[Severe methemoglobinemia following large dose of nitrate medication].

A 49-year-old man with ischemic heart disease attempted to commit suicide by ingesting 300 tablets (6 grams) of isosorbide dinitrate. He was admitted with shortness of breath and cyanosis. Severe methemoglobinemia was diagnosed (blood level 47 mg%). After administration of intravenous methylene blue and fluids, there was immediate improvement and he was discharged 48 hours after admission.