Therapeutic: urinary tract antispasmodics
Treatment of overactive bladder function that results in urinary frequency, urgency, or urge incontinence.
Acts as a competitive muscarinic receptor antagonist resulting in inhibition of cholinergically mediated bladder contraction. Therapeutic Effects: Decreased urinary frequency, urgency, and urge incontinence.
Adverse Reactions/Side Effects
CV: tachycardia (dose related). GI: dry mouth, constipation, nausea, upper abdominal pain. GU: dysuria, urinary retention. MS: back pain.
PHYSICAL THERAPY IMPLICATIONS
Examination and Evaluation
Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Report an increased heart rate (tachycardia) or symptoms of other arrhythmias, including palpitations, chest discomfort, shortness of breath, fainting, and fatigue/weakness.
Monitor signs of urine retention (difficult urination, painful or distended abdomen). Excessive urinary retention may require dose adjustment by physician.
Assess any back pain to rule out musculoskeletal pathology; that is, try to determine if pain is drug induced rather than caused by anatomic or biomechanical problems.
Advise patient to increase fluid intake and dietary fiber to avoid constipation. Laxatives may also be helpful in patients susceptible to fecal impaction.
Instruct patient and family/caregivers to report other troublesome side effects such as severe or prolonged headache, blurred vision, dry eyes, or GI problems (nausea, dry mouth, abdominal pain).
Absorption: Rapidly absorbed following oral administration, but is rapidly converted to its active metabolite (bioavailability of metabolite 52%; further metabolism occurs in the liver via CYP2D6 and CYP3A4 enzyme systems. 16% of active metabolite is excreted in urine, most of the remainder of inactive metabolites are renally excreted. 7% excreted in feces.
Metabolism and Excretion: Rapidly converted by esterases to active metabolite.
Half-life: 7 hr (following oral administration).
Contraindicated in: Hypersensitivity; Urinary retention; Gastric retention; Severe hepatic impairment; Uncontrolled narrow-angle glaucoma.
Use Cautiously in: Significant bladder outlet obstruction (↑ risk of retention); Severe renal insufficiency (dose adjustment required); Decreased GI motility, including severe constipation; Treated narrow-angle glaucoma (use only if benefits outweigh risks); Myasthenia gravis; Severe renal impairment (dose should not exceed 4 mg/day); Geri: ↑ risk of anticholinergic side effects in patients >75 yr; OB/Lactation: Avoid using unless potential benefits outweighs potential risk to fetus/neonate; Pedi: Safety in children not established.