About Amyl Nitrate Treatment of Cyanide Poisoning

Systemic cyanide poisoning occurs from inhaling gaseous hydrogen cyanide, absorbing crystalline potassium cyanide or sodium cyanide through the skin or ingesting aqueous solutions of hydrogen cyanide or cyanide salts. The standard initial treatment for cyanide poisoning is amyl nitrate.

Administration

• Amyl nitrite is administered as a fast-acting vasodilator by inhalation. A capsule-like ampule filled with liquid amyl nitrite is crushed with the fingers to release the chemical's vapors and then held under the patient's nostrils for 15 to 30 seconds. This process is repeated at 1-minute intervals until sodium nitrite can be given intravenously.

Pharmacological Effects

• Amyl nitrite vapors are absorbed through the lungs. They begin relaxing the muscle of the heart within 1 minute. In addition, amyl nitrate triggers the production of methemoglobin, a specialized hemoglobin that delivers oxygen to tissues throughout the body. This substance also binds to the cyanide circulating in the system to form a nontoxic cyanide compound called cyanmethemoglobin.

Dosage

• Each ampule holds a volume of 0.3 ml and contains 98% liquid amyl nitrite. Up to 8 ampules may be used until intravenous sodium nitrite becomes available.

Side Effects

• Inhalation of amyl nitrite commonly produces facial flushing and light-headedness, sometimes accompanied with mild headache. However, some patients may experience nausea, vomiting, elevated heart rate, muscle weakness and involuntary incontinence.

Contraindications

• Amyl nitrate treatment should be carefully monitored in patients with glaucoma or a recent head injury. It is not known if amyl nitrate is harmful to a developing fetus.