Which of the following agents is commonly used in combination with 5-HT3 antagonists to treat chemotherapy-induced nausea?

The use of corticosteroids in combination with 5-HT3 antagonists is well-established in the management of chemotherapy-induced nausea and vomiting (CINV). Corticosteroids, such as dexamethasone, enhance the efficacy of 5-HT3 antagonists by providing an additional mechanism for controlling nausea. While 5-HT3 antagonists work primarily on serotonin receptors to inhibit vomiting signals in the brain and gut, corticosteroids appear to have anti-inflammatory effects, which may further help reduce nausea and vomiting associated with chemotherapy. This combination approach is often part of a multimodal strategy that optimizes patient comfort during cancer treatment.

In contrast, antibiotics, analgesics, and antihistamines do not have the same role or established efficacy when it comes to treating CINV in conjunction with 5-HT3 antagonists. Antibiotics are used to treat infections, analgesics are focused on pain relief, and while antihistamines can have anti-nausea properties, they do not specifically enhance the action of 5-HT3 antagonists in the context of chemotherapy. Therefore, corticosteroids are the agents that are commonly recommended alongside these antagonists for better management of CINV.