Desmopressin (DDAVP), a synthetic analogue of vasopressin, has been shown to improve the bleeding time in patients with cirrhosis. The duration of this effect and the hemodynamic changes associated with DDAVP have not been studied so far. To evaluate these issues, 14 cirrhotics with portal hypertension were studied in basal conditions and after DDAVP (0.3 uk/kg). In 8 patients, hemostatic tests were done at basal conditions and 1, 3, 6 and 24 hs after drug administration. In the remaining 6 patients, mean arterial pressure, cardiac output, portal and femoral blood flows were evaluated. Hemodynamic parameters were measured by Doppler ultrasound. DDVP caused a marked decrease in bleeding time at 1, 3, 6 and 24 hs (14 +/- 9 vs 8 +/- 3, 7 +/- 4, 6 +/- 4 and 8 +/- 4 min, respectively); the decrease was maximal and statistically significant at 6 hs (55 +/- 15%, p < 0.02) after DDAVP infusion. Bleeding time reduction was observed in every patient studied. In the hemodynamic study, DDAVP caused a mild but significant decrease in mean arterial pressure (12 +/- 8%, p < 0.05); no significant changes were observed in the rest of hemodynamic parameters studied. These findings show that DDAVP can be used to shorten the bleeding time for a period of at least 24 hs in patients with cirrhosis, without deleterious hemodynamic effects. This beneficial effect may be of potential relevance in the medical management of patients with chronic liver diseases.