Desmopressin in nocturnal enuresis. The effect of intranasal desmopressin on primary nocturnal enuresis was investigated in a study divided into 2 parts in which the first part was a randomized, double-blind, placebo-controlled cross-over study of 52 Finnish school children 5 to 13 years old. A variety of approaches had previously been attempted in most children, including water deprivation, night awakenings, enuresis alarm and imipramine, without success. The patients were randomized to 4 periods of 3 weeks each: 2 periods on placebo and 2 periods on 20 micrograms. desmopressin spray. The entire 12-week treatment period was preceded and followed by control periods (without treatment). The number of dry nights, measured as calculated averages per week, increased significantly (p less than 0.01) from 0.6 dry nights during pre-treatment to 4.3 and 4.6 dry nights per week during the 2 desmopressin treatment periods, respectively. The placebo responses were 2.1 and 2.4 dry nights per week, respectively. The second part of the study was an open dose-finding and drug safety study of a further 3 months in duration. The aim was to evaluate the efficacy and tolerance of 20, 30 and 40 micrograms. doses. All 47 patients who relapsed during the post-treatment period in part 1 were included. During this period 53% of the patients responded fully, 19% were intermediate responders and 28% did not respond. As reported in other studies most patients suffered relapse after treatment. During continued treatment for 3 months at doses between 20 and 40 micrograms. desmopressin was well tolerated, had no effect on body weight or blood pressure and did not cause any adverse reactions. 