Which of the following medications essential for ameliorating the toxicity of pemetrexed:

Ans. b. Folic acid and vitamin B12 Pemetrexed Toxicity Pemetrexed toxicity mirrors that of methotrexate, with the additional feature of a prominent erythematous and pruritic rash in 40% of patientsQ. Dexamethasone, 4 mg twice daily on days -1, 0 and +1, markedly diminishes this toxicity. Unpredictably, severe myelosuppression with pemetrexed, seen especially in patients with pre-existing homocysteinemia and possibly reflecting folate deficiency, is largely eliminated by concurrent administration of low dosages of folic acid, 350-1000 mg/day, beginning 1-2 weeks prior to pemetrexed and continuing while the drug is administered. Patients should receive intramuscular vitamin B12 (1 mg) with the first dose of pemetrexed to correct possible B12 deficiency. These small doses of folate and B12 do not compromise the therapeutic effects.