Table 1.

Drugs or toxins that can cause methemoglobinemia*

Acetanilid Alloxan Aniline Arsine Benzene derivatives Benzocaine Bivalent copper Bismuth subnitrate Bupivacaine hydrochloride Chlorates Chloroquine Chromates Clofazimine Dapsone Dimethyl sulfoxide Dinitrophenol Exhaust fumes Ferricyanide Flutamide Hydroxylamine Lidocaine hydrochloride Metoclopramide hydrochloride Methylene blue Naphthalene Nitrates Nitric oxide Nitrites Nitrofuran Nitroglycerin Sodium nitroprusside Paraquat Phenacetin Phenazopyridine hydrochloride Phenol Phenytoin Prilocaine hydrochloride Primaquine phosphate Rifampin Silver nitrate Sodium valproate Smoke inhalation Sulfasalazine Sulfonamides Trinitrotoluene

^*Certain drugs are more likely to cause methemoglobinemia than others. These are dapsone, local anesthetics, phenacetin, and antimalarial drugs. Screening everybody for methemoglobinemia before exposing them to these drugs is impractical because of the rarity of the condition and because a growing number of drugs are implicated in its causation.