DRUG-RELATED
Posted by admin on July 31st, 2010Nocturia is reported in 2h of women and men > 65 yr of age who are not taking drugs; for those who take drugs or have more than three chronic diseases, the incidence is > 80%. Nocturia contributes to sleep disturbance, a problem for > 20% of elderly persons (see Ch. 11).
Many older patients suffer from loss of bladder distensibi I ity and urinary concentrating ability. Therefore, if chronic diuretic therapy is required for hypertension or heart failure, two options should be considered: (I) For hypertension control, the smallest effective dose (eg, 12.5 or 25 mg hydrochlorothiazide) should be used once daily in the morning. (2) For treatment of heart failure, I h of recumbency in the morning after the dose of loop diuretic often obviates the need for twice-daily dosing. Excessive fluid intake or the use of “natural” diuretics (alcohol and caffeine) before bedtime should be avoided whenever nocturia is a significant problem.
The internal urinary sphincter is innervated in part by ?-adrenergic fibers. Thus, it is important in men with bladder outlet obstruction that this sphincter not be lightened by excess ?-adrenergic stimulation. Excessive sympathetic (u-adrcnergic) nervous system activity from sympathomimetics (eg, decongestants) can tighten the sphincter and lead to imbalance of the micturition reflex. On the other hand, ?-blocking agents, such as prazosin (prescribed for hypertension), may sometimes lead to incontinence because it reduces the tone of the sphincter.
The cholinergic system contracts the detrusor muscle. Thus, anticholinergic drugs, such as psychoactives, antidepressants, antihistamines, and certain antiarrhythmics, should be avoided to prevent weakening the contraction, which can lead to inadequate emptying
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