Systematic (IUPAC) name
Clinical data
AHFS/ monograph
MedlinePlus a682116
Pregnancy cat. C (Au, U.S.)
Legal status -only (US) OTC/POM (UK)
Routes Oral, buccal, rectal, IM
Pharmacokinetic data
Bioavailability not exactly known, but substantial
Protein binding 91–99%
Metabolism Mainly hepatic (CYP2D6 and/or CYP3A4)
Half-life 4–8 hoursS, differs with the method of administration
Excretion Biliary, (colored) inactive metabolites in urine
CAS number 58-38-8 YesY
ATC code N05AB04
PubChem CID 4917
DrugBank APRD00624
ChemSpider 4748 YesY
KEGG D00493 YesY
Chemical data
Formula C20H24ClN3S 
Mol. mass 373.943 g/mol
SMILES eMolecules & PubChem
 N(what is this?)  (verify)

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, 10-20x 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 anti-psychotics (neuroleptics).[1] 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, etc.

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 and vomiting and vertigo as follows:

  1. To alleviate the symptoms of vertigo[2]
  2. As an antiemetic, particularly for nausea and vomiting caused by chemotherapy, radiation therapy and in the pre- and postoperative setting[3]
  3. In the UK, prochlorperazine maleate is available as Buccastem M in buccal form as an over-the-counter treatment for migraine.[4] In this indication it blocks the chemoreceptor trigger zone (CTZ) in the brain, which is responsible for causing severe nausea and vomiting. Its OTC use is strictly restricted to a maximum of 2 days, because of the potentially severe side effects of prochlorperazine, which mandate supervision by a health care provider.
  4. In the UK prochlorperazine maleate has been prescribed to alleviate the symptoms of labyrinthitis, which include not only nausea and vertigo, but spatial and temporal 'jerking' and distortion[5]


Prochlorperazine is thought to exert its antipsychotic effects by blocking dopamine receptors.[6]

Formulations and pharmacokinetics

Prochlorperazine is available as an oral liquid, tablets, cream for trans dermal(compounding pharmacy), and suppositories, as well as in an injectable form.

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).

It is available in Egypt under the brand name Emedrotec buccal adhesive tablets by Eva pharma.

There is an inhaled form of prochlorperazine under development by Alexza Pharmaceuticals, currently[when?] in Phase II clinical trials.[7]

Side effects

Hypersensitivities to prochlorperazine can occur and there is cross-reactivity with other drugs in the phenothiazine class. Symptoms of a reaction include dyskinesia (unusual, uncontrollable body or face movements, including abnormal movements of the tongue, also known as dystonia), seizures and seizure-like symptoms in individuals who have never had a seizure before. Long-term delay of medical treatment can lead to long-term effects. In extreme cases, it has been known to produce permanent damage to the lower jaw and the jaw joint due to extended seizure symptoms.[8]

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, irregular heart rhythms (arrhythmias). VA and FDA research shows injection site reaction.


Prochlorpherazine (2-chloro-10-[3-(4-methyl-1-piperazinyl) propyl]-phenothiazine) is prepared by the alkylation of 2-chlorophenothiazine using 4-methyl-1-piperazinyl)propyl-3-chloride in the presence of sodamide, or alkylation of 2-chloro-10-[(3-chloropropyl)]phenothiazine using 1-methylpiperazine.


  1. ^ Casey JF, Lasky JJ, Klett CJ, Hollister LE (August 1960). "Treatment of schizophrenic reactions with phenothiazine derivatives. A comparative study of chlorpromazine, triflupromazine, mepazine, prochlorperazine, perphenazine, and phenobarbital". American Journal of Psychiatry 117: 97–105. doi:10.1176/appi.ajp.117.2.97 (inactive 2010-03-18). PMID 13808146. 
  2. ^ Benson AJ (June 1969). "Effect of diphenidol and prochlorperazine on semicircular canal function in man". Aerospace Medicine 40 (6): 589–95. PMID 4891872. 
  3. ^ Gralla RJ, Osoba D, Kris MG, et al. (September 1999). "Recommendations for the use of antiemetics: evidence-based, clinical practice guidelines". Journal of Clinical Oncology 17 (9): 2971–94. PMID 10561376. Retrieved 2009-06-21. 
  4. ^ Siow HC, Young WB, Silberstein SD (April 2005). "Neuroleptics in headache". Headache 45 (4): 358–71. doi:10.1111/j.1526-4610.2005.05074.x. PMID 15836574. 
  5. ^ Coatesworth AP (November 2000). "Assessment and treatment of dizziness". Journal of Neurology, Neurosurgery, and Psychiatry 69 (5): 706. doi:10.1136/jnnp.69.5.706. PMC 1763384. PMID 11184241. Retrieved 2009-06-21. 
  6. ^ Manuchair S. Ebadi, Desk reference of clinical pharmacology. 2007
  7. ^ "Alexza Announces Agreement to Acquire Symphony Allegro, Including All Rights to AZ-004, AZ-104 and AZ-002" (Press release). Alexza Pharmaceuticals. 2009-06-15. Retrieved 2009-11-29. 
  8. ^ "". Retrieved 2010-04-21. 

External links