Promethazine

Promethazine
Clinical data
Trade namesPhenergan, others[1]
AHFS/Drugs.comMonograph
MedlinePlusa682284
License data
Pregnancy
category
  • AU: C
Routes of
administration		By mouth, rectal, intravenous, intramuscular, topical
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailability88% absorbed but after first-pass metabolism reduced to 25% absolute bioavailability[2]
Protein binding93%
MetabolismLiver glucuronidation and sulfoxidation
Elimination half-life10–19 hours[2][3]
ExcretionKidney and Bile duct
Identifiers
  • (RS)-N,N-Dimethyl-1-(10H-phenothiazin-10-yl)propan-2-amine
CAS Number
PubChem CID
IUPHAR/BPS
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard100.000.445 Edit this at Wikidata
Chemical and physical data
FormulaC17H20N2S
Molar mass284.42 g·mol−1
3D model (JSmol)
ChiralityRacemic mixture
  • S2c1ccccc1N(c3c2cccc3)CC(N(C)C)C
  • InChI=1S/C17H20N2S/c1-13(18(2)3)12-19-14-8-4-6-10-16(14)20-17-11-7-5-9-15(17)19/h4-11,13H,12H2,1-3H3 checkY
  • Key:PWWVAXIEGOYWEE-UHFFFAOYSA-N checkY
  (verify)

Promethazine, sold under the brand name Phenergan among others, is a first-generation antihistamine, sedative, and antiemetic used to treat allergies, insomnia, and nausea. It may also help with some symptoms associated with the common cold[4] and may also be used for sedating people who are agitated or anxious, an effect that has led to some recreational use (especially with codeine).[5][6][7] Promethazine is taken by mouth (oral), as a rectal suppository, or by injection into a muscle (IM).[4]

Common side effects of promethazine include confusion and sleepiness;[4] consumption of alcohol or other sedatives can make these symptoms worse.[4] It is unclear if use of promethazine during pregnancy or breastfeeding is safe for the fetus.[4][6] Use of promethazine is not recommended in those less than two years old, due to potentially negative effects on breathing.[4] Use of promethazine by injection into a vein is not recommended, due to potential skin damage.[4] Promethazine is in the phenothiazine family of medications.[4] It is also a strong anticholinergic, which produces its sedative effects. This also means high or toxic doses can act as a deliriant.[8]

Promethazine was made in the 1940s by a team of scientists from Rhône-Poulenc laboratories.[9] It was approved for medical use in the United States in 1951.[4] It is a generic medication and is available under many brand names globally.[1] In 2022, it was the 198th most commonly prescribed medication in the United States, with more than 2 million prescriptions.[10][11] In 2022, the combination with dextromethorphan was the 260th most commonly prescribed medication in the United States, with more than 1 million prescriptions.[10][12]

  1. ^ a b "Promethazine international brands". Drugs.com. Retrieved 17 July 2017.
  2. ^ a b Cite error: The named reference pmid10965395 was invoked but never defined (see the help page).
  3. ^ Paton DM, Webster DR (1985). "Clinical pharmacokinetics of H1-receptor antagonists (the antihistamines)". Clinical Pharmacokinetics. 10 (6): 477–97. doi:10.2165/00003088-198510060-00002. PMID 2866055. S2CID 33541001.
  4. ^ a b c d e f g h i "Promethazine Hydrochloride Monograph for Professionals". Drugs.com. American Society of Health-System Pharmacists. Retrieved 24 October 2018.
  5. ^ Cite error: The named reference lean was invoked but never defined (see the help page).
  6. ^ a b British national formulary : BNF 74 (74 ed.). British Medical Association. 2017. p. 276. ISBN 978-0-85711-298-9.
  7. ^ Malamed SF (2009). Sedation: A Guide to Patient Management. Elsevier Health Sciences. p. 113. ISBN 978-0-323-07596-1.
  8. ^ Page CB, Duffull SB, Whyte IM, Isbister GK (February 2009). "Promethazine overdose: clinical effects, predicting delirium and the effect of charcoal". QJM. 102 (2): 123–131. doi:10.1093/qjmed/hcn153. PMID 19042969. S2CID 17677540.
  9. ^ Li JJ (2006). Laughing Gas, Viagra, and Lipitor: The Human Stories behind the Drugs We Use. United Kingdom: Oxford University Press. p. 146. ISBN 978-0-19-988528-2. Retrieved 9 July 2016.
  10. ^ a b "The Top 300 of 2022". ClinCalc. Archived from the original on 30 August 2024. Retrieved 30 August 2024.
  11. ^ "Promethazine Drug Usage Statistics, United States, 2013 - 2022". ClinCalc. Retrieved 30 August 2024.
  12. ^ "Dextromethorphan; Promethazine Drug Usage Statistics, United States, 2013 - 2022". ClinCalc. Retrieved 30 August 2024.