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Poison proofing your home against aspirin

Salicylates are ubiquitous agents found in hundreds of over-the-counter (OTC) medications and in numerous prescription drugs, making overdose very easy.  Its presence is often not realised.  Cold remedies, pain relief, hangover remedies all contain aspirin.  The chemical is odourless and is soluble in water. You would never guess it was there.

Salicylate ingestion continues to be a common cause of poisoning in children and adolescents for this reason. The prevalence of aspirin-containing analgesic products makes these agents, found in virtually every household, common sources of death. ‘Percy Medicine’, for example, contains bismuth subsalicylate as the active ingredient and is used as a constipation reliever. A case of neonatal salicylate poisoning due to administration of this medicine as a colic reliever has been reported. Percy Medicine is available OTC.

More than 10,000 tons of aspirin are consumed in the United States each year. Aspirin or aspirin-equivalent preparations (in milligrams) include children's aspirin (80-mg tablets with 36 tablets per bottle), adult aspirin (325-mg tablets), methyl salicylate (eg, oil of wintergreen; 98% salicylate), and Pepto-Bismol (236 mg of nonaspirin salicylate per 15 mL).

Ingestion of topical products containing salicylates, such as Ben-Gay, salicylic acid (keratolytic), and oil of wintergreen or methyl salicylate, can cause severe salicylate toxicity. One teaspoon of 98% methyl salicylate contains 7000 mg of salicylate, the equivalent of nearly 90 baby aspirins and more than 4 times the potentially toxic dose for a child who weighs 10 kg. Salicylate toxicity has been reported with the topical use of salicylate-containing teething gels in infants.

A comprehensive review of the existing medical literature on methyl salicylate poisoning has determined that it is a relatively common source of pediatric exposures. In younger children, most of these exposures are accidental. Intentional ingestions are much more common in adolescents.

The prevalence of alternative medicines and the popularity of herbs and traditional medicine formulae are increasing in North America. Many of these medicines may contain salicylate.

Phases and symptoms of salicylate toxicity

Nausea, vomiting, diaphoresis, and tinnitus are the earliest signs and symptoms of salicylate toxicity. Other early symptoms and signs are vertigo, hyperventilation, tachycardia, and hyperactivity. As toxicity progresses, agitation, delirium, hallucinations, convulsions, lethargy, and stupor may occur. Hyperthermia is an indication of severe toxicity, especially in young children.

The acid-base, fluid, and electrolyte abnormalities seen with salicylate toxicity can be grouped into phases.

Phase 1 of the toxicity is characterized by hyperventilation resulting from direct respiratory center stimulation, leading to respiratory alkalosis and compensatory alkaluria. Potassium and sodium bicarbonate are excreted in the urine. This phase may last as long as 12 hours.

In phase 2, paradoxic aciduria in the presence of continued respiratory alkalosis occurs when sufficient potassium has been lost from the kidneys. This phase may begin within hours and may last 12-24 hours.

Phase 3 includes dehydration, hypokalemia, and progressive metabolic acidosis. This phase may begin 4-6 hours after ingestion in a young infant or 24 hours or more after ingestion in an adolescent or adult.

Patient education

Advise patients and their families that use or overuse of seemingly benign OTC medications is sometimes dangerous. The ready availability of aspirin and aspirin-containing products does not establish the safety of aspirin.