1-Deamino-8-D-arginine vasopressin (DDAVP, desmopressin), a synthetic analog of the antidiuretic hormone L-arginine vasopressin, improves hemostasis parameters in cirrhotic patients. Hence its use in combination with a vasoactive drug such as terlipressin might improve the performance of this drug in controlling variceal bleeding. The aim of this trial was to compare the efficacy of desmopressin plus terlipressin with that of terlipressin alone in controlling acute variceal hemorrhage. Cirrhotic patients with active variceal hemorrhage diagnosed endoscopically were randomized within 2 hr of admission to receive desmopressin plus terlipressin or placebo plus terlipressin. Terlipressin (2 mg, intravenous bolus) was given at time 0 and every 4 hr thereafter for 24 hr. Desmopressin (0.3 microgram/kg, intravenously) or placebo was given in saline solution over 30 min at time 0 and at 26 hr. Patients were monitored for 24 hr after cessation of treatment. Treatment failure was defined as recurrence of active bleeding during treatment or within the 24 hr after treatment. After enrolling 51 of the planned 84 patients, we carried out an interim analysis. Treatment failure occurred in 13 of 24 patients randomized to receive desmopressin plus terlipressin (54.2%) and in 6 of 22 patients randomized to receive terlipressin (27.3%) (p = 0.06, Fisher's exact test). The trial was interrupted at this stage because patients treated with the "new" therapy fared worse than those treated with the standard therapy, and the possibility of reversing this trend by completing the trial was deemed remote. The addition of desmopressin does not improve and may worsen the efficacy of terlipressin in controlling acute variceal bleeding in cirrhotic patients.