Homatropine methylbromide

Clinical data
Other names	Methylhomatropine bromide
ATC code	A03BB06 (WHO)
Identifiers
IUPAC name (N,N-Dimethyl-8-azoniabicyclo[3.2.1]oct-3-yl) 2-hydroxy-2-phenylacetate bromide
CAS Number	80-49-9
PubChem CID	6646
DrugBank	DB00725
ChemSpider	6394 Y
UNII	68JRS2HC1C
KEGG	D02070
ChEMBL	ChEMBL1200851
CompTox Dashboard (EPA)	DTXSID4023127
ECHA InfoCard	100.001.168
Chemical and physical data
Formula	C17H24BrNO3
Molar mass	370.287 g·mol−1
3D model (JSmol)	Interactive image
SMILES C[N+]1(C2CCC1CC(C2)OC(=O)C(C3=CC=CC=C3)O)C.[Br-]
InChI InChI=1S/C17H24NO3.BrH/c1-18(2)13-8-9-14(18)11-15(10-13)21-17(20)16(19)12-6-4-3-5-7-12;/h3-7,13-16,19H,8-11H2,1-2H3;1H/q+1;/p-1/t13-,14+,15+,16?; Y Key:ZTVIKZXZYLEVOL-MCOXGKPRSA-N Y
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Homatropine methylbromide (INN; also known as methylhomatropine bromide) is a quaternary ammonium salt of methylhomatropine. It is a peripherally acting anticholinergic medication that inhibits muscarinic acetylcholine receptors and thus the parasympathetic nervous system. It does not cross the blood–brain barrier. It is used to effectively relieve intestinal spasms and abdominal cramps, without producing the adverse effects of less specific anticholinergics.^[1] It is used, in addition to papaverine, as a component of mild drugs that help "flush" the bile.

Certain preparations of drugs such as hydrocodone are mixed with a small, sub-therapeutic amount of homatropine methylbromide to discourage intentional overdose.^[2]

Contraindications

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