Clinical data
AHFS/Drugs.comMicromedex Detailed Consumer Information
Drug classTypical antipsychotic
ATC code
Pharmacokinetic data
Protein binding94%
Elimination half-life20-40 hr
  • N,N-dimethyl-3-(10H-phenothiazin-10-yl)-propan-1-amine
CAS Number
PubChem CID
CompTox Dashboard (EPA)
ECHA InfoCard100.000.347 Edit this at Wikidata
Chemical and physical data
Molar mass284.42 g·mol−1
3D model (JSmol)
  • CN(C)CCCN1c2ccccc2Sc3c1cccc3
  • InChI=1S/C17H20N2S/c1-18(2)12-7-13-19-14-8-3-5-10-16(14)20-17-11-6-4-9-15(17)19/h3-6,8-11H,7,12-13H2,1-2H3 checkY

Promazine (brand name Sparine among others),[1] is used as a short-term add-on treatment for psychomotor agitation.[2][3] Its approved uses in people is limited, but is used as a tranquilizer in veterinary medicine.[2] It has weak antipsychotic effects but is generally not used to treat psychoses.[2]

It acts similar to chlorpromazine and causes sedation.[2] It has predominantly anticholinergic side effects, though extrapyramidal side effects are not uncommon. It belongs to the typical antipsychotic and phenothiazine class of drugs.[4]

Promazine was approved for medical use in the United States in the 1950s, although it is no longer commercially available there.[1][5]


Promazine is a short-term add-on treatment for psychomotor agitation.[3]

Adverse effects

Common side effects include agitation, absent menstruation, arrhythmias, constipation, drowsiness and dizziness, dry mouth, problems with erection, tiredness, milky nipple discharge, large breasts, high sugars, difficulty sleeping, low blood pressure, prolonged QT, fits, shaking, vomiting and weight gain, among others.[3]


In overdose, it may cause blood pressure to drop, lowering of body temperature, increased heart rate, and an irregular heart beat.[3]

Sudden death may occur, although rare.[3]

Other animals

Promazine, given as promazine hydrochloride, is one of the primary tranquilizers used by veterinarians as a pre-anaesthesia injection in horses.[6][7] It does not provide analgesia and is not a very strong sedative, hence it is used combined with opioids or α2 adrenoreceptor agonists, such as atropine, or both.[7][8] It can be used alone when performing a non-painful procedure such as the fitting a horseshoe.[8] Low blood pressure, fast heart rate and paralysis of the penis are side effects.[6] It is also an antiemetic, antispasmodic and hypothermic agent.[7] Additionally it is used to lower blood pressure in animals with laminitis and kidney failure.[7] It is available in the US for veterinary use under the names Promazine and Tranquazine.[citation needed]


  1. ^ a b "Promazine (Primazine, Prozine) | Davis's Drug Guide". Retrieved 6 August 2021.
  2. ^ a b c d Davis, Claire (2007). Enna, S.J.; Bylund, David B. (eds.). Promazine. Elsevier. pp. 1–6. ISBN 978-0-08-055232-3.
  3. ^ a b c d e "BNF". NICE. Retrieved 4 August 2021.
  4. ^ Pagliaro LA, Pagliaro AM (1999). "PPDR: Promazine". Psychologist's Neuropsychotropic Desk Reference. Philadelphia: Brunner/Mazel. p. 535. ISBN 978-1-138-00968-4.
  5. ^ "Drugs@FDA: FDA-Approved Drugs". New Drug Application (NDA): 010942 Sparine. U.S. Food and Drug Administration.
  6. ^ a b Hendrickson, Dean A. (2007). "2. Anaesthesia and fluid therapy". Techniques in Large Animal Surgery (3rd ed.). Blackwell Publishing. p. 16. ISBN 978-0-7817-8255-5.
  7. ^ a b c d "Promazine | Equimed - Horse Health Matters". EquiMed. 20 January 2014. Archived from the original on 4 August 2021. Retrieved 4 August 2021.
  8. ^ a b Ringer, Simone K.; Mama, Khursheed R. (2019). "23. Chemical restraint for standing procedures". In Auer, Jorg A.; Stick, John A. (eds.). Equine Surgery (5th ed.). St Louis, Missouri: Elsevier. pp. 351–352. ISBN 978-0-323-48420-6.