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Trade namesCompazine, others
  • 2-chloro-10-[3-(4-methyl-1-piperazinyl)propyl]-10H-phenothiazine
Clinical data
Drug classTypical antipsychotic[1]
Main usesNausea, schizophrenia, migraines, anxiety[1][2]
Side effectsSleepiness, blurry vision, low blood pressure, dizziness[1]
Routes of
By mouth, rectal, IM, IV
Defined daily dose100 mg (by mouth, rectal)[3]
50 mg (by injection)[3]
External links
License data
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
BioavailabilityUnknown, but presumed substantial
Protein binding91–99%
MetabolismMainly Liver (CYP2D6 and/or CYP3A4)
Elimination half-life4–8 hours, differs with the method of administration
ExcretionBiliary, (colored) inactive metabolites in urine
Chemical and physical data
Molar mass373.94 g·mol−1
3D model (JSmol)
  • Clc2cc1N(c3c(Sc1cc2)cccc3)CCCN4CCN(C)CC4
  • 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 checkY

Prochlorperazine, sold under the brand name Compazine among others, is a medication used to treat nausea, schizophrenia, migraines, and anxiety.[1][2][4] It is a less preferred medication for anxiety.[1] It may be taken by mouth, rectally, injection into a vein, or injection into a muscle.[1]

Common side effects include sleepiness, blurry vision, low blood pressure, and dizziness.[1] Serious side effects may include movement disorders including tardive dyskinesia and neuroleptic malignant syndrome.[1] Use in pregnancy and breastfeeding is generally not recommended.[5] It is a typical antipsychotic which is believed to work by affecting levels of dopamine in the brain.[1]

Prochlorperazine was approved for medical use in the United States in 1956.[1] It is available as a generic medication.[2] A dose in the United Kingdom costs the NHS about £0.04 as of 2019.[2] In the United States the wholesale cost of this amount is about US$0.24.[6] In 2016, it was the 288th most commonly prescribed medication in the United States with more than a million prescriptions.[7]

Medical uses


Prochlorperazine is used to prevent vomiting caused by chemotherapy, radiation therapy and in the pre- and postoperative setting.[8] A 2015 Cochrane review found no differences in efficacy among drugs commonly used for this purpose in emergency rooms.[9]


Prochlorperazine, generally by intravenous, is used to treat migraine.[10][11] Such use is recommended by The American Headache Society.[4] Compared with metoclopramide, PCP had an almost 3 times higher odds of headache relief within the 60 minutes of PCP administration.[10]


In the UK prochlorperazine maleate has been used for labyrinthitis, which include not only nausea and vertigo, but spatial and temporal 'jerking' and distortion.[12]


The defined daily dose is 100 mg by mouth or rectum and 50 mg by injection.[3]

Side effects

Sedation is very common, and extrapyramidal side effects are common and include restlessness, dystonic reactions, pseudoparkinsonism, and akathisia; the extrapyramidal symptoms can affect 2% of people at low doses, whereas higher doses may affect as many as 40% of people.[13][14]

Prochlorperazine can also cause a life-threatening condition called neuroleptic malignant syndrome (NMS). Some symptoms of NMS include high fever, stiff muscles, neck muscle spasm, confusion, irregular pulse or blood pressure, fast heart rate (tachycardia), sweating, abnormal heart rhythms (arrhythmias). Research from the Veterans Administration and United States Food and Drug Administration show injection site reactions. Adverse effects are similar in children.[8]


The British National Formulary recommends a gradual withdrawal when discontinuing antipsychotics to avoid acute withdrawal syndrome or rapid relapse.[15] Symptoms of withdrawal commonly include nausea, vomiting, and loss of appetite.[16] Other symptoms may include restlessness, increased sweating, and trouble sleeping.[16] Less commonly there may be a feeling of the world spinning, numbness, or muscle pains.[16] Symptoms generally resolve after a short period of time.[16]

There is tentative evidence that discontinuation of antipsychotics can result in psychosis.[17] It may also result in reoccurrence of the condition that is being treated.[18] Rarely tardive dyskinesia can occur when the medication is stopped.[16]


Site Ki (nM) Species Ref
5-HT1A 5,888 Human [19]
5-HT2A 7.24 Human [19]
5-HT2C 123 Human [19]
5-HT3 1349 Human [19]
5-HT6 148 Human [19]
5-HT7 6,760 Human [19]
α1 24 Human [20]
α2 1700 Human [20]
M1 776 Human [19]
M2 1413 Human [19]
D1 251 Human [19]
D2 2.24 Human [19]
D3 1.82 Human [19]
D4 5.37 Human [19]
H1 6.03 Human [21]
H3 17,378 Human [21]
H4 17783 Human [21]
DAT 589 Human [19]
NET 600 Rat [22]

Prochlorperazine is thought to exert its antipsychotic effects by blocking dopamine receptors.[23]

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.

