Cancer chemotherapy and cachexia: mirtazapine and olanzapine are 5-HT3 antagonists with good antinausea effects.

Mirtazapine and olanzapine are easy-to-use psychiatric drugs with potent antinausea effects. Ondansetron and later members of the 'setron class are currently standard treatments for cancer chemotherapy-related nausea and emesis. They are potent 5-HT3 blockers, but it is often not appreciated that mirtazapine and olanzapine bind with similar affinity to 5-HT3 receptors, have a longer half-life, are considerably cheaper than the 'setron class, and often offer better and smoother 24-h nausea control than 'setron class drugs. Mirtazapine and olanzapine often have salutary antianxiety effects and improve sleep quality. They occasionally relieve chemotherapy-related and advanced cancer-related nausea and appetite decrease better than the 'setron group that are specifically marketed for nausea control. Mirtazapine and olanzapine frequently give potent nausea reduction and appetite increase in advanced cancer-related cachexia. Several cytokine changes potentially induced by mirtazapine and olanzapine use are discussed that may have salutary effects in several cancers. We suggest mirtazapine and olanzapine be included as first-line options in treating both chemotherapy- and advanced cancer-related nausea. Multiple clinical and economic advantages of mirtazapine and olanzapine over currently used 'setron class medicines are reviewed. Double-blind studies against the 'setron class drugs are warranted.