What is the role of anticholinergic agents in urinary incontinence treatment?

Updated: Mar 19, 2019
  • Author: Sandip P Vasavada, MD; Chief Editor: Edward David Kim, MD, FACS  more...
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Answer

The clinical and urodynamic effects of blocking cholinergic receptors in the bladder are as follows:

  • Increased bladder capacity
  • Increased volume threshold for initiation of an involuntary contraction
  • Decreased strength of involuntary contractions

Propantheline bromide is an anticholinergic agent that has been used to treat detrusor overactivity. Propantheline commonly is prescribed in dosages of 15-30 mg every 4-6 hours. In one study, propantheline bromide decreased the rate of urge incontinence by 13-17% when 30 mg were used qid. When higher doses were used, 60 mg qid, the cure rate was reported to be over 90%. Because gastrointestinal absorption is poor, it is often recommended that propantheline be taken on an empty stomach.

Typical anticholinergic adverse effects can be expected, including dry mouth, constipation, dry eyes, blurred vision, orthostatic hypotension, and increased heart rate. This agent probably should be avoided by patients with heart disease and closed-angle glaucoma. Improvement rates in various studies generally have been approximately 50%. Propantheline is no longer considered a first-line drug for detrusor instability due to relatively poor efficacy and a high incidence of adverse effects.

Oxybutynin (Ditropan XL), which has both antimuscarinic and antispasmodic effects, reduces incontinence episodes by 83-90%. The total continence rate has been reported to be 41-50%. Mean reduction in urinary frequency was 23%. In clinical trials, only 1% stopped taking the drug because of dry mouth and less than 1% stopped taking it due to CNS adverse effects.

Tolterodine (Detrol) is a potent antimuscarinic agent for treating detrusor overactivity. In animal models, the drug has shown selectivity for the urinary tract over the salivary glands. Tolterodine has performed well in clinical trials, showing comparable efficacy to oxybutynin with lower discontinuance rates. The dosage range is 1-2 mg twice daily.

In clinical studies, the mean decrease in urge incontinence episodes was 50% and the mean decrease in urinary frequency was 17%. The mean decrease in urge incontinence episodes per week was 53% for long-acting tolterodine (Detrol LA) 4 mg qd.

In the Overactive Bladder: Judging Effective Control and Treatment (OBJECT) trial, extended-release oxybutynin 10 mg was statistically superior to tolterodine 2 mg bid in controlling urge incontinence, total incontinence, and micturition frequency. Both drugs had similar adverse-effect profiles. [66] OBJECT was a large double-blind, multicenter, prospective, randomized controlled study in 276 women and 56 men with symptoms of overactive bladder.

Two small studies examining the use of transdermal scopolamine in the treatment of detrusor overactivity have been reported. The results of these studies are conflicting in terms of both efficacy and tolerability of adverse effects.

Trospium (Sanctura) elicits antispasmodic and antimuscarinic effects. It acts by antagonizing acetylcholine effect on muscarinic receptors. Parasympathetic effect reduces smooth muscle tone in the bladder.

Trospium is indicated to treat urinary incontinence, urgency, and frequency. The typical dosage is 20 mg bid taken on an empty stomach at least 1 h before meals. The dose is reduced to 20 mg hs in patients with renal insufficiency (ie, creatinine clearance [CrCl] < 30 mL/min). Elderly individuals (ie, > 75 y) may require a similar dose reduction to avoid adverse effects. Mild anticholinergic effects (eg, dry mouth, constipation, dry eyes, blurred vision) may occur.

Solifenacin (VESIcare) is a competitive muscarinic receptor antagonist that causes anticholinergic effects and inhibits bladder smooth muscle contraction. The initial dosage is 5 mg qd, which may be increased to 10 mg/d if tolerated and warranted. [67] The tablet must be swallowed whole (not crushed) with liquid.


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