Aluminum Phosphide; the Most Fatal Rodenticide and Fungicide

Introduction: Aluminum phosphide (AP) is a fumigate agent, which is also used to control rodents and pests in grain storage facilities. This agent is commonly used in low income and agricultural communities. AP is easily available, cheap and highly toxic. Ingestion of even half a fresh tablet invariably results in death. Its suicidal or accidental poisoning is a medical emergency, while in some low income countries it reaches to more than two third of poisoning deaths. Methods: PubMed was systematically searched (December 2006) for articles related to aluminium phosphide poisoning. 24 articles were finally included. Mechanism of action; AP on exposure to moisture, liberates highly toxic gas, phosphine. In animal and human models AP rapidly inhibits cytochrome-c oxidase leading to inhibition of mitochondrial oxidative phosphorylation and inhibits mitochondrial respiration and has cytotoxic action. Clinical Findings: Initial findings of intoxication may be nonspecific and transient. The symptoms may resolve within several hours after removal from exposure. It, however, produces phosphine gas, which is a mitochondrial poison. Its manufacturing and application pose risks of inhalation of phosphine. CNS; GCS is fine at the beginning. Biochemistry; Metabolic acidosis and liver dysfunction are reported. Shock is frequent. Respiratory Tract; Acute dyspnoea, hypotension, bradycardia and other signs of intoxication were also stated. Gastrointestinal; Reported short-segment esophageal strictures in the upper and mid esophagus, successfully managed by endoscopic dilatation. In sub-chronic use, degenerative changes in liver, heart and kidney of rabbits are reported. Cardiovascular; The ECG abnormalities are common and include hypotension, bradycardia, ST-T changes, Supraventricular tachycardia, ventricular ectopics, life threatening ventricular tachycardia, ventricular fibrillation, atrial flutter/fibrillation, variable degrees of heart block and toxic myocarditis. Haematologic; Chronic administration may lead to significant decreases in Na-K-ATPase activities in renal, hepatic and cardiac tissues, decreases of Ca-ATPase and Mg-ATPase in liver, and decreases in hematocrit, red blood cell count, hemoglobin and platelets. Prognosis: The mortality rate is high. The prognostic factors were shock, ECG abnormalities, using of vasoactive drugs, use of mechanical ventilation, and haemodynamic disturbances. Treatment: No specific antidote is known, but it is dose dependent and time dependent to stomach wash. In vitro, use of vegetable oils, coconut oil, and liquid paraffin and were effective in inhibiting release of phosphine from AP. Intravenous amiodarone/xylocard have successfully used to revert dangerous ventricular arrhythmias. Conclusion: Potential hazards associated with phosphide fumigants should be recognized. Minimizing the use of this fumigant improves worker safety, reduces both control costs and harm to the environment and potential duel use.(author)