Antipsychotic

Prochlorperazine

Also called Compazine, Stemzine, Buccastem, Stemetil, Phenotil, Prochlorpromazine, Chlormeprazine, Chlorperazine

Original Wikipedia articleen.wikipedia.org/wiki/Prochlorperazine revision used (24 October 2026)

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Part of the metabolic pathway of Prochlorperazine. See the timeline on the metabolic highway.

Enzymes that break it down: CYP2D6 and CYP3A4. Wikipedia’s drug infobox says: “Mainly Liver (CYP2D6 and/or CYP3A4)” (revision 1373298496).

Common dose · Oral5–20 mg PW

Onset30–45 minutes PW

Total4–8 hours PW

Dosage

Light

Common

Strong

02520mg

Oral bands as drawn from PsychonautWiki's ranges below. The table is the source of truth.

Oral

Source	Threshold	Light	Common	Strong	Heavy
PsychonautWiki	2 mg PW	2.5–5 mg PW	5–20 mg PW	20–40 mg PW	–

What dose are you on? (self-reported, unverified)

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Duration

Route · source	Onset	Come-up	Peak	Offset	Total	After-effects
Oral · PsychonautWiki	30–45 minutes PW	–	–	–	4–8 hours PW	–

Mixing

Acute combinations: what happens when these are taken close together. Entries backed by a medical journal or agency are listed first.

Backed by medical journals

Awaiting sourcePeer-reviewed reports on acute combinations, from PubMed and the journals the harm reduction sites cite.

Risks and toxicity

Nervous system side effects have been associated with the use of prochlorperazine. Extrapyramidal side effects such as acute dystonic reactions, pseudoparkinsonism (not to be confused with Parkinson's disease), or akathisia can affect 2% of patients at low doses, whereas higher doses may affect as many as 40% of patients.[10][11] PW

Prochlorperazine can also cause a life-threatening condition called neuroleptic malignant syndrome (NMS). Some symptoms of NMS include a high fever, stiff muscles, confusion, irregular pulse or blood pressure, a fast heart rate (tachycardia), sweating, or irregular heart rhythms (arrhythmias). PW

Lethal dosage

The lethal dosage of this compound is unknown. Symptoms of overdose, however, may include agitation, coma, confusion, difficulty breathing, fainting, irregular heartbeat, loss of consciousness, muscle spasms, uncontrolled muscle movements, restlessness, seizures, severe constipation, stomach pain, severe drowsiness, dizziness, tremors, or trouble urinating. PW

It is strongly recommended that one use harm reduction practices when using this drug. PW

Tolerance and addiction potential

As with other antipsychotics, dependence can be present with long-term use and is both physical and psychological dependence. When physical dependence has developed, withdrawal symptoms may occur if a person suddenly stops their usage. PW

Median lethal dose (LD50) in animals

Quoted from PubChem's Non-Human Toxicity Values, which come from the Hazardous Substances Data Bank (HSDB). PubChem describes them as: “Quantitative non-human toxicity values (e.g., lethal dose) for this compound. The data shown here are mostly for lab animals (e.g., rat, mouse, guinea pig, and rabbit).” and defines the “LD50 (median lethal dose, the estimated amount of a chemical expected to kill 50% of test animals in a single dose)”. PC

LD50 (as the source gives it)	Reference
LD50 Rat oral 1800 mg/kg PC	Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 3054 (via HSDB record 3171)
LD50 Mouse oral 400 mg/kg PC	Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 3054 (via HSDB record 3171)
LD50 Mouse ip 120 mg/kg PC	Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 3054 (via HSDB record 3171)
LD50 Mouse sc 400 mg/kg PC	Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 3054 (via HSDB record 3171)

Testing

Awaiting sourceReagent reactions and test kit guidance from a harm reduction testing service.

Effects

Awaiting sourceSubjective and physical effects from PsychonautWiki or TripSit.

