Alternative treatment approach to cerebral toxoplasmosis in HIV/AIDS: experience from a resource-poor setting

The current standard treatment for cerebral toxoplasmosis (pyrimethamine/sulfadiazine) often encounters problems of poor tolerability, adverse effects, frequent dropouts and non-availability of pyrimethamine/sulfadiazine in some parts of India. We have had to use the combination of two effective alternative agents for toxoplasmosis, cotrimoxazole and clindamycin, on compassionate grounds. This retrospective observational study reports superior efficacy and better tolerability of cotrimoxazole/clindamycin compared to the recommended regimen. Primary end-point (complete response) was defined as more than 50% improvement of clinical status or more than 50% decrease in the size of brain lesions after two weeks of treatment initiation. Complete response occurred more commonly with cotrimoxazole/clindamycin than with pyrimethamine/sulfadiazine group (80% vs. 31.25%, respectively, relative risk 2.56, 95% confidence interval: 1.21-5.43). There was a trend towards higher on-treatment mortality in the pyrimethamine/sulfadiazine group in comparison to the cotrimoxazole/clindamycin (mortality rate 37.5% in pyrimethamine/sulfadiazine vs 12% in cotrimoxazole/clindamycin, p=0.07, relative risk=3.125, 95% confidence interval: 0.91-10.75). Overall, 62.5% (10/16) of patients on pyrimethamine/sulfadiazine suffered drug-related adverse reactions compared to 24% (6/25) on cotrimoxazole/clindamycin (p=0.02, relative risk=2.60, 95% confidence interval: 1.17-5.76). The commonest complication of pyrimethamine/sulfadiazine was severe thrombocytopenia with major bleeding (4/16, 25%). We propose that the new combination chemotherapy, which is widely available, effective and safe, can be used in developing countries.