Methemoglobinemia may be caused by all of the following drugs, EXCEPT:
Drugs causing methemoglobinemia are: Nitrous gases, chloroquine and primaquine, phenazopyridine, sulfonamides, sulfones, aniline dye derivatives, phenacetin, dapsone, local anesthetics, and nitrobenzenes. Hemoglobin becomes methaemoglobin when iron is oxidized from the ferrous to the ferric form. This conversion of hemoglobin to methaemoglobin result in tissue hypoxia by decreasing both delivery of oxygen and removal of carbon dioxide. When levels of methaemoglobin exceeds : 10% of total haemoglobin: cyanosis without any shoness of breath 15% of total haemoglobin: blood appears chocolate brown 25% of total haemoglobin: peripheral and perioral cyanosis 35-40% of total haemoglobin: patients experience lassitude, fatigue, and dyspnea 60% of total haemoglobin: coma and death may occur Ref: Morgan D.L., Borys D.J. (2011). Chapter 47. Poisoning. In R.L. Humphries, C. Stone (Eds), CURRENT Diagnosis & Treatment Emergency Medicine, 7e.
Sulfonamides
Phenytoin
Phenacetin
Nitrobenzenes