Homatropine (Equipin, Isopto Homatropine) is an anticholinergic medication that is an antagonist at muscarinic acetylcholine receptors and thus the parasympathetic nervous system. It is used in eye drops as a cycloplegic (to temporarily paralyze accommodation), and as a mydriatic (to dilate the pupil).

Homatropine
Clinical data
AHFS/Drugs.comMonograph
MedlinePlusa601006
ATC code
Legal status
Legal status
  • In general: ℞ (Prescription only)
Identifiers
  • (N-Methyl-8-azabicyclo[3.2.1]oct-3-yl) 2-hydroxy-2-phenylacetate
CAS Number
PubChem CID
DrugBank
ChemSpider
UNII
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard100.001.561 Edit this at Wikidata
Chemical and physical data
FormulaC16H21NO3
Molar mass275.348 g·mol−1
3D model (JSmol)
  • CN3[C@H]1CC[C@@H]3C[C@@H](C1)OC(=O)C(O)c2ccccc2
  • InChI=1S/C16H21NO3/c1-17-12-7-8-13(17)10-14(9-12)20-16(19)15(18)11-5-3-2-4-6-11/h2-6,12-15,18H,7-10H2,1H3/t12-,13+,14+,15? checkY
  • Key:ZTVIKZXZYLEVOL-MCOXGKPRSA-N checkY
 ☒NcheckY (what is this?)  (verify)

The related chemical compound homatropine methylbromide (methylhomatropine) is a different medication. Homatropine is less potent than atropine and has a shorter duration of action. It is available as the hydrobromide salt. Homatropine is also given as an atropine substitute,[1] given to reverse the muscarinic and CNS effects associated with indirect cholinomimetic (anti-AChase) administration.

Homatropine hydrobromide is on the World Health Organization's List of Essential Medicines.[2]

Side effects edit

Contraindications edit

References edit

  1. ^ Scharer LL, Burhenne HJ (April 1964). "Megacolon associated with administration of an anticholinergic drug in a patient with ulcerative colitis". The American Journal of Digestive Diseases. 9 (4): 268–274. doi:10.1007/bf02232133. PMID 14142388. S2CID 19169565.
  2. ^ World Health Organization (2023). The selection and use of essential medicines 2023: web annex A: World Health Organization model list of essential medicines: 23rd list (2023). Geneva: World Health Organization. hdl:10665/371090. WHO/MHP/HPS/EML/2023.02.