If you have a sulfa allergy, you should avoid antibiotics such as Bactrim or Septra (TMP/SMX, trimethoprim-sulfamethoxazole). Trimethoprim-sulfamethoxazole is the most commonly used sulfa antibiotic.

Sulfamethoxazole 800mg ... Folate or G6PD deficiency. Severe allergy or bronchial asthma. Circulatory shock. Malnutrition. Porphyria or thyroid dysfunction. Disorders of potassium metabolism.

Sulfamethoxazole 400mg ... Folate or G6PD deficiency. Severe allergy. Bronchial asthma. Circulatory shock. Malnutrition. Porphyria. Thyroid dysfunction. Disorders of potassium metabolism.