Vasopressin Antagonists

VASOPRESSIN ANTAGONISTS

A group of nonpeptide antagonists of vasopressin receptors is being investigated for use in patients with hyponatremia or acute heart failure, which is often associated with elevated concentra-tions of vasopressin. Conivaptan has high affinity for both V_1a and V₂ receptors. Tolvaptan has a 30-fold higher affinity for V₂ than for V₁ receptors. In several clinical trials, both agents relieved symptoms and reduced objective signs of hyponatremia and heart failure. Conivaptan and tolvaptan are approved by the FDA for intravenous administration in hyponatremia. Several other nonse-lective nonpeptide vasopressin receptor antagonists are being investigated for these conditions .