Diazepam Does Not Typically Cause Frequent Urination
Diazepam is associated with urinary retention and incontinence, not frequent urination, according to FDA labeling and clinical evidence. 1
FDA-Documented Urogenital Effects
The FDA drug label for diazepam specifically lists the following urogenital adverse effects 1:
- Incontinence (involuntary loss of urine)
- Urinary retention (inability to empty the bladder)
- Changes in libido
Notably, frequent urination (urinary frequency or polyuria) is not listed among diazepam's adverse effects. 1
Mechanism: Benzodiazepines Impair Bladder Emptying
Benzodiazepines like diazepam can cause urinary retention through their effects on bladder contraction 2:
- Benzodiazepines are documented to cause drug-induced urinary retention by impairing the micturition pathway 2
- In experimental studies, diazepam inhibited bladder contraction in anesthetized rats, though this effect was less pronounced in unanesthetized animals 3
- The mechanism involves interference with the complex neural control of bladder function 4, 2
Clinical Context: Retention vs. Frequency
It's important to distinguish between urinary retention and urinary frequency 5, 2:
Urinary retention (associated with diazepam):
- Impaired bladder emptying with increased post-void residual urine 2
- Can present as decreased urination, difficulty initiating urination, or overflow incontinence 2
Urinary frequency (NOT associated with diazepam):
- Increased number of voids (traditionally >7 during waking hours) 5
- Caused by conditions like overactive bladder, diabetes, heart failure, or urinary tract infections 5
- Requires evaluation with voiding diary, urinalysis, and post-void residual measurement 5
Risk Factors for Diazepam-Related Urinary Problems
Elderly patients are at higher risk for drug-induced urinary retention from benzodiazepines 2:
- Pre-existing benign prostatic hyperplasia in men increases risk 2
- Concomitant use of other anticholinergic medications potentiates the effect 2
- Falls and fractures are also more common in elderly benzodiazepine users 1
Clinical Recommendation
If a patient on diazepam reports frequent urination, look for alternative causes rather than attributing it to the medication 5:
- Perform urinalysis and urine culture to exclude infection 5
- Obtain a voiding diary documenting frequency, volumes, and fluid intake 5
- Measure post-void residual to identify overflow incontinence (which could paradoxically present as frequency) 5
- Consider systemic causes: diabetes, heart failure, or renal disease 5
The more likely diazepam-related urinary adverse effects are retention or incontinence, which should prompt dose reduction or discontinuation if problematic. 1, 2