The Drug-Induced Respiratory Disease Website
Known since the 1940s (PMID 18883450). Comprehensive list of causal drugs and chemicals available at PMID 1564446. Methemoglobin is the oxidized (Fe3+) species of hemoglobin (Fe2+). Patients present with slate-grey cyanosis, low SpO2, normal SaO2 and PaO2. Normally, methemoglobin is <1%. Levels above 40% can be life-threatening, producing pulmonary edema, cardiovascular collapse (PMID 17122537) CNS disturbances and death. Management includes i.v. methylene blue. A possible rebound increase in MeHb upon treatment requires close monitoring. Excess methylene blue can also produce methemoglobinemia. Guidelines: PMID 34467556.
Publications
Methemoglobinemia induced by trimethoprim-sulfamethoxazole in a patient with systemic lupus erythematosus.
Internal medicine (Tokyo, Japan) 2013;52;1741-3 — 2013 — 1741-3
Use of telemedicine for the identification and treatment of sulfamethoxazole-induced methaemoglobinemia.
Journal of telemedicine and telecare 2012 Sep;18;362-4 — 2012 Sep — 362-4
Methaemoglobinaemia secondary to treatment with trimethoprim and sulphamethoxazole associated with inhaled nitric oxide.
Acta paediatrica (Oslo, Norway : 1992) 1999 Aug;88;915-6 — 1999 Aug — 915-6