Methylhomatropine

Homatropine methylbromide or 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. 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.