cisplatin + dexamethasone + vitamin B12 + folic acid

This is a **combination regimen consisting of cisplatin, dexamethasone, vitamin B12, and folic acid**. Each component serves a distinct purpose: - **Cisplatin** is a platinum-based chemotherapeutic agent used primarily for various solid tumors by causing DNA crosslinking and apoptosis. - **Dexamethasone** is a synthetic glucocorticoid corticosteroid used to reduce chemotherapy-induced nausea, vomiting, and inflammation[2][6]. - **Vitamin B12** and **folic acid** are dietary supplements administered to reduce hematologic and non-hematologic toxicities associated with chemotherapy, especially important when used with antifolate chemotherapies like pemetrexed in regimens that often also include cisplatin[1][5][7]. This specific four-drug combination is not a standard combination therapy with a unique brand name, but the **co-administration of dexamethasone, vitamin B12, and folic acid is commonly recommended in protocols with pemetrexed/cisplatin** chemotherapy to minimize toxicity and side effects. Mechanistically, cisplatin acts through DNA crosslinking, dexamethasone acts via glucocorticoid receptor agonism to modulate immune and inflammatory responses and suppress nausea, while vitamin B12 and folic acid support DNA synthesis and repair, reducing chemotherapy-induced cytopenias and mucositis.