Low-dose trimethoprim-sulfamethoxazole prophylaxis for toxoplasmic encephalitis in patients with AIDS.
OBJECTIVE
To determine the efficacy of low-dose trimethoprim-sulfamethoxazole (trimethoprim, 160 mg plus sulfamethoxazole, 800 mg; one tablet twice daily, 2 days per week) as primary prophylaxis against toxoplasmic encephalitis in patients with human immunodeficiency virus (HIV) infection and previous Pneumocystis carinii pneumonia.


METHODS
A retrospective study.


METHODS
Tertiary referral teaching hospital.


METHODS
During a 3-year period after primary episodes of P. carinii pneumonia, 60 patients received trimethoprim-sulfamethoxazole, and 95 patients received pentamidine (aerosolized in 78 patients and intravenous in 17 patients) as secondary prophylaxis.


RESULTS
No patient in the trimethoprim-sulfamethoxazole group and no patient seronegative for Toxoplasma gondii developed toxoplasmic encephalitis, compared with 12 of 36 (33%; 95% Cl, 19% to 51%) seropositive patients in the pentamidine group (trimethoprim-sulfamethoxazole compared with pentamidine, P = 0.008). A significant difference was seen in the time to development of toxoplasmic encephalitis between the trimethoprim-sulfamethoxazole group (no case at 1153 days) and the pentamidine group (median time, 460 days) (P = 0.004). Neither the CD4+ lymphocyte count at the start of prophylaxis nor zidovudine therapy during the period of prophylaxis influenced the rate of toxoplasmic encephalitis in any group.


CONCLUSIONS
Low-dose trimethoprim-sulfamethoxazole (four tablets per week) appears to be effective prophylaxis against toxoplasmic encephalitis in HIV-infected patients with previous P. carinii pneumonia. A prospective, randomized, controlled study is needed to further evaluate these findings.
St. Vincent's Hospital, Sydney, Australia.
A
A
Carr
B
B
Tindall
B J
BJ
Brew
D J
DJ
Marriott
J L
JL
Harkness
R
R
Penny
D A
DA
Cooper
D000163:Acquired Immunodeficiency Syndrome / Q000150:complications*; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D015496:CD4-Positive T-Lymphocytes; D004660:Encephalitis / Q000209:etiology / Q000469:parasitology / Q000517:prevention & control*; D005500:Follow-Up Studies; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007958:Leukocyte Count; D008297:Male; D010419:Pentamidine / Q000627:therapeutic use; D011020:Pneumonia, Pneumocystis / Q000209:etiology / Q000517:prevention & control; D012189:Retrospective Studies; D014122:Toxoplasma / Q000276:immunology; D016781:Toxoplasmosis, Cerebral / Q000209:etiology / Q000517:prevention & control*; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000009:adverse effects / Q000627:therapeutic use*; D015215:Zidovudine / Q000627:therapeutic use
D000913:Antibodies, Protozoan; D007074:Immunoglobulin G; D015215:Zidovudine; D010419:Pentamidine; D015662:Trimethoprim, Sulfamethoxazole Drug Combination