To evaluate the efficacy of WR 6026 once daily in the treatment of mild PCP. To evaluate the safety and tolerance of WR 6026. To assess the correlation between plasma WR 6026 concentrations and outcome/toxicity.

All patients will receive an initial loading dose of WR 6026, followed the next morning and each morning thereafter by 1 of 2 lower doses of WR 6026 taken in a fasting state for 3 weeks.

Inclusion Criteria

Concurrent Medication:

Allowed:

• Any medications not listed as excluded will be permitted on study.

[ AS PER AMENDMENT 4/11/97:PCP prophylaxis is permitted if initiated after the Day 21 evaluation has been completed.]

Patients must have:

• Documented HIV infection.
• Documented PCP.
• On a room air ABG, the PO2 value greater than or equal to 70 mm Hg and the (A-a) DO2 less than 35 mm Hg.
• Signed informed consent from parent or legal guardian for those patients less than 18 years of age.

Exclusion Criteria

Co-existing Condition:

Patients with the following symptoms or conditions are excluded:

• Known hypersensitivity to quinolines.
• If patient is unwilling or unable to discontinue other medications with anti-PCP activity during the treatment period of this study.

Concurrent Medication:

Excluded:

• Any patient unwilling or unable to discontinue other medications with anti-PCP activity during the treatment period of this study (e.g., TMP/SMX, sulfonamides, dapsone, pentamidine, trimetrexate, atovaquone, clindamycin, azithromycin, pyrimethamine, primaquine).
• Methemoglobinemia-producing agents (dapsone, primaquine, sulfonamides, chloroquine, nitrofurantoin, nitrates and nitrites).

Patients with the following prior conditions or symptoms are excluded:

• History of G6PD deficiency, hemoglobin M abnormality, or NAD methemoglobin reductase deficiency.

Prior Medication:

Excluded:

• More than 24 hours receipt of anti-PCP treatment for the current episode of PCP. Receipt of prior PCP prophylaxis is permitted, as long as it is discontinued at study entry.