Cyanide poisoning is treated by
(A) Sodium thiosulphate + Sodium nitrate # Treatment should be started immediately. The principle of the treatment is to reverse the cyanide-cytochrome combination. This is achieved by converting haemoglobin to methaemoglobin by giving nitrites. Break 0.2 c.c ampoule of amyl nitrite in a handkerchief and hold over the patient's nose for 15 to 30 seconds of every minute. 0.3 g. of sodium nitrite in 10 ml. of sterile water is given i.v. slowly, over a period of two to three minutes. Sodium nitrite forms methaemoglobin (Hb-Fe2+), then competeswith cytochrome oxidase for the cyanide ion, thusprotecting cytochrome oxidase. Do not remove theneedle. Through the same needle infuse 25 g. of sodium thiosulphate in 15% solution, i.v. over a period often minutes. It converts cyanide to non-toxic thiocyanate, which is excreted in urine.Repeat the nitrite-thiosulphate injection after an hour if recovery has not occurred. Hydroxocobalamine (Vitamin B12) 4 g. i.v. as infusion is given. It detoxifies cyanide by giving a hydroxyl group and then binding a cyanyl group from the cyanide, forming non-toxic cyanocobalamine which is excreted in the urine. It may be used with sodium thiosulphate which reacts with cyanocobalamine in the presence of the enzyme rhodanase, to produce thiocyanate. Dicobal EDTA acts by chelating cyanide to form a harmless product that is excreted in the urine. 600 mg. is given i.v. slowly. It is followed by 300 mg. if recovery does not occur. Cobalt EDTA and aminophenols are more rapid in action, efficacious, and less toxic than nitrites. 4-dimethylaminophenol (4-DMAP) 3 mg/kg. i.v. Gastric lavage is then performed on those who have ingested cyanide using activated charcoal, a mixture of 6% sodium carbonate, 15% ferrous sulphate and 3% citric acid, or 3% hydrogen peroxide, or 5 to 10% sodium thiosulphate, or 1:5000 potassium permanganate, and 200 ml. is left in the stomach. Alternatively stomach wash can be done with a mixture of sodium bicarbonate and ferrous and ferric chloride. Methylene blue is not effective. Ventilate with hundred percent oxygen. Methaemoglobin of more than fifty percent is an indication for exchange transfusion or administration of blood. If death is delayed, a mixture of ferrous and ferric sulphate with potassium carbonate may be given as a chemical antidote to form Prussian blue. Keep the airway clear. Patient should be kept under observation for 24 to 48 hours, as cyanide toxicity may recur. In poisoning by inhalation, remove the patient at once to fresh air and start artificial respiration and oxygen.
Sodium thiosulphate + Sodium nitrate
Methylene blue
Sodium thiosulphate only
Sodium nitrate only
Misc.