DRUG-INDUCED BLADDER AND URINARY DISORDERS - INCIDENCE, PREVENTION AND MANAGEMENT

The bladder is vulnerable to the adverse effects of drugs because of i ts complex control and the frequent excretion of drug metabolites in t he urine, Incontinence results when bladder pressure exceeds sphincter resistance, Stress incontinence because of sphincter weakness occurs with antipsychotics and a-blockers, especially in women, Urge incontin ence and irritive symptoms may be caused by drugs. Anticholinergics, a naesthetics and analgesics cause urinary retention because of failure of bladder contraction. They are more likely to cause retention in men because of prostatic enlargement. Cyclophosphamide and tiaprofenic ac id can cause chemical cystitis, and should be withdrawn if a patient d evelops irritative symptoms or haematuria. Cyclophosphamide may also i nduce bladder tumours. Adverse effects of cyclophosphamide can be redu ced with prophylactic administration of mesna and adequate hydration. Mitomycin, doxorubicin or bacillus Calmette-Guerin (BCG) instilled loc ally to treat bladder tumours can cause cystitis, contracture and calc ification. Their administration should be limited to 1 hour per week f or a maximum of 8 weeks. Retroperitoneal fibrosis and urine discoloura tion may be caused by drugs. Ureteric calculi may result from any drug causing nephrolithiasis.