Treatment of Toxoplasmosis

Treatment by Clinical Scenario

The American Academy of Pediatrics recommends pyrimethamine plus sulfadiazine plus leucovorin as the gold standard for active disease in immunocompromised patients and congenital infection 1, 2
For infants with confirmed congenital toxoplasmosis, the standard regimen is pyrimethamine plus sulfadiazine plus leucovorin for 12 months, with pyrimethamine dosing at 2 mg/kg/day for 2 days, then 1 mg/kg/day for 2-6 months, followed by 1 mg/kg three times weekly 1, 2
The Centers for Disease Control and Prevention recommends spiramycin 1 g (3 million IU) orally three times daily for pregnant women with suspected maternal infection but no confirmed fetal involvement, until delivery if amniocentesis is negative and fetal ultrasound shows no abnormalities 1, 4, 5

The Centers for Disease Control and Prevention recommends pyrimethamine plus sulfadiazine plus leucovorin for at least 6 weeks as the preferred acute treatment for toxoplasmic encephalitis in HIV/AIDS patients, assuming clinical and radiological improvement 6, 7, 3
After acute therapy, lifelong secondary prophylaxis (chronic maintenance therapy) is required to prevent relapse unless immune reconstitution occurs with HAART, with secondary prophylaxis able to be discontinued if CD4+ count increases to >200 cells/µL for ≥6 months on HAART 6, 7

The Centers for Disease Control and Prevention recommends that all HIV-infected patients should be tested for Toxoplasma IgG antibody at initiation of care, with toxoplasma-seropositive patients with CD4+ count <100 cells/µL receiving prophylaxis against toxoplasmic encephalitis 2, 6, 7
The preferred regimen for primary prophylaxis is TMP-SMX double-strength tablet daily, which also protects against PCP 6, 7, 2

Pyrimethamine-sulfadiazine therapy carries significant risk of bone marrow suppression, particularly neutropenia, especially when leucovorin is not administered, with adverse events occurring in 20-50% of treated infants in some series 8, 9
The American College of Obstetricians and Gynecologists recommends consultation with specialists for pregnant women with suspected or confirmed primary toxoplasmosis 2