Treatment of Congenital Toxoplasmosis: Safety of the Sulfadoxine-Pyrimethamine Combination in Children Based on a Method of Causality Assessment.

The treatment of newborns and infants with congenital toxoplasmosis is standard practice. Some observational studies have examined safety in newborns, but most of these failed to provide sufficient details for a provisional assessment of causality. The aim of this study was to evaluate the clinical and biological adverse effects of the combination of sulfadoxine-pyrimethamine.

Sixty-five children treated for 1 year with a combination of sulfadoxine-pyrimethamine (1 dose every 10 days) for congenital toxoplasmosis were followed up to evaluate abnormal hematological values and potential adverse events using a standardized method of causality assessment.

Nine patients (13.8%) presented at least 1 adverse clinical event that was nonspecific, such as diarrhea on the day of drug administration, vomiting and agitation. In 1 patient, erythema appeared at the end of the treatment and resolved within 10 days. None of these events was attributed to the treatment. Six patients (9.2%) developed an adverse hematological event (neutropenia, n = 3; eosinophilia, n = 2 and both anemia and eosinophilia, n = 1) that was considered to be possibly related to the sulfadoxine-pyrimethamine combination. Four treatments were temporarily interrupted, and toxicity was observed after readministration of treatment in 1 case only. However, none of these adverse events was life threatening.

According to our results and previously published data, the combination of sulfadoxine-pyrimethamine seems to be well tolerated. However, the sample size of our study was too small to rule out the risk of less frequent, but nevertheless severe, reactions and, in particular, of hypersensitivity reactions.