• Anticholinergic

      • Muscarinic Antagonist


    • frequent urination


    • Oral

      • Rapidly absorbed from gastrointestinal tract



    • 91-93% protein bound

    • VOD 193 L


    • competitively antagonizes the M1, M2, and M3 subtypes of the muscarinic acetylcholine receptor

      • exerts a direct antispasmodic effect on smooth muscle

      • inhibits the muscarinic action of acetylcholine on smooth muscle

    • No blocking effects occur at skeletal neuromuscular junctions or autonomic ganglia (antinicotinic effects)

    • By inhibiting particularily the M1 and M2 receptors of the bladder, detrusor activity is markedly decreased


    • metabolized primarily by the cytochrome P450 enzyme systems

      • particularly CYP3A4

      • found mostly in the liver and gut wall

    • Extensively metabolized by the liver, with less than 0.1% of the administered dose excreted unchanged in the urine

Side effects

    • dry mouth

      • over a quarter of patients who begin oxybutynin treatment may have to stop because of dry mouth

    • difficulty in urination

    • constipation

    • blurred vision

    • drowsiness and dizziness

    • Calcium defects

      • An intake of calcium of 800 to 1000 mg is suggested



    • untreated angle closure glaucoma

    • untreated narrow anterior chamber angles

    • partial or complete obstruction of the gastrointestinal tract

    • hiatal hernia

  • gastroesophageal reflux disease

    • paralytic ileus

    • intestinal atony of the elderly or debilitated patient

    • toxic megacolon complicating ulcerative colitis

    • severe colitis

    • myasthenia gravis