Drug-induced urinary retention: incidence, management and prevention.

Urinary retention is a condition in which impaired emptying of the bladder results in postvoidal residual urine. It is generally classified into 'acute' or 'chronic' urinary retention. Because of the complex mechanism of micturition, many drugs can interact with the micturition pathway, all via different modes of action. Although the incidence of urinary retention, in particular acute urinary retention, has been well studied in observational studies and randomized controlled trials, data on the incidence of drug-induced urinary retention are scarce. Data from observational studies suggest that up to 10% of episodes might be attributable to the use of concomitant medication. Urinary retention has been described with the use of drugs with anticholinergic activity (e.g. antipsychotic drugs, antidepressant agents and anticholinergic respiratory agents), opioids and anaesthetics, alpha-adrenoceptor agonists, benzodiazepines, NSAIDs, detrusor relaxants and calcium channel antagonists. Elderly patients are at higher risk for developing drug-induced urinary retention, because of existing co-morbidities such as benign prostatic hyperplasia and the use of other concomitant medication that could reinforce the impairing effect on micturition. Drug-induced urinary retention is generally treated by urinary catheterization, especially if acute, in combination with discontinuation or a reduction in dose of the causal drug. Studies have been carried out examining the effects of preventive measures for anaesthesia-related urinary retention, both during and after surgery, particularly into the effect of using opioids in combination with non-opioid analgesic drugs on the incidence of postoperative urinary retention. Although combination therapy reduces the opioid-related adverse events, the effect on urinary retention yields contradictory results. This article reviews the literature on drug-induced urinary retention and focuses on its incidence, the different classes of drugs that have been associated with it, and options for its management and prevention.