Overview

Prochlorperazine (Compazine, Stemzine, Buccastem M, Stemetil, Phenotil) is a dopaminergic D2 receptor antagonist that belongs to the phenothiazine class of antipsychotic agents that are used for the treatment of nausea and vertigo. It is also a highly potent typical antipsychotic and is 10–20× more potent than chlorpromazine. It is also used to treat migraine headaches.[1] PW

Prochlorperazine, formerly sold under the brand name Compazine among others, is a medication used to treat nausea, migraines, schizophrenia, psychosis and anxiety. It is a less preferred medication for anxiety. It may be taken by mouth, rectally, injection into a vein, or injection into a muscle.[2–6] WP

Common side effects include sleepiness, blurry vision, low blood pressure, and dizziness. Serious side effects may include movement disorders including tardive dyskinesia and neuroleptic malignant syndrome. Use in pregnancy and breastfeeding is generally not recommended. It is a typical antipsychotic which is believed to work by reducing the action of dopamine in the brain.[3][7] WP

Prochlorperazine was approved for medical use in the United States in 1956. It is available as a generic medication. In 2020, it was the 355th most commonly prescribed medication in the United States, with more than 600 thousand prescriptions.[3][4][8][9] WP

History

Awaiting sourceHistory and culture from Wikipedia or PsychonautWiki, with their citations.

Legal status

Australia: The substance is Schedule 3, meaning it is available with the advice of a pharmacist without a prescription. PW⚠ PsychonautWiki itself has flagged this text: citation needed.
United Kingdom: The drug is available over the counter as a pharmacy medicine and as a prescription medication. The OTC brand is Buccastem M, a buccal delivery system of prochlorperazine for motion sickness or nausea.[12] PW
United States: Prochlorperazine is available only through prescription. PW⚠ PsychonautWiki itself has flagged this text: citation needed.

Society and culture

In the United Kingdom, prochlorperazine is available for the treatment of nausea caused by migraine as a tablet dissolved in the mouth, and in Australia as a tablet swallowed whole. In the UK, it is available via a prescription and as a pharmacy medicine, meaning it does not require a prescription but is only available after talking with a pharmacist.[13][14] WP

Marketing

Prochlorperazine is available as tablets, suppositories, and in an injectable form.[15] WP

As of September 2017 it was marketed under the trade names Ametil, Antinaus, Buccastem, Bukatel, Chlormeprazine, Chloropernazine, Compazine, Compro, Daolin, Dhaperazine, Emedrotec, Emetiral, Eminorm, Lotamin, Mitil, Mormal, Nautisol, Novamin, Novomit, Proazine, Procalm, Prochlorperazin, Prochlorperazine, Prochlorpérazine, Prochlorperazinum, Prochlozine, Proclorperazina, Promat, Promin, Promtil, Roumin, Scripto-metic, Seratil, Stemetil, Steremal, Vergon, Vestil, and Volimin.[15][16] WP

Historical formulations

Prochlorperazine was combined with paracetamol and marketed for humans as the combination drug Vestil-A; it was combined with isopropamide (brand name Darbazine) as a combination drug for veterinary use.[15] WP⚠ Part of this sentence could not be copied from the source. Open the source to read it in full.

Until 1981, a combination diet pill composed of prochlorperazine and dextroamphetamine was marketed as Eskatrol in the United States by Smith, Kline & French Laboratories. WP

Pharmacology

Prochlorperazine is thought to exert its antipsychotic effects by blocking dopamine receptors.[21] WP

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. Hyperprolactinemia 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. WP

Following intramuscular injection, the antiemetic action is evident within 5 to 10 minutes and lasts for three to four hours. Rapid action is also noted after buccal treatment. With oral dosing, the start of action is delayed but the duration is somewhat longer (approximately six hours). WP

Receptor binding · Wikipedia

Prochlorperazine

col1	col2	col3	col4
5-HT1A	5,888	Human	[17] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
5-HT2A	7.24	Human	[17] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
5-HT2C	123	Human	[17] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
5-HT₃	1349	Human	[17] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
5-HT₆	148	Human	[17] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
5-HT₇	6,760	Human	[17] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
α₁	24	Human	[18] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
α₂	1700	Human	[18] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
M₁	776	Human	[17] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
M₂	1413	Human	[17] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
D₁	251	Human	[17] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
D₂	2.24	Human	[17] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
D₃	1.82	Human	[17] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
D₄	5.37	Human	[17] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
H₁	6.03	Human	[19] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
H₃	17,378	Human	[19] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
H₄	17783	Human	[19] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
DAT	589	Human	[17] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.
NET	600	Rat	[20] WP⚠ This row of the source table has a different number of cells than its headings, so columns may not line up.

