Key points
- Most people with healthy immune systems recover from toxoplasmosis without treatment.
- Drugs are available for those who require treatment.
Treatment options
Currently recommended treatment drugs for toxoplasmosis target the tachyzoite stage of the parasite and do not eradicate encysted parasites in the tissues. There are no drugs known to eradicate the encysted tissue stage.
Pyrimethamine, considered the most effective drug against toxoplasmosis, is a standard component of therapy. Pyrimethamine is a folic acid antagonist and can cause dose-related suppression of the bone marrow, which is mitigated by concurrent administration of folinic acid (leucovorin). Leucovorin protects the bone marrow from the toxic effects of pyrimethamine.
A second drug, such as sulfadiazine or clindamycin (if the patient has a hypersensitivity reaction to sulfa drugs), should also be included. The fixed combination of trimethoprim with sulfamethoxazole has been used as an alternative, as well as other drugs such as atovaquone and pyrimethamine plus azithromycin, which have not been extensively studied[1].
Treatment of immunocompetent adults with lymphadenopathic toxoplasmosis is rarely indicated; this form of the disease is usually self-limited. If visceral disease is clinically evident or symptoms are severe or persistent, treatment may be indicated for 2 to 4 weeks.
Treatment for ocular diseases should be based on a complete ophthalmologic evaluation. The decision to treat ocular disease is dependent on numerous parameters including acuteness of the lesion, degree of inflammation, visual acuity, and lesion size, location, and persistence. Healed lesions should not be treated. Management of ocular toxoplasmosis may vary depending on the treatment center, but usually consists of an anti-parasitic drug with corticosteroids as needed to control inflammation.
Ocular toxoplasmosis treatment
Drugs
Dosage
Directions
Pyrimethamine, sulfadiazine, folinic acid (leucovorin)
Adults: 100 mg for one day as a loading dose, then 25 – 50 mg per day, plus sulfadiazine 2 to 4 grams daily for 2 days, followed by 500mg to 1 gram dose 4x per day, plus folinic acid (leucovorin) 5-25 mg with each dose of pyrimethamine.
Children: pyrimethamine 2 mg/kg first day then 1 mg/kg each day, plus sulfadiazine 50 mg/kg two times per day, plus folinic acid (leucovorin) 7.5 mg per day)
Therapy should be given for 4 to 6 weeks, followed by reevaluation of the patient’s condition[2]. Corticosterioids are something prescribed in addition to antiparasitic agents.
Management of maternal and fetal infection varies depending on the treatment center. In general, spiramycin is recommended for women whose infections were acquired and diagnosed before 18 weeks gestation and infection of the fetus is not documented or suspected. Spiramycin acts to reduce transmission to the fetus and is most effective if initiated within 8 weeks of seroconversion. Spiramycin can be obtained from the U.S. Food and Drug Administration, telephone 301-796-1400. Pyrimethamine, sulfadiazine and leucovorin are recommended for infections acquired at or after 18 weeks gestation or infection in the fetus is documented or suspected. PCR is often performed on the amniotic fluid at 18 gestation weeks to determine if the infant is infected.
See additional information regarding management of toxoplasmosis in pregnant women.
Congenitally infected newborns are generally treated with pyrimethamine, a sulfonamide, and leucovorin for 12 months. Recommendations from the National Reference Laboratory for Toxoplasmosis (PAMF-TSL) and the Toxoplasmosis Center at the University of Chicago for treatment of congenitally infected infants[3] are:
Congenitally infected infant treatment
Drugs
Dosage
Pyrimethamine
Infants: 2 mg/kg per day orally, divided twice per day for the first 2 days; then from day 3 to 2 months (or 6 months if symptomatic) 1 mg/kg per day, orally, every day; then 1 mg/kg per day, orally, 3 times per week.
Sulfadiazine
Infants: 100 mg/kg daily 2 mg/kg per day, orally, divided twice per day.
Folinic acid (leucovorin)
Infants: 10 mg, 3 times per week
Toxoplasmosis in immunodeficient patients is often fatal if not treated. Treatment is recommended for at least 4 to 6 weeks beyond resolution of all clinical signs and symptoms but may be required for 6 months or longer. Relapses are known to occur in AIDS patients and maintenance therapy is recommended until a significant immunologic improvement is achieved in response to antiretroviral therapy. Pyrimethamine, folinic acid (leucovorin), and sulfadiazine are standards of therapy for immunodeficient patients.
Additional resources
Toxoplasma gondii Encephalitis | NIH (hiv.gov)
This information is provided as an informational resource for licensed health care providers as guidance only. It is not intended as a substitute for professional judgment.
