Tolvapton is a/an -: (A) Angiotensin antagonist, (B) Renin inhibitor, (C) Vasopressin antagonist, (D) ACE inhibitor
Answer is C. Ans. is 'c' i.e., Vasopressin antagonist VAPTANSo A new class of medication, the "vaptan drugs", act by inhibiting the action of vasopressin on it receptors (V1A, V1B and V2) - Vasopressin receptor antagonists.# As already explained, V1 A receptors are involved in vasoconstriction - V1A antagonist can be used when total peripheral resistance is increased, e.g. in CHF and hypertension.# Example - Relcovaptan2) V1 B receptor antagonist# V1 B receptors are expressed in brain and pituitary gland - V1 B antagonist can be used as psychiatric drugs.# Example - Nelivaptan3) V2 receptor antagonists# 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 SIADH.# Examples - Lixivaptan, satavaptan, mozavaptan, Tolvaptan.4) Non-selective (mixed V1A/V2)# Can be used in CHF# Examples - Conivaptan