Chemistry

Formula: C20H24ClN3S PC
CAS number: 58-38-8 PC
Molar mass (g/mol): 373.9 PC
IUPAC name (computed by PubChem): 2-chloro-10-[3-(4-methylpiperazin-1-yl)propyl]phenothiazine PC
SMILES: CN1CCN(CC1)CCCN2C3=CC=CC=C3SC4=C2C=C(C=C4)Cl PC
InChIKey: WIKYUJGCLQQFNW-UHFFFAOYSA-N PC
PubChem CID: 4917

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Pop culture

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References

Other Husseini, A; Gianakos, D (February 2006). "The 15-Minute Visit". Patient Care 40: 9–10
Other Side Effects of Compazine (Prochlorperazine), Warnings, Uses
Other Prochlorperazine Monograph for Professionals
Other British national formulary: BNF 76. 2018
Journal / agency Orr SL, Friedman BW, Christie S, Minen MT, Bamford C, Kelley NE, Tepper D. Management of Adults With Acute Migraine in the Emergency Department: The American Headache Society Evidence Assessment of Parenteral Pharmacotherapies. Headache. June 2016. doi:10.1111/head.12835 · PMID 27300483
Journal / agency Din L, Preuss CV. StatPearls [Internet]. March 2022. PMID 30725768
Other Prochlorperazine Use During Pregnancy
Other The Top 300 of 2020
Other Prochlorperazine - Drug Usage Statistics
Other Brown, T. M., Stoudemire, A. Psychiatric Side Effects of Prescription and Over-the-counter Medications: Recognition and Management. 1998
Other http://www.drugs.com/sfx/procot-side-effects.html
Other Package leaflet: Information for the user. Buccastem® M Buccal Tablets (PROCHLORPERAZINE MALEATE 3 MG, EQUIVALENT TO 1.85 MG PROCHLORPERAZINE BASE) Alliance Pharmaceuticals, LTD. (2016) #l:Buccastem M use guide, last revised in January 2016..pdf
Other Buccastem M - Summary of Product Characteristics (SPC) - (eMC). 16 February 2016
Other Medicines information
Other Prochlorperazine international brands
Other Compazine (Prochlorperazine) Patient Information: Side Effects and Drug Images at RxList
Journal / agency Silvestre JS, Prous J. Research on adverse drug events. I. Muscarinic M3 receptor binding affinity could predict the risk of antipsychotics to induce type 2 diabetes. Methods and Findings in Experimental and Clinical Pharmacology. June 2005. doi:10.1358/mf.2005.27.5.908643 · PMID 16082416
Journal / agency Richelson E, Nelson A. Antagonism by neuroleptics of neurotransmitter receptors of normal human brain in vitro. European Journal of Pharmacology. August 1984. doi:10.1016/0014-2999(84)90478-3 · PMID 6149136
Journal / agency Appl H, Holzammer T, Dove S, Haen E, Strasser A, Seifert R. Interactions of recombinant human histamine H₁R, H₂R, H₃R, and H₄R receptors with 34 antidepressants and antipsychotics. Naunyn-Schmiedeberg's Archives of Pharmacology. February 2012. doi:10.1007/s00210-011-0704-0 · PMID 22033803
Journal / agency Richelson E, Pfenning M. Blockade by antidepressants and related compounds of biogenic amine uptake into rat brain synaptosomes: most antidepressants selectively block norepinephrine uptake. European Journal of Pharmacology. September 1984. doi:10.1016/0014-2999(84)90403-5 · PMID 6499924
Other Ebadi MS. Desk Reference of Clinical Pharmacology. 2007

Text and values on this page are quoted from PsychonautWiki (CC BY-SA 4.0), Wikipedia (CC BY-SA 4.0), PubChem (public domain). Each value links to the exact revision it came from.