sulfamethoxazole
Drug class
Active ingredient: sulfamethoxazole
- Intermediate-acting sulfonamidesATC code: J01EC01Source: ATC
Allergy cross-reactivity
Cross-reactivity among sulfonamide antibiotics
Risk level: Moderate
Basis: Sulfonamide antibiotics share both the N1 heterocyclic ring and the N4 arylamine group implicated in immunologic hypersensitivity.
Other active ingredients in the same group:
- sulfadiazine
- sulfasalazine
Notes: Risk is real but not absolute. In severe reactions (SJS/TEN, DRESS) avoid re-challenge. Never give a binary safe/allergic verdict — consult a specialist.
Source: https://pubmed.ncbi.nlm.nih.gov/14573734/
Cross-reactivity risk is not definitive; consult an allergy/infectious disease specialist.
Breastfeeding
LactMed
Risk level: Caution
Acceptable in healthy term infants; avoid in newborns, jaundice, G6PD deficiency, ill/premature (bilirubin displacement).
Source: https://www.ncbi.nlm.nih.gov/books/NBK501290/
Breastfeeding safety requires individual assessment; consult a physician.