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June 1959

Pharmacological Studies of Pyrimethamine (Daraprim) in Man

Author Affiliations

Bethesda, Md.
From the Ophthalmology Branch, National Institute of Neurological Diseases and Blindness. National Institutes of Health, Public Health Service, U. S. Department of Health, Education, and Welfare.

AMA Arch Ophthalmol. 1959;61(6):885-890. doi:10.1001/archopht.1959.00940090887003

Pyrimethamine (Daraprim) has been shown to kill proliferative Toxoplasmas in vivo and in vitro.1,2 Although it is used for the treatment of toxoplasmosis and malaria in man, few observations on its pharmacology have been made in humans maintained on the drug.

In antimicrobial therapy it is generally desirable to attain as rapidly as possible the highest concentration of a therapeutic agent consistent with acceptable levels of toxicity. The present study was undertaken (1) to determine an optimal therapeutic regimen for rapidly achieving high serum concentrations of pyrimethamine, (2) to elucidate the serum concentrations of the drug that are thereby achieved in man, and (3) to see whether a relation exists between the serum level of pyrimethamine and the bone marrow toxicity.

Methods and Materials  Nineteen patients being treated with pyrimethamine and sulfonamides were divided into three groups: 1. Multiple serum pyrimethamine assays were done on eight patients receiving 25