Homatropine

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.com	Monograph
MedlinePlus	a601006
ATC code	S01FA05 (WHO)
Legal status
Legal status	In general: ℞ (Prescription only)
Identifiers
IUPAC name (N-Methyl-8-azabicyclo[3.2.1]oct-3-yl) 2-hydroxy-2-phenylacetate
CAS Number	87-00-3 N
PubChem CID	6321423
DrugBank	DB00725 N
ChemSpider	16498795 Y
UNII	8QS6WCL55Z
ChEMBL	ChEMBL1233442 N
CompTox Dashboard (EPA)	DTXSID6044014
ECHA InfoCard	100.001.561
Chemical and physical data
Formula	C16H21NO3
Molar mass	275.348 g·mol−1
3D model (JSmol)	Interactive image
SMILES CN3[C@H]1CC[C@@H]3C[C@@H](C1)OC(=O)C(O)c2ccccc2
InChI 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? Y Key:ZTVIKZXZYLEVOL-MCOXGKPRSA-N Y
NY (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]

It is an antagonist of all five muscarinic acetylcholine receptors.^[3]

Side effects

• Blurred vision
• Sensitivity to light

Contraindications

• Untreated glaucoma
• Myasthenia gravis
• Severe heart failure
• Thyrotoxicosis