Drugs or toxins that cause methaemoglobinaemia

Acquired methaemoglobinaemia occurs with exposure to certain oxidants. Most cases are due to the following drugs and toxins:

• nitrites and nitrates
  • nitrites and nitrates found in well water
  • sodium nitrite (eg in preserved foods, some liniments and laxatives)
  • sodium nitroprusside, glyceryl trinitrate
  • amyl nitrite (a recreational drug commonly known as a 'popper' or 'rush')
• local anaesthetics—commonly prilocaine, benzocaine; occasionally lidocaine, articaine, tetracaine (amethocaine)
• antibiotics—sulfonamides, dapsone
• antimalarials—commonly chloroquine, primaquine
• pesticides
• herbicides—paraquat, propanil
• aniline dyes, nitrobenzene
• naphthalene
• potassium permanganate
• fertilisers.

People with glucose-6-phosphate dehydrogenase (G6PD) deficiency have an increased susceptibility to methaemoglobinaemia following minimal or therapeutic exposure to the oxidants listed above.