Efficacy of a hydroxynaphthoquinone, 566C80, in experimental Pneumocystis carinii pneumonitis

W. T. Hughes, V. L. Gray, W. E. Gutteridge, V. S. Latter, M. Pudney

Research output: Contribution to journalArticlepeer-review

104 Scopus citations


The efficacy of a new class of drugs for Pneumocystis carinii pneumonitis was demonstrated. 566C80, a hydroxynaphthoquinone, administered orally in a dose of ≥ 100 mg/kg of body weight per day prophylactically prevented P. carinii pneumonitis in 90% or more of rats, while all untreated control animals developed pneumonitis. When 566C80 (100 mg/kg per day) was administered for 3 weeks after P. carinii pneumonitis was established, therapy was totally effective and all of the untreated controls had progressive P. carinii pneumonitis. A dose of 566C80 of between 25 and 50 mg/kg per day protected 50% of the rats from P. carinii pneumonitis, and a dose of between 50 and 100 mg/kg per day cured 50% of those treated for P. carinii pneumonitis. Both prophylaxis and treatment with 566C80 were at least as effective as with trimethoprim-sulfamethoxazole. Animals maintained on immunosuppression after completion of treatment remained free of P. carinii, suggesting a killing effect. Clearance of P. carinii was associated with levels of 60 μg or more of 556C80 per ml of plasma. This hydroxynaphthoquinone offers promise as an anti-P. carinii drug.

Original languageEnglish (US)
Pages (from-to)225-228
Number of pages4
JournalAntimicrobial agents and chemotherapy
Issue number2
StatePublished - 1990
Externally publishedYes

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)
  • Infectious Diseases


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