Antidiuretic effect of Sandostatin (SMS 201-995) in healthy volunteers

Ten male healthy volunteers were studied in order to determine whether the synthetic somatostatin analogue Sandostatin (SMS 201-995) has effects similar to those of natural somatostatin on renal water and electrolyte excretion. The study was carried out in three separate placebo-controlled randomized double-blind cross-over trials. The subjects received single sc injections of 100 micrograms Sandostatin and placebo under conditions of mild diuresis (trial 1), water load with enhanced diuresis (trial 2), and water load with exogenous lysin-vasopressin (5 IU sc) induced antidiuresis (trial 3). The following parameters were measured: urine flow rate, serum and urine osmolalities, osmolar clearance, free water and creatinine clearances, excretion rates of sodium, potassium, calcium, chloride, and phosphate, and immunoreactive insulin. A marked antidiuretic effect was observed within 2 h after dosing in all three trials. Urine flow rates were reduced by 45% in trial 1 and by 29 and 31% in trials 2 and 3, respectively (all P less than 0.05). There were no differences in effects on serum and urine osmolalities between Sandostatin and placebo. Osmolar clearance was significantly reduced in trial 1 (P less than 0.01). Free water clearance significantly decreased only in trial 2 (P less than 0.05). Sodium excretion decreased by 49, 48 and 67%, respectively, the differences being significant in trials 1 and 3 (P less than 0.05). Calcium excretion decreased by 66, 70 and 54% (all P less than 0.001). Chloride excretion decreased by 28, 22 and 44%, the differences being significant in trials 2 and 3 (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)