← Search & browse all drugs

homatropine methylbromide

A03BB06

Forms & Strengths

Tablet: 5 mg
Combination products (e.g., with hydrocodone): various strengths

Adult Dosing

Gastrointestinal disorders: 2.5 to 5 mg orally up to four times daily before meals
Maximum daily dose: 30 mg

Pediatric Dosing

Safety and efficacy not well established in pediatric patients
Use generally not recommended or requires individualized expert dosing

Indications

Adjunctive therapy in the treatment of peptic ulcer disease
Management of irritable bowel syndrome and other functional gastrointestinal disorders characterized by hypermotility

Mechanism of Action

Competitive antagonist at muscarinic acetylcholine receptors (anticholinergic/antispasmodic)
Relaxes smooth muscle tone and decreases GI secretions by inhibiting parasympathetic nerve impulses
Quaternary ammonium compound with limited penetration across the blood-brain barrier

Contraindications

Glaucoma (narrow-angle)
Obstructive uropathy (e.g., bladder neck obstruction due to prostatic hypertrophy)
Obstructive disease of the gastrointestinal tract (e.g., achalasia, pyloroduodenal stenosis)
Paralytic ileus, intestinal atony, or severe ulcerative colitis
Myasthenia gravis
Known hypersensitivity to homatropine or anticholinergics

Adverse Reactions

Xerostomia (dry mouth)
Blurred vision and cycloplegia
Constipation and urinary retention
Tachycardia and palpitations
Drowsiness, dizziness, and headache
Flushed, dry skin and reduced sweating (anhidrosis)

Drug Interactions

Amantadine, antiparkinsonism drugs, and other anticholinergics: enhanced anticholinergic adverse effects
Phenothiazines, tricyclic antidepressants: additive antimuscarinic toxicity
Digoxin: increased serum concentrations due to decreased GI motility
Metoclopramide: antagonism of GI prokinetic effects

Curated Content: Needs Vetting Before Put to Clinical Use