Appropriate decontamination procedures are often paramount to successful treatment and are typically the first approach that should be considered in most intoxication cases (see When & How to Decontaminate the GI Tract) in which the patient was exposed to a toxic dose. The decision to decontaminate is based on time since exposure, specific toxicant, dosage, and presentation and signalment of the patient; methodology depends on the route of exposure. In some cases, decontamination is contraindicated (eg, emesis induction when a caustic agent was ingested, administration of activated charcoal to a hypernatremic patient), as it may worsen prognosis or clinical signs.3
GI decontamination is the most common procedure because most cases involve ingestion of toxic substances.
In general, emesis induction should be performed within 30 to 60 minutes of substance ingestion for maximum effect; however, for certain substances (eg, chocolate, grapes/raisins), emesis induction several hours postingestion can be beneficial. Emesis induction should only be performed in clinically unaffected patients and is contraindicated in patients with subtoxic ingestion, neurologic impairment (due to increased risk for aspiration), and ingestion of certain toxicants (eg, volatile hydrocarbons [eg, gasoline]). Likewise, extra care should be taken if the ingested toxicant may result in rapid-onset clinical signs (eg, xylitol inducing hypoglycemia in dogs, antidepressant or attention deficit hyperactivity disorder medications resulting in CNS signs). If spontaneous emesis has already occurred, the need for forced emesis induction should be carefully considered. If the patient has vomited or shows clinical signs of intoxication, gastric lavage may still be effective after the patient is stabilized if the ingestion was recent (ie, <60 minutes prior to presentation), a large amount of substance was ingested and is still located within the stomach, or the ingested substance (eg, tricyclic antidepressants) results in delayed gastric emptying. Selecting the correct emetic agent for the species is also important (see Emetic Agents for Cats vs Dogs).
If the toxicant binds to charcoal, activated charcoal (1-3 g/kg PO) with a cathartic (eg, sorbitol) may also be administered to adsorb toxicants and accelerate GI transit time.4 If the ingested toxicant undergoes enterohepatic recirculation (eg, bromethalin) or is a sustained-release formula, multiple doses of activated charcoal (1-2 g/kg without a cathartic every 6-8 hours for 24 hours) may be beneficial. The most common adverse effect is hypernatremia; thus, concurrent administration of IV fluids and monitoring of serum sodium concentrations is advised.
In patients with ocular exposure, the eyes should be flushed ideally with eye wash solution or warm tap water (saline can also be used if needed). To remove topical toxicants (eg, essential oils, concentrated pyrethroid products in cats), the patient should be bathed with a follicle-flushing or degreasing shampoo5; dishwashing liquid will also suffice.