Following intramuscular injection, the antiemetic action is evident within 5 to 10 minutes and lasts for 3 to 4 hours. Rapid action is also noted after buccal treatment. With oral dosing, the start of action is delayed but the duration somewhat longer (approximately 6 hours).

Society and culture

In the UK, prochlorperazine is available for the treatment of nausea caused by migraine as a tablet dissolved in the mouth; it is sold as a "pharmacy medicine", meaning it does not require a prescription but is only available after talking with a pharmacist.[24][25]


Prochlorperazine is available as tablets, suppositories, and in an injectable form.[26]

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.[26][27]

It was also marketed at that time as a combination drug for humans with paracetamol as Vestil-A, as a combination drug for veterinary use, with isopropamide as Darbazine.[26]


Alexza Pharmaceuticals studied an inhaled form of prochlorperazine for the treatment of migraine through Phase II trials under the development name AT-001; development was discontinued in 2011.[28]


  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 "Prochlorperazine Monograph for Professionals". American Society of Health-System Pharmacists. Archived from the original on 20 April 2019. Retrieved 3 March 2019.
  2. 2.0 2.1 2.2 2.3 British national formulary : BNF 76 (76 ed.). Pharmaceutical Press. 2018. pp. 385–386. ISBN 9780857113382.
  3. 3.0 3.1 3.2 "WHOCC - ATC/DDD Index". Archived from the original on 6 August 2020. Retrieved 7 September 2020.
  4. 4.0 4.1 Orr, SL; Friedman, BW; Christie, S; Minen, MT; Bamford, C; Kelley, NE; Tepper, D (June 2016). "Management of Adults With Acute Migraine in the Emergency Department: The American Headache Society Evidence Assessment of Parenteral Pharmacotherapies". Headache. 56 (6): 911–40. doi:10.1111/head.12835. PMID 27300483.
  5. "Prochlorperazine Use During Pregnancy". Archived from the original on 20 April 2019. Retrieved 3 March 2019.
  6. "NADAC as of 2019-02-27". Centers for Medicare and Medicaid Services. Archived from the original on 2019-03-06. Retrieved 3 March 2019.
  7. "Prochlorperazine - Drug Usage Statistics". ClinCalc. Archived from the original on 21 June 2020. Retrieved 11 April 2020.
  8. 8.0 8.1 Lau Moon Lin, M; Robinson, PD; Flank, J; Sung, L; Dupuis, LL (June 2016). "The Safety of Prochlorperazine in Children: A Systematic Review and Meta-Analysis". Drug Safety. 39 (6): 509–16. doi:10.1007/s40264-016-0398-9. PMID 26884326.
  9. Furyk, JS; Meek, RA; Egerton-Warburton, D (28 September 2015). "Drugs for the treatment of nausea and vomiting in adults in the emergency department setting". The Cochrane Database of Systematic Reviews (9): CD010106. doi:10.1002/14651858.CD010106.pub2. PMC 6517141. PMID 26411330.
  10. 10.0 10.1 Golikhatir I, Cheraghmakani H, Bozorgi F, Jahanian F, Sazgar M, Montazer SH (2019). "The Efficacy and Safety of Prochlorperazine in Patients With Acute Migraine: A Systematic Review and Meta-Analysis". Headache. 59 (5): 682–700. doi:10.1111/head.13527. PMID 30990883.{{cite journal}}: CS1 maint: uses authors parameter (link)
  11. Patniyot, IR; Gelfand, AA (January 2016). "Acute Treatment Therapies for Pediatric Migraine: A Qualitative Systematic Review". Headache. 56 (1): 49–70. doi:10.1111/head.12746. PMID 26790849.
  12. Coatesworth AP (November 2000). "Assessment and treatment of dizziness". Journal of Neurology, Neurosurgery, and Psychiatry. 69 (5): 706–707. doi:10.1136/jnnp.69.5.706. PMC 1763384. PMID 11184241.
