Trimethoprim associated aseptic meningitis.

We report 5 patients with repeated episodes of meningitis related to intake of trimethoprim containing compounds. On at least one occasion the patients received pure trimethoprim prior to reaction. Autoimmune disease was established in 3 of the patients. A close temporal relationship between drug intake and reaction was noted: symptoms appeared often within minutes. No evidence of infections was found. Lumbar puncture after recovery revealed normal values in 2 patients. This aseptic meningitis is most likely an adverse drug reaction and associated with trimethoprim intake. The reaction is infrequently reported in relation to drug sales but its incidence has probably been underestimated.