Answer
Apr 30, 2026 - 08:21 AM
A serious side effect of trimethoprim-sulfamethoxazole is severe allergic reactions, such as Stevens-Johnson syndrome or toxic epidermal necrolysis, which can be life-threatening. Other serious side effects include blood disorders like agranulocytosis or aplastic anemia. If you experience symptoms like rash, blistering skin, or unusual bleeding, seek medical attention immediately.
