A Treatment for Getting Up at Night

Summarized by Robert W. Griffith, MD
November 4, 2002 (Reviewed: November 13, 2004)

Introduction

As we get older, many of us find we have to get up at night to pass urine - sometimes more than once. This problem doesn't occur just in men, although they are more likely to report it. Often an enlarged prostate gland is blamed, incorrectly. Women have the same trouble, but they're less likely to complain about it.

Apart from the nuisance value, having to get up to make a trip to the bathroom carries a risk of falling, at least in older people. Poor night vision, low blood pressure on standing, and the use of medications that cause drowsiness or dizziness all contribute to an increased risk of falling. And falls themselves can lead to fractures of the hip or wrist, with the possible need for hospitalization.

Why do we have to get up more at night than we did in our youth? The cause is the loss of the rhythmic secretion of a hormone that regulates the manufacture of urine by the kidneys. Restoration of this rhythm might provide not only a better night's sleep, but also a real benefit in terms of reduced falls at night.

Scandinavian scientists have studied the effect of desmopressin, an orally active relative of the defective hormone (arginine vasopressin), in older people with the need to get up at night to urinate.

How the study was done

Men were enrolled if they had to urinate twice or more after going to bed, and their urine output at night was above a certain amount. Also, they had to have no other possible cause for increased nighttime urination.

In a first phase, increasing doses of desmopressin were given, to see what was the best dose for the participants to use in the main study. Doses given were 0.1, then 0.2, and finally 0.4 mg of desmopressin, given by mouth at bedtime. The purpose was to find the lowest effective dose, i.e. one that would reduce the amount of urine passed at night by 20% or more without unpleasant side effects. Those volunteers who obtained such a reduction with one of the doses of desmopressin were considered to be 'responders'.

Responders were then randomly allocated to take either desmopressin (at their particular chosen dose) or placebo, for three weeks. During this time they had clinical and lab tests, and kept a diary recording their 24-hour fluid intake, and the time and volume of their urination at night.

What the study found

There were 151 responders among the 224 who enrolled in the responder-finding phase - about 2 out of 3. Of those who dropped out during this first phase, about 1 in 5 did so because there was no response to the medication, and another 1 in 5 withdrew because of side effects of the drug.

The average age of the participants was 65. On average they got up 3.1 times to urinate at night. Treatment with desmopressin reduced this number by at least half in 34% of those taking the drug, compared with a placebo effect of only 3%. Overall, the average number of times was reduced with desmopressin from 3.0 per night to 1.7 per night.

The average time to the first need to get up was 2.6 hours at baseline. Desmopressin treatment increased this to 4.5 hours, while placebo increased it to 2.9 hours.

Similar numbers of patients from each group reported side events: 17% in the desmopressin and 25% in the placebo group. The majority of these were mild - mostly headache. Five patients had more serious adverse events, but none was judged to be related to desmopressin or placebo - i.e. they were coincidental.

Comment

The results of this study show that replacing a defective hormone can partially restore the normal rhythm of urine formation, and thus lessen the need to urinate at night. The risk of falls in older persons getting out of bed at night that we referred to earlier has been well documented. Perhaps a pill at bedtime will provide a way of avoiding those perilous trips to the bathroom that is more acceptable than grandfather's way -- the chamber-pot under the bed.

Source

• Efficacy of desmopressin in the treatment of nocturia: a double-blind placebo-controlled study in men. A. Mattiasson, P. Abrams, P. Van Kerrebroeck,  et al., Brit J Urol Intern, 2002, vol. 89, pp. 855--862

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