraseinhibitors may increase the risk of antipsychotic-relatedEPS. CNS depressants may produce additive sedativeeffects (benzodiazepines, barbiturates, antipsychotics,ethanol, opiates, and other sedative medications).Droperidol in combination with certain forms of inhalationanesthetics may produce peripheral vasodilatation and hypotension.Metoclopramide may increase the risk of EPSproduced by droperidol.

General Description

Droperidol, 1-{1-[3-(p-fluorobenzoyl)propyl]-1,2, 3,6-tetrahydro-4-pyridyl}-2-benzimidazolinone(Inapsine), may be used alone as a preanestheticneuroleptic or as an antiemetic. Because of its very shortactingand highly sedating properties, its most frequent useis in combination (Innovar) with the narcotic agent fentanyl(Sublimaze) preanesthetically.

Biochem/physiol Actions

D1, D2 dopamine receptor antagonist; butyrophenone antipsychotic and anti-emetic.

Synthesis

Droperidol, 1-[1-[3-(p-fluorobenzoyl)propyl]-1,2,3,6,4-piridyl]-2-benzymidazolinone (6.3.11), is synthesized from 1-benzyl-3-carbethoxypiperidin-4-one (3.1.47), which is reacted with o-phenylendiamine. Evidently, the first derivative that is formed under the reaction conditions, 1,5-benzdiazepine, rearranges into 1-(1-benzyl-1,2,3,6- tetrahydro-4-piridyl)-2-benzymidazolone (6.3.9). Debenzylation of the resulting product with hydrogen over a palladium catalyst into 1-(1,2,3,6-tetrahydro-4-piridyl)-2-benzimidazolon (6.3.10) and subsequent alkylation of this using 4??-chloro-4-fluorobutyrophenone (6.3.4) yields droperidol (6.3.11) [47¨C49].

Drug interactions

Potentially hazardous interactions with other drugs
Anaesthetics: enhanced hypotensive effect; effects of thiopental enhanced.
Analgesics: increased risk of ventricular arrhythmias with methadone; increased risk of convulsions with tramadol; enhanced hypotensive and sedative effects with opioids.
Anti-arrhythmics increased risk of ventricular arrhythmias with anti-arrhythmics that prolong the QT interval, e.g. procainamide, disopyramide, dronedarone and amiodarone - avoid.
Antibacterials: increased risk of ventricular arrhythmias with moxifloxacin and macrolides - avoid; increased risk of ventricular arrhythmias with delamanid.
Antidepressants: increased risk of ventricular arrhythmias with fluoxetine, fluvoxamine, sertraline or tricyclics - avoid; possible increased risk of convulsions with vortioxetine.
Antiepileptics: convulsive threshold lowered.
Antimalarials: avoid with artemether/lumefantrine and piperaquine with artenimol; increased risk of ventricular arrhythmias with chloroquine, hydroxychloroquine or quinine - avoid.
Antipsychotics: increased risk of ventricular arrhythmias with amisulpride, pimozide, sulpiride, phenothiazines that prolong QT interval or haloperidol - avoid; possibly increased risk of ventricular arrhythmias with risperidone.
Antivirals: concentration possibly increased with ritonavir
Anxiolytics and hypnotics: increased sedative effects.
Atomoxetine: increased risk of ventricular arrhythmias.
Beta-blockers: enhanced hypotensive effect; increased risk of ventricular arrhythmias with sotalol - avoid.
Cytotoxics: increased risk of ventricular arrhythmias with arsenic trioxide and possibly ceritinib.
Desferrioxamine: avoid concomitant use.
Diuretics: enhanced hypotensive effect.
Hormone antagonists: increased risk of ventricular arrhythmias with tamoxifen - avoid.
Lithium: increased risk of extrapyramidal side effects and possibly neurotoxicity.
Pentamidine: increased risk of ventricular arrhythmias - avoid.
Tacrolimus: increased risk of ventricular arrhythmias - avoid.

Metabolism

Extensively metabolised in the liver, and undergoes oxidation, dealkylation, demethylation and hydroxylation by cytochrome P450 isoenzymes 1A2 and 3A4, and to a lesser extent by 2C19. The metabolites are inactive. About 75% of a dose is excreted in the urine, with 1% being excreted unchanged; 11% appears in the faeces.