Tolvaptan: Vasopressin Antagonist

Tolvaptan is vasopressin antagonist which acts on the V2 receptors in the renal tubules. Activation of V2 receptors increases water permeability in the renal collecting duct resulting in passive reabsorption of water. This causes aquaresis or free water clearance. Syndrome of inappropriate anti-diuretic hormone secretion (SIADH), heart failure and cirrhosis can be associated with increased secretion of arginine vasopressin (AVP). This leads to water retention or inadequate water excretion and hyponatremia (dilutional hyponatremia). Tolvaptan binds to V2 receptors and induces excretion of electrolyte-free water without altering the electrolyte excretion. Tolvaptan: Indications Tolvaptan is indicated for the treatment of hypervolemic and euvolemic hyponatremia, with serum sodium <125 mEq/L or less marked hyponatremia that is symptomatic and has resisted correction with fluid restriction. Such situations occur with heart failure, cirrhosis, and SIADH. Tolvaptan – Adverse Effects As expected from its therapeutic action, important adverse effects of tolvaptan are increased thirst, dryness of mouth, increased urination and sometime dehydration leading to hypotension and syncope. Gastrointestinal hemorrhage may occur in those with cirrhosis liver. Hypernatremia and hyperkalemia are potential problems and very rarely osmotic demyelination is possible due to rapid correction of hyponatremia. Tolvaptan – Contraindications Tolvaptan is not the treatment when there is an urgent...
Source: Cardiophile MD - Category: Cardiology Authors: Tags: General Source Type: blogs