PRIMARY PROPHYLAXIS AGAINST CEREBRAL TOXO PLASMOSIS - EFFECT OF FOLINIC ACID FOR THE PREVENTION OF HEMATOLOGIC TOXICITY OF PYRIMETHAMINE

Objectives: Cerebral toxoplasmosis is the most frequent opportunistic infection in patients with acquired immune deficiency syndrome in Fran ce, We evaluated the effect of adding folic acid to the standard treat ment (including pyrimethamine) on preventing induced cytopenia in orde r to determine the optimal dose.Methods: From January to September 199 0, pyrimethamine (50 mg 3 times per week) was given as primary prophyl axis against toxoplasmosis to 30 patients who were positive for human immunodeficiency virus (CDC classes II or II, CD4 counts < 200/mm(3)). The patients were randomly divided into three groups given 5, 25 and 0 mg folic acid 3 times per meek. Associated treatments were the same in all patients (zidovudine 600 mg/d, pentamidine ise thionate aerosol , 300 mg, once a month). Blood cell counts and lymphocyte subset count s were made on days 0, 30, 90 and 180. Results: Two patients were lost to follow up and between day 90 and 180, 3 were excluded due to other opportunist infection and 1 due to zidovudine induced anaemia. Betwee n the groups, there was no difference in haemoglobin level or cell cou nts on day 0. No haematologic toxicity was observed at day 90. Haemogl obin was significantly reduced in the control group (0 mg folic acid) on day 180 (mean haemoglobin on day 180, 13.8, 13.1 and 12.1 g/dl in g roups 1, 2 and 3 respectively). No variation in polynuclear neutrophil counts was observed. Conclusion: These findings suggest that folic ac id has a moderate beneficial effect on preventing haematologic disease in patients treated,vith pyrimethamine. There was no observed dose ef fect.