Ja. Vick et Jd. Vonbredow, EFFECTIVENESS OF INTRAMUSCULARLY ADMINISTERED CYANIDE ANTIDOTES ON METHEMOGLOBIN FORMATION AND SURVIVAL, Journal of applied toxicology, 16(6), 1996, pp. 509-516
Successful first aid therapy for cyanide intoxication is dependent upo
n immediate administration of antidotes which directly or indirectly i
nteract with the cyanide ion to remove it from circulation. Owing to t
he severe respiratory, cardiovascular and convulsive episodes followin
g acute cyanide intoxication, the most practical approach is to admini
ster antidotes by intramuscular injection, Exceptionally rapid methemo
globin formers-hydroxylamine hydrochloride (HH) and dimethylaminopheno
l (DMAP)-are usually able to prevent the lethal effect of cyanide foll
owing intramuscular injections in doses sufficient to induce 20% methe
moglobin (HH = 20 mg kg(-1) and DMAP = 2 mg kg(-1)). Sodium nitrite, t
he methemoglobin inducer approved for military use, must be administer
ed by intravenous infusion because it is not an effective cyanide anti
dote by the intramuscular route, In the normal unintoxicated animal an
intramuscular injection of 20 mg kg(-1) sodium nitrite will form 20%
methemoglobin; however, in acute cyanide intoxication the associated s
evere bradycardia appears to limit the rate of absorption and thus the
rapid formation of methemoglobin, If the bradycardia is prevented or
reversed by atropine, the rate of absorption of sodium nitrite and the
formation of methemoglobin is able to reverse the otherwise lethal ef
fects of cyanide, Thus, an intramuscularly administered combination of
20 mg kg(-1) sodium nitrite and 1 mg kg(-1) atropine sulfate, rapidly
absorbed from the intramuscular site, appears to achieve the same deg
ree of effectiveness against acute cyanide intoxication as intramuscul
arly administered HH or DMAP, It would appear from these studies that
HH, DMAP and sodium nitrite with atropine are all potentially effectiv
e intramuscular antidotes for acute cyanide poisoning.