  13. Brown, Thomas Markham; Stoudemire, Alan (1998). "Antipsychotics". Psychiatric Side Effects of Prescription and Over-The-Counter Medications. American Psychiatric Publishing. p. 1946. ISBN 9780880488686.
  14. "Procot Side Effects in Detail". Archived from the original on 2018-11-01. Retrieved 2018-01-23.
  15. Joint Formulary Committee, BMJ, ed. (March 2009). "4.2.1". British National Formulary (57 ed.). United Kingdom: Royal Pharmaceutical Society of Great Britain. p. 192. ISBN 978-0-85369-845-6. Withdrawal of antipsychotic drugs after long-term therapy should always be gradual and closely monitored to avoid the risk of acute withdrawal syndromes or rapid relapse.
  16. 16.0 16.1 16.2 16.3 16.4 Haddad, Peter; Haddad, Peter M.; Dursun, Serdar; Deakin, Bill (2004). Adverse Syndromes and Psychiatric Drugs: A Clinical Guide. OUP Oxford. pp. 207–216. ISBN 9780198527480. Archived from the original on 2021-04-14. Retrieved 2020-05-12.
  17. Moncrieff J (July 2006). "Does antipsychotic withdrawal provoke psychosis? Review of the literature on rapid onset psychosis (supersensitivity psychosis) and withdrawal-related relapse". Acta Psychiatrica Scandinavica. 114 (1): 3–13. doi:10.1111/j.1600-0447.2006.00787.x. PMID 16774655.
  18. Sacchetti, Emilio; Vita, Antonio; Siracusano, Alberto; Fleischhacker, Wolfgang (2013). Adherence to Antipsychotics in Schizophrenia. Springer Science & Business Media. p. 85. ISBN 9788847026797. Archived from the original on 2021-04-14. Retrieved 2020-05-12.
  19. 19.00 19.01 19.02 19.03 19.04 19.05 19.06 19.07 19.08 19.09 19.10 19.11 19.12 Silvestre, J.S.; Prous, J. (2005). "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. 27 (5): 289. doi:10.1358/mf.2005.27.5.908643. ISSN 0379-0355. Archived from the original on 2020-07-31. Retrieved 2020-05-05.
  20. 20.0 20.1 Richelson, Elliott; Nelson, Albert (August 1984). "Antagonism by neuroleptics of neurotransmitter receptors of normal human brain in vitro". European Journal of Pharmacology. 103 (3–4): 197–204. doi:10.1016/0014-2999(84)90478-3. PMID 6149136.
  21. 21.0 21.1 21.2 Appl, Heidrun; Holzammer, Tobias; Dove, Stefan; Haen, Ekkehard; Straßer, Andrea; Seifert, Roland (February 2012). "Interactions of recombinant human histamine H1, H2, H3, and H4 receptors with 34 antidepressants and antipsychotics". Naunyn-Schmiedeberg's Archives of Pharmacology. 385 (2): 145–170. doi:10.1007/s00210-011-0704-0. ISSN 0028-1298. PMID 22033803.
  22. Richelson, Elliott; Pfenning, Michael (September 1984). "Blockade by antidepressants and related compounds of biogenic amine uptake into rat brain synaptosomes: Most antidepressants selectively block norepinephrine uptake". European Journal of Pharmacology. 104 (3–4): 277–286. doi:10.1016/0014-2999(84)90403-5.
  23. Manuchair S. Ebadi, Desk reference of clinical pharmacology. 2007
  24. "Buccastem M - Summary of Product Characteristics (SPC) - (eMC)". UK Electronic Medicines Compendium. 16 February 2016. Archived from the original on 10 September 2016. Retrieved 19 September 2017.
  25. "Medicines information". NHS Choices. Archived from the original on 22 October 2017. Retrieved 19 September 2017.
  26. 26.0 26.1 26.2 "Prochlorperazine international brands". Archived from the original on 22 September 2017. Retrieved 19 September 2017.
  27. "Compazine (Prochlorperazine) Patient Information: Side Effects and Drug Images at RxList". RxList. Archived from the original on 2018-01-22. Retrieved 2018-01-22.
  28. Chua, AL; Silberstein, S (September 2016). "Inhaled drug therapy development for the treatment of migraine". Expert Opinion on Pharmacotherapy. 17 (13): 1733–43. doi:10.1080/14656566.2016.1203901. PMID 27416108.

External links

External sites: