Pharmacokinetics and Haematological Effects of Desmopressin

The pharmacokinetics and haematological effects of 1-deamino-8-D-arginine vasopressin (desmopressin, DDAVP) after intravenous, subcutaneous and intranasal administration has been studied in man. Using a sensitive, specific radioimmunoassay for DDAVP, the AUC was determined for each route of administration. It was not significantly different for the i.v. and s.c. routes. There was no effect of the route on the plasma half-life of DDAVP which ranged from 2.7 to 4.6 h. Absorption of DDAVP after intranasal (i.n.) administration was poor. Based on AUC data, bioavailability via the two s.c. methods and the i.n. route was 112%, 94% and 2%, respectively. DDAVP has a pronounced effect on coagulation and fibrinolytic parameters, causing a 4.0- (i.v.), 2.9- (s.c.), 3.1- (s.c.; 40 micrograms/ml) and 1.2- (i.n.) fold increase in factor VIII: Ag. The corresponding effect on tissue-type plasminogen activator (t-PA) was 1.9- (i.v.), 1.3- (s.c.), 2.2- (s.c.; 40 micrograms/ml) and 1.0- (i.n.) increase over the basal value. There was also a 1.4- to 1.6-fold increase in leukocyte count 4 h after s.c. and i.v. DDAVP. At plasma DDAVP levels greater than 300 pg/ml no correlation was found between the AUC and the maximum plasma DDAVP and biological response, which indicates a ceiling limit for exogenous stimulation of the coagulation and fibrinolytic systems.