Agents for Urinary Incontinence and Urinary Analgesia

Chapter 34


Agents for Urinary Incontinence and Urinary Analgesia






INDICATIONS




• oxybutynin XL: dysuria, neurogenic bladder, overactive bladder, urge incontinence, frequency, urgency


• tolterodine LA: overactive bladder, urge incontinence, frequency, urgency


• trospium: treatment of overactive bladder with symptoms of urge urinary incontinence, urgency, and urinary frequency


• darifenacin: overactive bladder


• solifenacin: overactive bladder


• flavoxate: dysuria adjunct in urinary tract infection


• propantheline: adjunctive therapy for peptic ulcer


• desmopressin: primary nocturnal enuresis (intranasal)


• bethanechol: urinary retention


• phenazopyridine (Pyridium): dysuria


• Botox: Injection into bladder for those who lose bladder control because of damage to the nervous system due to conditions such as multiple sclerosis or spinal cord injury; not approved for PC tx overactive bladder yet



This chapter discusses genitourinary drugs used to treat urinary incontinence (UI), urinary retention, nocturnal enuresis in children, and urinary tract pain/discomfort. The condition discussed is UI, which occurs primarily in women and is not really a disease but a geriatric syndrome. Some of the drugs that are used to treat symptoms of UI have not been approved by the FDA for UI. For example, SNRIs are being studied for use in stress incontinence. The anticholinergics/antispasmodics, which are FDA approved for UI, are discussed in detail in this chapter. α-Adrenergic agonists, α-adrenergic antagonists, tricyclic antidepressants, sympathomimetics, and estrogens also are used, and information about those drugs may be found in the relevant chapters.


Desmopressin is a medication that is used in children with primary nocturnal enuresis. Phenazopyridine is used on a short-term basis for urinary analgesia, usually resulting from an acute UTI.



Therapeutic Overview


Urinary incontinence is the unintentional leakage of urine. Four basic types of established incontinence are known: stress, urge, mixed, and overflow.


Stress incontinence is leakage of urine that results from a reduction in urethral resistance and increased abdominal pressure associated with physical exertion (e.g., exercise, coughing, and sneezing). Causative factors include weak pelvic floor muscles, prostatectomy, and obesity. It is the most common type of incontinence in women younger than 60 years and also occurs in men who have had prostate surgery.


Urge incontinence, or overactive bladder, is caused by a hyperactive detrusor muscle and is associated with an intense urge to void before the bladder is full. Urge incontinence is associated with localized conditions (e.g., infection, atrophic vaginitis, stones, calculi, or other obstruction), neurologic disorders (e.g., CVA, Parkinson’s, Alzheimer’s), and metabolic conditions (e.g., diabetes, dehydration, vitamin B12 deficiency).


Overflow incontinence results from detrusor muscle underactivity and/or bladder outlet obstruction. Leakage of urine is small in volume and continual. Overflow incontinence is found in women with pelvic organ prolapse and in men with benign prostatic hyperplasia.


Urinary incontinence is a complex syndrome with multiple causes; it is not uncommon for individuals to experience more than one type.



Assessment


A focused history with a careful physical examination is essential for determining the cause of incontinence. Transient or reversible causes should be ruled out (Table 34-1). A bladder diary is a helpful diagnostic tool that reveals toileting habits, fluid intake, and leakage episodes. Urinalysis and postvoid residual are essential laboratory tests. Further evaluation by specialists may involve urodynamic and imaging tests.




Mechanism of Action


Anticholinergics


Anticholinergic drugs have many actions. They block muscarinic actions (a subset of the parasympathetic nervous system). Primary associated adverse effects are blurred vision, urinary retention, constipation, dry mouth, tachycardia, and confusion.


Anticholinergic medications used for urge incontinence include those in this chapter, tricyclic antidepressants (TCAs), and dicyclomine (Bentyl) (discussed in Chapter 29).


Anticholinergic drugs inhibit the action of acetylcholine on bladder smooth muscle. This blocks contraction of the bladder and decreases the urodynamic response of detrusor overactivity—the problem in urge incontinence. These actions result in increased bladder capacity, delayed desire to void, and diminished frequency of involuntary bladder contractions. Oxybutynin has both direct antispasmodic effects and anticholinergic effects on smooth muscle. Its direct relaxant effect on smooth muscle is produced by way of phosphodiesterase inhibition. The two newest drugs, darifenacin and solifenacin, have greater affinity for bladder smooth muscle cells than for salivary gland tissue. Darifenacin may have less affinity for the CNS receptors.








Treatment Principles


Standardized Guidelines





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Jul 22, 2016 | Posted by in PHARMACY | Comments Off on Agents for Urinary Incontinence and Urinary Analgesia

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