1. Allergic reactions. The most common are rashes and fevers. It usually occurs 5 to 9 days after medication, and is more common in children.
2. Kidney damage. Due to the low solubility of acetylated sulfonamide, especially when the urine is acidic, crystals are easily precipitated in the renal tubules, causing symptoms such as hematuria, dysuria, and urination.
3. Influence of hematopoietic system. Sulfa drugs can inhibit bone marrow leukocyte formation and cause leukopenia
4. Central nervous system and gastrointestinal reactions. Mostly due to the sufficient amount of sulfa.
Allergies to sulfa drugs are common. The overall incidence of adverse drug reactions to sulfa antibiotics is about 3%, which is close to penicillin
The most common are rashes and fevers. It usually occurs 5 to 9 days after medication, and is more common in children. There is cross-allergy between sulfa drugs, so it is not safe to switch to another sulfa drug when the patient is allergic to one sulfa drug. Once an allergic reaction occurs, the drug should be discontinued immediately. Long-acting sulfa drugs are very dangerous because they have a high binding rate to plasma proteins and there are drugs in the blood for several days after the drug is stopped.
Sulfonamide hypersensitivity syndrome is similar to anticonvulsant hypersensitivity syndrome, but usually develops earlier during treatment (usually 7 to 14 days after treatment).