True regarding Conivaptan is -: (A) Vasopressin Antagonist, (B) V2 selective action, (C) Given orally, (D) Used in the treatment of hypernatremia
Answer is A. Ans. is 'a' i.e., Vasopressin Antagonist ADH (Vasopressin) receptors VtaV1b (also called V3) o Release of vWF & Factor VIIIo Blood vessels - vasoconstrictiono Anterior pitutary -from endotheliumo Visceral smooth muscle - contractionrelease of ACTH o Liver - glycogenolysis o Platelet - aggregation o V receptors are more sensitive to ADH than V, receptors.VAPTANSo A new class of medication, the "vaptan drugs", act by inhibiting the action of vasopressin on it receptors (VIA, V1B and V2) ?Vasopressin receptor antagonists.VIA receptor antagonisto As already explained, V1 A receptors are involved in vasoconstriction ? V1 A antagonist can be used when total peripheral resistance is increased, e.g. in CHF and hypertension.Example - RelcovaptanVI B receptor antagonisto VI B receptors are expressed in brain and pituitary gland ? VI B antagonist can be used as psychiatric drugs.Example - NelivaptanV2 receptor antagonistso V2 receptors are mainly responsible for increase water permeability in kidney ? V2 antagonists can be used when there is excessive ADH induced fluid retention as in SI ADH.Examples - Lixivaptan.satavaptan, mozavaptan, Tolvaptano Tolvaptan is currently the only oral V2 antagonist approved by the U.S. FDA.Non-selective (mixed V1A/V2)o Can be used in CHF (hypervolemic hyponatremia)Examples -Conivaptan