Chemotherapy Induced Nausea and Vomiting (CINV) the most common side effect of chemotherapy is associated with a significant deterioration in quality of life  and is perceived by patients as a major adverse effect of treatment.

Chemotherapy is a common modality for treatment of Carcinoma Breast. Regardless of the fact that chemotherapy improves survival, it has its own toxicity and side effects of which nausea and vomiting being significant can affect patient compliance. To avoid the clinical sequelae of CINV like dehydration, electrolyte imbalance, malnutrition, anorexia, stress and anxiety, it is imperative to provide prophylaxis and treatment for CINV. 

The principal neurotransmitters that drive CINV in all forms are serotonin, dopamine, acetylcholine, and substance P.  The use of 5-hydroxytryptamine₃ (5-HT₃) receptor antagonist plus dexamethasone has significantly improved the control of acute CINV.  Recent studies have demonstrated additional improvement in the control of acute CINV and delayed CINV with the use of newer agents: Palonosetron, a second generation 5-HT₃ receptor antagonist.  Aprepitant, the first agent available in the drug class of neurokinin-1 (NK₁)-receptor antagonists and Olanzapine, an antipsychotic which is used in the treatment of psychotic symptom, blocks multiple neurotransmitters in the central nervous system.  These newer drugs incorporated in prophylactic regimens for CINV have resulted in significantly reduced rates of this feared complication of cytotoxic chemotherapy. A recent randomized trial evidence has suggested that Olanzapine may have a role in both the prevention and treatment of CINV.