1. Dosage

Current therapies for chemotherapy-induced nausea/vomiting (CINV) and post-operative nausea and vomiting (PONV) target corticosteroid, dopamine, and serotonin (5-HT3) receptors. In the central nervous system, tachykinins and neurokinins play a role in some autonomic reflexes and behaviors. Substance P and NK1 receptors control the emetic reflex, and substance P increases contractions of smooth gastrointestinal muscles leading to vasodilation¹. Aprepitant is a selective human substance P/neurokinin 1 (NK1) antagonist with a high affinity for NK1 receptors and little, if any, attraction for corticosteroid, dopamine, or 5-HT3 receptors^1-5. Rolapitant (Varubi®) is a selective, competitive antagonist of substance P/NK1 receptors, and it has little to no affinity for NK2 or NK3 receptors^1,2,6. Combination therapy including netupitant, a substance P/NK1 antagonist and palonosetron, a selective 5-HT3 receptor antagonist (Akynzeo®), is also available. Palonosetron targets CINV in the acute phase while netupitant prevents CINV in both the acute and delayed phases^1,2,7.