Cases: Second-Line Anti-emetic Therapies for Refractory Chemotherapy-Induced Nausea and Vomiting (CINV)

Discussion:Nausea and vomiting (NV) are commonly reported side effects with chemotherapy.1 The primary pathway for NV involves the chemotherapy drugs directly stimulating the chemoreceptor trigger zone (CTZ), in the area postrema at the base of the fourth ventricle. Activated receptors in the CTZ transmit signals to the vomiting center in the brainstem to produce NV. Receptors in the CTZ include serotonergic receptor 5-hydroxytryptamine type 3 (5-HT3), dopaminergic (D2) and neurokinin type 1 (NK-1) receptors. In addition, chemotherapy can damage GI mucosa causing local release of 5-HT3 neurotransmitters by gut enterochromaffin cells, activating peripheral pathways along the vagus and splanchnic nerves and directly triggering the vomiting center. Finally, chemotherapy-associated anxiety may also stimulate the vomiting center through central cortical pathways. Whether transmitted via signals from the CTZ, the cortex, or peripheral inputs, the vomiting center has several different receptors involved in initiating the vomiting reflex: muscarinic acetylcholine (Achm), histamine type 1 (H1), and 5-hydroxytrypamine type 2 (5-HT2).1Given the pathways for chemotherapy-induced nausea and vomiting described above, 5-HT3 and NK-1 receptor antagonists such as ondansetron and aprepitant, in combination with dopamine antagonists such as haloperidol, are typically effective for treatment of NV. In some cases, however, patients may develop breakthrough nausea and vomiting despite adequ...
Source: Pallimed: A Hospice and Palliative Medicine Blog - Category: Palliative Carer Workers Authors: Source Type: blogs