This study also found that the use of alpha blockers increased the risk of urinary
incontinence in older black and white women by nearly five fold. This finding corroborates
work by Marshall et al. who reported that 20 of 49 (40.8%) women taking an alpha blocker
(prazosin, terazosin, and doxazosin) had urinary incontinence.24 This adverse effect was
confirmed by dechallenge where withdrawal of the drug from 17 patients reduced the
number of patients with incontinence to 6 (14%). In a follow-up analysis that controlled for
potential confounders, this same group of investigators found a nearly two fold increased
risk of urinary incontinence with the use of α-blockers.12 It is biologically plausible that
alpha blockers can increase the risk of urinary incontinence in women because its use can
cause urethral relaxation. This may be particularly problematic in older women since
urethral length and sphincter strength both decline with age in older women 3 and alpha
adrenergic tone may be the last barrier to stress urinary incontinence. Given this data, the
high risk of orthostatic hypotension associated with the use of these agents in older adults
and the results from ALLHAT study which disclosed an increased hospitalization rate for
heart failure among users of doxazosin, other approaches should be preferred for the
treatment of hypertension in elderly women.25