Desmopressin in the treatment of daytime urinary frequency in patients with multiple sclerosis.

Twenty two patients with multiple sclerosis, complaining of frequency of day time micturition, completed a double blind crossover trial of desmopressin (DDAVP nasal spray) versus placebo. There was a significant decrease in micturition frequency in the 6 hour post-treatment period from 3.1 voids after placebo to 2.4 voids and a significant reduction in urinary volume after desmopressin. Eighty per cent of patients preferred the active treatment phase. Mean 24 hour urinary volume did not differ between active and placebo treatments and patients did not complain of increased night time frequency. Transient symptoms of hyponatraemia occurred in one patient but these resolved within 48 hours of stopping desmopressin. There were otherwise no side effects and mean serum sodium concentrations of the group remained unchanged throughout the study. The clinical indications for prescribing daytime desmopressin are discussed and the importance of patient compliance stressed.