TABLE 1.

A list of drugs commonly used against toxoplasmosis^a

Drug(s)	References	Mechanism of action	In vitro IC50	Murine lethal challenge(s) and outcome (reference[s])
Pyrimethamine	15–20	Antifolate	0.4 μM	10 mg/kg/day, 20–90% survival, depending on parasite strain (18)
Dapsone, sulfadiazine, sulfadoxine, sulfamethoxazole	17, 19, 21–27	Antifolate	Dapsone, 1.2 μM; sulfadiazine, 1.6 μM; sulfamethoxazole, 395 μM	Dapsone, 100 mg/kg/day, 100% survival (24); sulfadiazine, 375 mg/kg/day, 100% survival (17); sulfamethoxazole, 600 mg/kg/day, 100% survival (26)
Clindamycin	17, 27–30	Protein synthesis inhibitor	0.005 μM	300 mg/kg/day, increased survival by 11 days (17)
Trimethoprim (typically combined with sulfamethoxazole)	21, 25, 26, 31	Antifolate	17.2 μM	70 mg/kg/day, 20% survival (26)
Atovaquone	27, 32, 33	Mitochondrial electron transfer chain inhibitor	0.82 μM	5 mg/kg/day, 20% survival (19)
Doxycycline, minocycline	34, 35	Apicoplast division inhibitor	Doxycycline, 14.4 μM	Doxycycline, 300 mg/kg/day, 100% survival (34)
Acetylspiramycin, azithromycin, clarithromycin, dirithromycin, erythromycin, roxithromycin, spiramycin, telithromycin, tylosin	18, 29, 36–41	Protein synthesis inhibitor	Azithromycin, 11.5 μM; clarithromycin, 401 μM; erythromycin, 19.6 μM; roxithromycin, 32.3 μM; spiramycin, 17.8 μM; telithromycin, 0.20 μM	Azithromycin, 200 mg/kg/day, 40–100% survival, depending on parasite strain (38); clarithromycin, 200 mg/kg/day, 80% survival (40); clarithromycin, 300 mg/kg/day, 100% survival (18); roxithromycin, 10 mg/day, 80–100% survival (36, 37); spiramycin, 400 mg/kg/day, no survival (38)

^aThe lowest observed IC₅₀ values are reported in cases in which multiple values were found in the literature. Moreover, wide variations exist in the method of murine lethal challenge between studies: differences include infectious dose, parasite strain, drug delivery route, time postinfection before treatment initiation, treatment length, and time of observed survival.