Recurrent pancreatitis after trimethoprim-sulfamethoxazole rechallenge.

We report a female patient who repeatedly developed pancreatitis after trimethoprim-sulfamethoxazole (TMP/SMX) use. During childhood she had undergone an ureterosigmoidostomy after which she had been on TMP/SMX 480 mg daily as prophylaxis for pyelonephritis for many years. The patient presented with abdominal pain caused by acute pancreatitis. No other cause, except for TMP/SMX use, could be identified. A causal relationship was confirmed by relapse of the pancreatitis after rechallenge. Our case is unique in demonstrating that acute pancreatitis related to the use of TMP/SMX may occur even after long-term treatment. We advise that the medication is discontinued immediately if a causal relationship with pancreatitis is suspected.