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Clinical data
AHFS/ Monograph
MedlinePlus a682116
Routes of
Oral, buccal, rectal, IM, IV
ATC code
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
CAS Number
PubChem CID
ECHA InfoCard 100.000.345
Chemical and physical data
Formula C20H24ClN3S
Molar mass 373.943 g/mol
3D model (Jmol)

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.[1] Intravenous administration can be used to treat status migrainosus.


Prochlorperazine is a phenothiazine drug. Most drugs in this category are used as antipsychotics (neuroleptics).[2] 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.[citation needed]

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-term) treatment of nausea, vomiting, and vertigo as follows:

  1. To alleviate the symptoms of vertigo[3]
  2. As an antiemetic, particularly for nausea and vomiting caused by chemotherapy, radiation therapy and in the pre- and postoperative setting[4]
  3. In the UK, prochlorperazine maleate is available as Buccastem M in buccal form as an over-the-counter treatment for migraine.[5] In this indication it blocks the chemoreceptor trigger zone (CTZ) in the brain, which is responsible for causing severe nausea and vomiting. Its over the counter (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[6]


Prochlorperazine is thought to exert its antipsychotic effects by blocking dopamine receptors.[7]

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.

Formulations and pharmacokinetics[edit]

5mg oral tablet of Prochlorperazine

Prochlorperazine is available as an oral liquid, tablets, cream for transdermal (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 (November 2009 at the time of writing) in Phase II clinical trials.[8]

Side effects[edit]

Nervous system side effects have been associated with the use of prochlorperazine. Extrapyramidal side effects such as acute dystonic reactions, pseudoparkinsonism, or akathisia can affect 2% of patients at low doses, whereas higher doses may affect as many as 40% of patients.[9][10]

Prochlorperazine can also cause a life-threatening condition called neuroleptic malignant syndrome (NMS). Some symptoms of NMS include high fever, stiff muscles, confusion, irregular pulse or blood pressure, fast heart rate (tachycardia), sweating, abnormal heart rhythms (arrhythmias). VA and FDA research show injection site reactions.


  1. ^ Husseini A, Gianakos D (February 2006). "The 15-Minute Visit". Patient Care. 40: 9–10. 
  2. ^ 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/ajp.117.2.97. PMID 13808146. 
  3. ^ Benson AJ (June 1969). "Effect of diphenidol and prochlorperazine on semicircular canal function in man". Aerospace Medicine. 40 (6): 589–95. PMID 4891872. 
  4. ^ Gralla RJ, Osoba D, Kris MG, Kirkbride P, Hesketh PJ, Chinnery LW, Clark-Snow R, Gill DP, Groshen S, Grunberg S, Koeller JM, Morrow GR, Perez EA, Silber JH, Pfister DG (September 1999). "Recommendations for the use of antiemetics: evidence-based, clinical practice guidelines". Journal of Clinical Oncology. 17 (9): 2971–94. doi:10.1200/jco.1999.17.9.2971 (inactive 2017-01-15). PMID 10561376. 
  5. ^ 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. 
  6. ^ 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 1763384Freely accessible. PMID 11184241. 
  7. ^ Manuchair S. Ebadi, Desk reference of clinical pharmacology. 2007
  8. ^ "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. 
  9. ^ Brown, Thomas Markham; Stoudemire, Alan (1998). "Antipsychotics". Psychiatric Side Effects of Prescription and Over-The-Counter Medications. American Psychiatric Publishing. p. 1946. ISBN 9780880488686. Retrieved 2013-01-18. 
  10. ^

External links[edit]