The object of this study was to evaluate the effectiveness of five regimens in treating
cyanide poisoning. A series of anesthetized adult beagle dogs were instrumented to record hemodynamic and respiratory function and given 2.5 mg/kg
sodium cyanide intravenously. The 10 control animals given only
cyanide died at from 5 to 7 minutes.
Therapy, as described below, was given to other groups at from 2 to 3 minutes following the
cyanide administration.
Artificial respiration did not alter the lethal effects of
cyanide nor prolong survival time in any of the 10 animals.
Amyl nitrite given by inhalation or by the intravenous route allowed survival of all 15 animals.
Sodium nitrite (20 mg/kg), dimethylaminophenol (DMAP) (5 mg/kg), and
hydroxylamine hydrochloride (5 mg/kg) given intravenously with no artificial ventilation also allowed for 100% survival (15 animals).
Amyl nitrite,
sodium nitrite, and
sodium thiosulfate were ineffective when given intramuscularly (I.M.) (0 of 12 dogs); however, I.M. DMAP (5 mg/kg) and I.M.
hydroxylamine hydrochloride (50 mg/kg) increased heart rate and blood pressure and restored spontaneous breathing. All 15 animals treated with I.M. doses of either of these drugs survived the lethal dose of
cyanide. Results of these studies indicate that intravenous
sodium nitrite, DMAP, and
hydroxylamine hydrochloride, and
amyl nitrite by inhalation, are all effective in reversing the lethal effects of
cyanide poisoning. Only DMAP and
hydroxylamine hydrochloride are effective when given by the intramuscular route. These results provide data to support an approach to
therapy that is more practical and applicable where expert medical care may not be available following
cyanide exposure.