Medical Edge Newspaper Column

Diuretics and Overactive Bladder

March 6, 2006
DEAR MAYO CLINIC:
My sister-in-law takes hydrochlorothiazide, a diuretic, for blood-pressure control. Now her doctor wants to prescribe Detrol LA [tolterodine tartrate] for her overactive bladder. Is this combination safe? Wouldn't the new medication try to undo what the diuretic is doing? -- Plainfield, Ill.

ANSWER:
The combination you describe is safe, effective and not uncommon.

Hydrochlorothiazide and other diuretics (sometimes called water pills) help control blood pressure by making the kidneys excrete more sodium in urine. The sodium takes water with it from the blood, which decreases the amount of fluid flowing through the blood vessels, reducing pressure on the arteries' walls.

The diuretic is commonly taken in the morning. As the bladder fills repeatedly for four to six hours afterward, the patient needs to make more frequent trips to the bathroom. It is important for the medical provider to know what other drugs a patient is taking. Many -- such as analgesics, sleep medications and antidepressants -- can also affect bladder function.

Assuming that other drugs are not complicating matters, your sister-in-law has urinary frequency from two sources -- her diuretic and an overactive bladder (OAB) -- which are treated separately. OAB resulting from involuntary contractions of the bladder not only can increase frequency of urination but can cause urinary urgency and urinary-urge incontinence. It affects men and women alike, especially as they age.

Integral to OAB treatment is behavior modification: bladder retraining, timed voiding, fluid management, and the avoidance of caffeine and other bladder irritants -- such as citrus juices. Another approach is to use anticholinergics (anti-spasm drugs), including the Detrol LA you mention. These medications are meant to reduce involuntary bladder contractions, which typically occur throughout the day and night.

If your sister-in-law has symptoms suggestive of OAB, the Detrol LA or other anticholinergic medications may help. And because their only purpose is to reduce involuntary bladder contractions, they will not counteract or interfere with her diuretic. Therefore hydrochlorothiazide and Detrol LA are safe to use together.

-- John B. Gebhart, M.D., Urinary Continence Clinic, Mayo Clinic, Rochester, Minn.