Prochlorperazine

Prochlorperazine

Clinical data
AHFS/Drugs.com	Monograph
MedlinePlus	a682116
Pregnancy category	C (Au, U.S.)
Routes of administration	Oral, buccal, rectal, IM, IV
ATC code	N05AB04 (WHO)
Legal status
Legal status	AU: S3 (Pharmacist only) UK: POM (Prescription only) but packs of 8 buccal tablets for nausea/vomiting associated with migraine are sold as pharmacy medicines US: ℞-only
Pharmacokinetic data
Bioavailability	Unknown, but presumed substantial
Protein binding	91–99%
Metabolism	Mainly hepatic (CYP2D6 and/or CYP3A4)
Biological half-life	4–8 hours, differs with the method of administration
Excretion	Biliary, (colored) inactive metabolites in urine
Identifiers
IUPAC name 2-chloro-10-[3-(4-methyl-1-piperazinyl)propyl]- 10H-phenothiazine
CAS Number	58-38-8 Y
PubChem CID	4917
IUPHAR/BPS	7279
DrugBank	DB00433 Y
ChemSpider	4748 Y
UNII	YHP6YLT61T
KEGG	D00493 Y
ChEBI	CHEBI:8435 Y
ChEMBL	CHEMBL728 Y
ECHA InfoCard	100.000.345
Chemical and physical data
Formula	C20H24ClN3S
Molar mass	373.943 g/mol
3D model (Jmol)	Interactive image
SMILES Clc2cc1N(c3c(Sc1cc2)cccc3)CCCN4CCN(C)CC4
InChI InChI=1S/C20H24ClN3S/c1-22-11-13-23(14-12-22)9-4-10-24-17-5-2-3-6-19(17)25-20-8-7-16(21)15-18(20)24/h2-3,5-8,15H,4,9-14H2,1H3 Y Key:WIKYUJGCLQQFNW-UHFFFAOYSA-N Y

Prochlorperazine (Compazine, Stemzine, Buccastem, Stemetil, Phenotil) is a dopamine (D₂) receptor antagonist that belongs to the phenothiazine class of antipsychotic agents that are used for the antiemetic treatment of nausea and vertigo. It is also a highly potent typical antipsychotic, 10–20 times more potent than chlorpromazine. It is also used to treat migraine headaches. Intravenous administration can be used to treat status migrainosus.

Prochlorperazine is a phenothiazine drug. Most drugs in this category are used as antipsychotics (neuroleptics). Neuroleptic means "nerve seizing", and describes the semi-paralyzing effect these drugs have on the brain and nervous system. Stemetil is no longer being manufactured for sale in Canada as an anti-psychotic, but it is still available for treatment of nausea.

It is now relatively seldom used for the treatment of psychosis and the manic phase of bipolar disorder. It has a prominent antiemetic/antivertiginoic activity and is most often used for the (short-time) treatment of nausea, vomiting, and vertigo as follows:

Prochlorperazine is thought to exert its antipsychotic effects by blocking dopamine receptors.

Prochlorperazine is analogous to chlorpromazine, both of these agents antagonize dopaminergic D₂ receptors in various pathways of the central nervous system. This D₂ blockade results in antipsychotic, antiemetic and other effects. Hyperprolactinaemia is a side effect of dopamine antagonists as blockade of D₂ receptors within the tuberoinfundibular pathway results in increased plasma levels of prolactin due to increased secretion by lactotrophs in the anterior pituitary.