Is ivermectin effective for treating toxoplasmosis?

Ivermectin is Not Effective for Treating Toxoplasmosis

Ivermectin is not recommended or effective for the treatment of toxoplasmosis based on current guidelines. 1

Current Treatment Recommendations for Toxoplasmosis

The treatment of toxoplasmosis depends on the clinical scenario:

Preferred Treatment Regimens

• Pyrimethamine plus sulfadiazine with folinic acid is the standard treatment for confirmed toxoplasmosis 1
• Spiramycin is commonly used for maternal toxoplasmosis infection during pregnancy to prevent transmission to the fetus 2, 3
• Trimethoprim-sulfamethoxazole (co-trimoxazole) is an alternative treatment option, particularly in combination with spiramycin 1, 3

Treatment Efficacy Evidence

• Combination therapy with spiramycin plus trimethoprim-sulfamethoxazole has shown better efficacy in reducing maternal-fetal transmission compared to spiramycin alone (8.2% vs 20% transmission rates) 3
• Pyrimethamine plus sulfadiazine showed a trend toward lower transmission rates compared to spiramycin alone in pregnant women (18.5% vs 30%) 4
• No cerebral ultrasound anomalies were observed in fetuses whose mothers received pyrimethamine plus sulfadiazine, compared to 6 cases in the spiramycin group 4

Why Ivermectin is Not Used for Toxoplasmosis

Ivermectin is not mentioned in any guidelines for toxoplasmosis treatment. Instead, it is indicated for:

• Scabies treatment at a dose of 200μg/kg orally, repeated in 2 weeks 1
• Pediculosis pubis (pubic lice) at a dose of 250μg/kg repeated in 2 weeks 1
• Strongyloides stercoralis infection 1
• Cutaneous larva migrans at a dose of 200μg/kg as a single dose 1
• Onchocerciasis treatment at 200μg/kg monthly for 3 months 1

Important Considerations When Selecting Anti-Parasitic Treatments

Safety in Special Populations

• Ivermectin is considered to have "human data suggest low risk" in pregnancy and is probably compatible with breastfeeding 1
• Very low levels of ivermectin are excreted into breast milk, making it likely compatible with breastfeeding 1
• Ivermectin should be taken with food because bioavailability is increased, thereby increasing penetration of the drug 1

Precautions with Ivermectin

• Ivermectin has limited ovicidal activity and may not prevent recurrences from eggs at the time of treatment, necessitating repeat dosing 1
• Dose adjustments are not required in patients with renal impairment, but the safety of multiple doses in patients with severe liver disease is not known 1
• One study demonstrated increased mortality among elderly, debilitated persons who received ivermectin, though this observation has not been confirmed in subsequent reports 1

Conclusion

For toxoplasmosis treatment, the evidence supports using pyrimethamine plus sulfadiazine, spiramycin (especially in pregnancy), or trimethoprim-sulfamethoxazole, depending on the clinical scenario. Ivermectin has no established role in toxoplasmosis treatment according to current guidelines and should not be used for this indication.