Care precautions
Treatment in Pregnancy
Pyrimethamine is a pregnancy category C drug. Data on the use of pyrimethamine in pregnant women are limited. Pyrimethamine is commonly used in combination with sulfadiazine and folinic acid for treatment of fetal toxoplasmosis during the 2nd and 3rd trimesters. In malaria prevention interventions for which the World Health Organization (WHO) has determined that the benefit of treatment outweighs the risk, WHO allows use of pyrimethamine in combination with sulfadoxine in the 2nd and 3rd trimesters. Available evidence suggests avoiding pyrimethamine during the 1st trimester and supplementing pyrimethamine with folinic acid in pregnant women.
Pregnancy Category C: Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal, or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the fetus.
Treatment During Lactation
Pyrimethamine is excreted in breast milk. Both the American Academy of Pediatrics and the WHO classify pyrimethamine to be compatible with breast-feeding. Pyrimethamine when used in combination with other drugs should be used with caution in breast-feeding women.
Treatment in Pediatric Patients
The safety of pyrimethamine in children has not been established. In malaria prevention interventions for which the WHO has determined that the benefit of treatment outweighs the risk, WHO allows use of pyrimethamine in combination with sulfadoxine in children during the first year of life. Pyrimethamine is listed as an antipneumocystosis and antitoxoplasmosis medicine on the WHO Model List of Essential Medicines for Children, intended for the use of children up to 12 years of age.
Treatment in Pregnancy
Sulfadiazine is a pregnancy category C drug. Data on the use of sulfadiazine in pregnant women are limited. Available evidence suggests avoiding sulfonamides after week 32 of pregnancy. Sulfadiazine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Pregnancy Category C: Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal, or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the fetus.
Treatment During Lactation
Sulfadiazine is excreted in breast milk. The World Health Organization (WHO) recommends avoiding breastfeeding with sulfadiazine treatment. Sulfadiazine is contraindicated for use during lactation.
Treatment in Pediatric Patients
The safety of sulfadiazine in children has not been established. Use in children age 2 months and younger is contraindicated unless used in the treatment of congenital toxoplasmosis. Sulfadiazine is listed as an antipneumocystosis and antitoxoplasmosis medicine on the WHO Model List of Essential Medicines for Children, intended for the use of children up to 12 years of age.
Treatment in Pregnancy
Clindamycin is a pregnancy category B drug. Data on the use of clindamycin in pregnant women are limited, although no congenital anomalies have been reported. Clindamycin may be used during pregnancy in those patients who will clearly benefit from the drug.
Pregnancy Category B: Either animal-reproduction studies have not demonstrated a fetal risk but there are no controlled studies in pregnant women or animal-reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the first trimester (and there is no evidence of a risk in later trimesters).
Treatment During Lactation
Clindamycin is excreted in breast milk. The American Academy of Pediatrics classifies clindamycin as usually compatible with breastfeeding.
Treatment in Pediatric Patients
The parenteral form of clindamycin contains benzyl alcohol, which has been associated with a fatal "gasping syndrome" in premature infants.
Treatment in Pregnancy
Trimethoprim–sulfamethoxazole (TMP–SMX) is a pregnancy category C drug. TMP–SMX should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. TMP-SMX should be avoided near-term because of the potential for hyperbilirubinemia and kernicterus in the newborn.
Pregnancy Category C: Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal, or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the fetus.
Treatment During Lactation
Trimethoprim–sulfamethoxazole (TMP–SMX) is excreted in breast milk. TMP–SMX generally is compatible with breastfeeding of healthy, full-term infants after the newborn period. However, TMP-SMX generally should be avoided by women when nursing infants who are premature, jaundiced, ill, or stressed, or who have glucose-6-phosphate dehydrogenase deficiency.
Treatment in Pediatric Patients
The safety of trimethoprim–sulfamethoxazole (TMP–SMX) in children has not been systematically evaluated. Use in children less than 2 months of age generally is not recommended.
References
- Montoya JG, Boothroyd JC, Kovacs JA. Toxoplasma gondii in Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 8th, Edition, 2017 Mandell GL, Bennett JE, Dolin R, Eds. Churchill Livingstone Elsevier, Philadelphia, PA.
- de-la-Torre A, Stanford M, Curi A, Jaffe GJ, Gomez-Marin JE. Therapy for ocular toxoplasmosis. Ocul Immunol Inflamm. 2011;19:314-20.
- Maldonado YA, Read JS, AAP Committee on Infectious Diseases. Diagnosis, Treatment, and Prevention of Congenital Toxoplasmosis in the United States.external iconPediatrics. 2017;139(2):e20163860