Salicylate Toxicity

Abstract

Multiple forms of salicylates exist; the most commonly encountered is acetylsalicylic acid, brand name Aspirin.All salicylates are non-steroidal anti-inflammatory drugs meaning they inhibit the enzyme cyclooxygenase (COX).COX inhibition ultimately inhibits prostaglandin formation which mediate inflammation and fever.They do, however, possess unique properties that are of consequence in toxicity which will be reviewed here.Salicylates destroy the proton gradient in mitochondria used to generate ATP.Clinically this manifests as metabolic acidosis and hyperthermia.Salicylates also directly stimulate the respiratory center of the brain leading to a primary respiratory alkalosis.Clinically this presents as tachypnea and given the concurrent metabolic acidosis produces the classic ABG finding of a mixed respiratory alkalosis and metabolic acidosis.Adult Respiratory Distress Syndrome (ARDS) and cerebral edema also occur and portend a poor prognosis.Both acute and chronic toxicity occur the main difference being the more insidious onset in chronic and the associated lower serum salicylate concentrations.Chronic toxicity often occurs with repeated supratherapeutic doses of aspirin when being used to treat chronic conditions such as arthritis.