Severe Megaloblastic Anemia Complicating Pyrimethamine Therapy
Authors: John P. Chute
Journal: Annals of Internal Medicine (1995)

Letters1 June 1995Severe Megaloblastic Anemia Complicating Pyrimethamine TherapyJohn P. Chute, MD, Catherine F. Decker, MD, and James Cotelingam, MDJohn P. Chute, MDFrom National Naval Medical Center, Bethesda, MD 20889-5000., Catherine F. Decker, MDFrom National Naval Medical Center, Bethesda, MD 20889-5000., and James Cotelingam, MDFrom National Naval Medical Center, Bethesda, MD 20889-5000.Author, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-122-11-199506010-00030 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail TO THE EDITOR:With the growing acquired immunodeficiency syndrome (AIDS) epidemic, the use of pyrimethamine and sulfadiazine in the treatment of central nervous system toxoplasmosis has increased. Pyrimethamine exerts its antiparasitic effect by inhibiting the enzyme dihydrofolate reductase, which the parasite requires for DNA synthesis. By the same mechanism, pyrimethamine can also potentially cause megaloblastic anemia by depleting folic acid stores ([1]). At the dosages regularly used in humans, pyrimethamine alone does not commonly cause substantial megaloblastic anemia. The ability of pyrimethamine to inhibit the dihydrofolate reductase enzyme has been shown to be relatively selective to the parasite ([2]).We ...References1. Waxman S, Herbert V. Mechanism of pyrimethamine induced megaloblastosis test in human bone marrow. N Engl J Med. 1969;280:1316-9. CrossrefMedlineGoogle Scholar2. Hitchings GH. Species differences among dihydrofolate reductases as a basis for chemotherapy. Post Grad Med J Suppl. 1969;45:7-10. MedlineGoogle Scholar3. Cohn JA, McMeeking A, Cohen W, Jacobs J, Holzman RS. Evaluation of the policy of empiric treatment of suspected toxoplasma encephalitis in patients with the acquired immunodeficiency syndrome. Am J Med. 1989;86:521-7. CrossrefMedlineGoogle Scholar4. Haverkos HW. Assessment of therapy for toxoplasma encephalitis: the TE Study Group. Am J Med. 1987;82:907-14. CrossrefMedlineGoogle Scholar5. Jacobson MA, Besch CL, Child C, Hafner C, Matts JP, Muth K, et al . Primary prophylaxis with pyrimethamine for toxoplasmic encephalitis in patients with advanced human immunodeficiency virus disease: results of a randomized trial. J Infect Dis. 1994;169:384-94. CrossrefMedlineGoogle Scholar Author, Article, and Disclosure InformationAuthors: John P. Chute, MD; Catherine F. Decker, MD; James Cotelingam, MDAffiliations: From National Naval Medical Center, Bethesda, MD 20889-5000. PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetails Metrics Cited byPyrimethamineClinicopathologic characteristics and outcomes of patients experiencing severe pyrimethamine poisoningANTIPROTOZOAL AND ANTIHELMINTHIC DRUGSBilateral macular hemorrhage as a complication of drug-induced anemia: a case reportAssessment of safety of the major antimalarial drugsPyrimethamineRefractory megaloblastic anemia in a patient with AIDS: Response to danazolPancytopénie maternelle au cours du traitement anténatal d'une toxoplasmose congénitaleAntimalarial Drug ToxicityCerebral Infarction in Adult AIDS PatientsPyrimethamine 1 June 1995Volume 122, Issue 11Page: 884-885KeywordsCentral nervous systemHIVHemorrhageMegaloblastic anemiaPlateletsProphylaxisPyrimethamineResearch laboratoriesToxicityToxoplasmosis ePublished: 15 August 2000 Issue Published: 1 June 1995 Copyright & PermissionsCopyright © 1995 by American College of Physicians. All Rights Reserved.PDF downloadLoading ...