ANTIDIURETIC EFFECT OF DESMOPRESSIN GIVEN IN HEMOSTATIC DOSAGES TO HEALTHY-VOLUNTEERS

The aim of this study was to characterize the magnitude and duration o f the antidiuretic effects elicited by desmopressin given in hemostati c dosage intravenously (i.v.) (0.3 mu g/kg) or intranasally (i.n.) (30 0 mu g) both as single or repeated doses (four i.n. doses with 12-hr i ntervals) to healthy volunteers.Urine osmolality increased to a maximu m median value of 1,087 mOsmol/kg after the single i.v. dose, 1,065 af ter the single i.n. dose, and 1,071 during the repeated i.n. dosing sc hedule, and did not differ significantly between the three dosage sche dules. The increase lasted for 24 hr after single doses, and 12 hr aft er the last of the repeated i.n. doses. Serum sodium did not decrease more than normal diurnal variation after single doses, but decreased m arginally below the normal reference range in three volunteers after r epeated doses. Lowest median serum sodium concentrations after single i.v. and i.n. doses were 140 and 141 mmol/l, respectively, and 139 aft er repeated i.n. doses. Body weight changed only marginally after sing le doses, but increased 1.3 kg during repeated dosing. In adult health y volunteers, single desmopressin doses give an antidiuretic effect la sting for about 24 hr. There is no difference in magnitude or duration between i.v. or i.n. doses. The effect is prolonged as long as the do ses are repeated. Serum sodium is only marginally affected by single d oses, but tends to decrease after four repeated doses with 12-hr inter vals. If desmopressin is repeated for a period of up to 48 hr, fluid i ntake should be restricted to 2 liters per day in adults. (C) 1998 Wil ey-Liss, Inc.