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Purpose: To assess the effect of tezosentan, a parenteral dual ET receptor antagonist, on splanchnic and systemic hemodynamics in patients with cirrhosis. In addition, the safety, pharmacokinetics, and pharmacodynamics of tezosentan were evaluated. Methods: The population consisted of patients with cirrhosis with clinically significant portal hypertension. This was a randomized, double-blind, multicenter study. The patients were randomized 3:1 to tezosentan (3 mg/h for 2-3 h) or placebo. HVPG, hepatic blood flow (HBF, ICG method), and systemic arterial pressures were measured before and after tezosentan administration. Plasma concentrations of tezosentan and ET-1 were determined peripherally and in the hepatic vein. Results: Eighteen patients received tezosentan and six placebo. Baseline clinical, biochemical, and hemodynamic characteristics were balanced between the two groups. There was no significant treatment effect on HVPG. The extraction ratio (0.31), the plasma clearance of ICG (280 ml/min), and the HBF (1,430 ml/min) did not show any relevant changes during the infusion of tezosentan, and there were no differences between placebo- and tezosentan-treated patients. A linear relationship was observed between the maximum-fold increase in ET-1 concentration and the steady-state tezosentan plasma concentration ( r = 0.82). There was a strong correlation ( r = 0.88) between plasma clearance of ICG and that of tezosentan (10.2 l/h). Arterial pressure and heart rate did not significantly change in either group. Conclusion: In patients with cirrhosis, a 2- to 3-h tezosentan infusion was safe and well tolerated but did not change the HVPG. Tezosentan infusion had no influence on the extraction ratio and plasma clearance of ICG and did not change HBF. [ABSTRACT FROM AUTHOR]

Objective. To investigate in 12 healthy subjects the pharmacokinetics and tolerability of tezosentan, an endothelin receptor antagonist, when given concomitantly with cyclosporin. Methods. Tezosentan was infused at a dose of 6.25 mg/h and 25 mg/h for 6 h either alone or following a single dose of 400 mg cyclosporin. Blood and urine samples were collected for pharmacokinetic determinations. Vital signs, electrocardiogram, adverse events, and clinical laboratory parameters were monitored to assess tolerability. Results. Concomitant cyclosporin resulted in a fourfold increase in the exposure to tezosentan. Tezosentan alone was well tolerated. In combination with cyclosporin, and at both doses, all subjects reported headache, hot flushes and nausea/vomiting, some of which were of severe intensity. Conclusion. The poor tolerability of the combination of cyclosporin and tezosentan is not correlated with the plasma concentrations of tezosentan. [ABSTRACT FROM AUTHOR]