Generic Name and Formulations:
Mercaptopurine (6-MP) 50mg; scored tabs.
Indications for PURINETHOL:
Maintenance therapy of acute lymphatic leukemia as part of a combination regimen.
Adults and Children:
1.5–2.5mg/kg per day as a single dose. Concomitant allopurinol: reduce dose of mercaptopurine to 1/3–1/4 of the usual dose. TPMT-deficient, renal or hepatic impairment: reduce dose, see literature.
Prior resistance to mercaptopurine.
Not effective in CNS leukemia, acute myelogenous leukemia, chronic lymphocytic leukemia, the lymphomas (including Hodgkin's disease), or solid tumors. Renal impairment. Monitor liver function tests weekly at start of therapy, then monthly thereafter; discontinue if hepatotoxicity occurs. Pre-existing liver disease (monitor more frequently). Obtain CBCs with differential, hemoglobin, hematocrit, platelets; discontinue if severe bone marrow suppression occurs. Thiopurine-S-methyltransferase (TPMT) deficient: increased risk of myelosuppression, consider genotypic/phenotypic testing. Pregnancy (Cat. D); esp. 1st trimester, nursing mothers: not recommended.
Increased risk of bone marrow suppression with allopurinol, aminosalicylate derivatives (eg, olsalazine, mesalazine, sulphasalazine), trimethoprim-sulfamethoxazole. Antagonizes warfarin. Caution with concomitant hepatotoxic agents.
Myelosuppression, hyperuricemia/hyperuricosuria, GI upset, intestinal ulceration, rash, hyperpigmentation, alopecia, oligospermia; hepatotoxicity, infection, immunosuppression.