A client with leukemia is receiving Trimetrexate. After reviewing the client’s chart, the physician orders Wellcovorin (leucovorin calcium). The rationale for administering leucovorin calcium to a client receiving Trimetrexate is to:
A. Treat iron-deficiency anemia caused by chemotherapeutic agents
B. Create a synergistic effect that shortens treatment time
C. Increase the number of circulating neutrophils
D. Reverse drug toxicity and prevent tissue damage
Correct Answer: D. Reverse drug toxicity and prevent tissue damage
Leucovorin is the antidote for Methotrexate and Trimetrexate which are folic acid antagonists. Leucovorin is a folic acid derivative. Leucovorin is FDA indicated after high dose methotrexate therapy in osteosarcoma, to decrease the toxic effects of methotrexate or to counter the toxic effects of folate antagonists. Leucovorin is also occasionally an alternative agent used in the treatment of megaloblastic anemia when oral intake of folic acid is not possible.
Option A: Leucovorin does not treat iron deficiency. Off-label uses include as neoadjuvant treatment in bladder cancer, as a cofactor in methanol toxicity, in the treatment of advanced esophageal cancer, advanced gastric cancer, advanced pancreatic cancer, prevention of hematological toxicity of pyrimethamine in patients with AIDS, and the treatment of ectopic pregnancy (along with methotrexate).
Option B: Leucovirin does not create a synergistic effect when taken with Trimextrate. When used as a part of chemotherapeutic regimens, leucovorin is not administered along with methotrexate. It is usually administered 24 hours after a course of methotrexate. Tissue toxicity may be permanent if leucovorin therapy gets delayed beyond 40 hours.
Option C: An increase in neutrophils is not an effect of Leucovirin. Folic acid in large quantities has been shown to counteract the pharmacological actions of antiepileptics such as primidone, phenobarbital, and phenytoin. When leucovorin has been used concomitantly during the treatment of Pneumocystis jirovecii with trimethoprim-sulfamethoxazole (TMP-SMX), higher rates of treatment failure and morbidity have been reported.