Leaky Bladder – Reasons for Poor Bladder Control and Drugs to Treat It

What is a Leaky Bladder?

Leaky bladder is the common term for urinary incontinence or enuresis. It is the term for any involuntary leakage of urine as the person is unable to prevent the flow of urine out of the bladder. It is often referred to simply as poor bladder control but urinary incontinence often involves other structures of the genitourinary system as well.

Drug therapy for incontinence may not be effective in every case. Depending on the cause and individual response to medication, drugs may only offer short term relief. Along with surgery, devices, behavioral and/or physical therapy, drugs may assist with the long term management of incontinence in both men and women.

Leaky Bladder in Different Age Groups

Incontinence in infants and toddlers as well as the elderly are a fairly common phenomenon and may occur for a host of reasons. It is not always due to a disease or disorder.

Children

Primary enuresis is the type of incontinence where a child has not as yet developed bladder control. Diurnal enuresis (daytime incontinence) should not be present in a child over the age of 5 years since most children develop bladder control (continence) when awake by this age. However, nighttime continence takes longer to develop. In a child younger than 6 years, nocturnal enuresis may not be considered as a problem unless it has suddenly started up in a child who has previously had good bladder control (secondary enuresis).

Elderly

In the elderly, age related changes in the urinary system can hamper bladder control and wetting may occur when sleeping or while awake without the person realizing that they have soiled themselves. Incontinence in the elderly (secondary enuresis) is more common in women and may be related to pelvic floor weakness caused by childbirth (postpartum) .

Incontinence in elderly men is often related to benign prostatic hyperplasia (enlarged prostate). Age related incontinence is not the norm and if it develops later in life, the cause should be investigated and appropriate treatment instituted. Incontinence in the elderly may be acute and transient and could pass with time and treatment.

Teens and Adults

Incontinence in preteens, teens and adults should always be investigated as it may be a sign of some underlying pathology. An overactive bladder (weak bladder) may lead to enuresis on some occasions in these age groups. Medication like diuretics that increase urination may aggravate a case of incontinence but are usually not the cause of poor bladder control.

Bladder Control for Passing Urine

Urine is stored in the bladder, a hollow muscular organ that receives urine from the kidneys via two ureters (one on either side). The muscles of the bladder wall are relaxed to allow urine to collect within it and the internal and external sphincter muscles ensure that urine from the bladder does not empty into the ureter.

These sphincter muscles remain contracted. When a person wants to voluntarily pass out urine (voiding), nerve signals cause the bladder muscles to contract thereby increasing the pressure and expelling the urine from the bladder. The sphincter muscles also relax to allow the urine to flow out into the ureter where it is then expelled into the environment.

There are two stages in the micturition cycle :

1. Storage where the bladder fills with urine. The detrusor muscle (bladder wall muscle) is relaxed during this stage and the sphincters remain contracted to prevent the passing of urine.
2. Voiding where urine is voluntarily passed out of the bladder, through the urethra and into the environment. During this stage the detrusor muscle contracts and increased pressure within the bladder while the sphincter muscles relax and allow urine to flow out.

Nerve supply to the bladder is as follows :

• Sympathetic stimulation (T10 to T12) causes relaxation of the detrusor muscle and contraction of the sphincter (closing).
• Parasympathetic stimulation (S2 to S4) causes contraction of the detrusor muscle and relaxation of the sphincter (opening).

Drugs for Incontinence

Anticholinergic Drugs

• Indication : Primarily used for urge incontinence and overactive bladder syndrome (unstable bladder).
• Action : Reduces contractility of the detrusor muscle (bladder wall). Muscarinic receptors are activated by acetylcholine (parasympathetic stimulation) released by the nerves innervating it. Receptor activation results in muscle contraction. Anticholinergic drugs block these muscarininc receptors thereby preventing acetylcholine from attaching to it and activating the muscle.
• Side Effects :
  Dryness of mucus membrane linings (mouth, nose, throat)
  Nausea
  Constipation
  Dizziness
  Headache
  Skin rashes
  Diminished sweating
  Palpitations
• Chemical Names :
  Oxybutynin
  Tolterodine
  Solifenacin
  Darifenacin
  Fesoterodine
  Trospium

Alpha-Adrenergic Agonist Drugs

• Indication : Stress incontinence
• Action : Improves muscle tone of sphincters. Sphincter muscles remain contracted due to sympathetic stimulation which prevents the outflow of urine. Bladder muscles, particularly the neck of the bladder, contain large amounts of receptors sensitive to alpha agonists. This causes muscle contraction and helps with urinary retention.
• Side Effects :
  Insomnia
  Anxiety
  Headache
  Difficulty breathing
  Sweating
• Chemical Names :
  Pseudoephedrine
  Phenylpropanolamine (recalled in the United States)

Tricyclic Antidepressants

• Indication : Urge, stress, mixed incontinence.
• Action : Helps to relax the detrusor muscle (bladder wall) and stimulate contraction of urethral sphincter muscle. May aggravate overflow incontinence.
• Side Effects :
  Dry mouth
  Nausea
  Fatigue
  Insomnia
  Blurred vision
  Dizziness
• Chemical Names :
  Imipramine
  Doxepin

Estrogen Replacement Therapy (Topical Estrogen)

• Indication : Post menopausal incontinence. Atrophic urethritis.
• Action : Improves blood supply and restores thickening of the wall of the urethra. Low level of estrogen results in thinning and reduced blood flow to the wall of the urethra. This decreases restriction to urine flow. Similar changes are seen in the vagina, bladder and labia.
• Side Effects :
  Nausea
  Breast tenderness
  Headache
  Mood swings
  Edema
• Chemical Names :
  Estradiol
  Dienestrol

Alpha-Blockers (Alpha Adrenergic Antagonists)

• Indication : Overflow incontinence caused by enlarged prostate and other causes of outlet obstruction.
• Action : Relaxes smooth muscle of the prostate and bladder neck. This muscle relaxation allows for the passage of urine out of bladder. This prevents excessive stretching of the bladder which can then lead to bladder muscle contractions.
• Side Effects :
  Nasal congestion
  Headache
  Hypotension (low blood pressure)
  Increased heart rate (tachycardia)
• Chemical Names :
  Terazosin
  Doxazosin
  Tamsulosin
  Alfzosin

Other Drugs

• Desmopression (antidiuretic) decreases urine production and is mainly used for bedwetting (nocturnal enuresis) in children.
• Duloxetine (serotonin-norepinephrine reputake inhibitor) increases urethral sphincter smooth muscle tone. Indicated for mixed incontinence (stress, urge).