Drug-Induced Urinary Incontinence

Physiological urinary continence depends on many factors that are potentially vulnerable to adverse drug effects, which may lead to incontinence. In principle, drugs could cause incontinence by lowering bladder outlet resistance and/or by increasing intravesical pressure, which disrupts the normal pressure relationship between the bladder and urethra and leads to urinary leakage; other possibilities include disturbances of central nervous control of voiding or an overproduction of urine. While many drug groups could theoretically induce urinary incontinence based upon pathophysiological considerations, evidence demonstrating a cause-effect relationship between drug usage and incontinence is sparse. Drug classes in which induction of incontinence has been proposed include α₁-adrenoceptor antagonists, antipsychotics, benzodiazepines, antidepressants and hormone replacement therapy in postmenopausal women. However, other drug classes are not innocent in terms of causing urinary incontinence and physicians are well advised to closely monitor patients for the occurrence of incontinence after new prescriptions and/or major dosage changes.