The recommended dose of activated charcoal in small animals is 1 to 5 g/kg of body weight orally.2,5 As specific brands vary in their concentration of activated charcoal, this calculated dose is recommended.2,5 A one-time dose of an osmotic cathartic—most commonly sorbitol—given concurrently with the activated charcoal or within
30 minutes of giving the activated charcoal is recommended (see the sidebar "When to add a cathartic" on the last page of this article).2,5 Also see the sidebar "Should activated charcoal be given with or without food?"
Should activated charcoal be given with or without food?
Multiple doses of activated charcoal are indicated when the toxicant is a delayed release product, if it undergoes enterohepatic
recirculation, or if it has a particularly long half-life (e.g. naproxen in dogs).5 When giving multiple doses of activated charcoal, only the first dose should contain a cathartic. Dosing is 1 to 2 g/kg
orally every four to six hours for three to four doses, depending on how the patient is doing.
Activated charcoal administration is contraindicated for a patient that is already exhibiting clinical signs (e.g. tremoring, agitated), as that means the poison has already been potentially absorbed.
Another contraindication for administration of activated charcoal is when it does not bind to the toxicant (e.g. small organic molecules, alcohols, or heavy metals). For example, activated charcoal administration is not indicated for
toxicants such as ethanol, ethylene glycol, xylitol, heavy metals (e.g. ferrous sulfate, iron, zinc, lithium), nitrates, sodium chloride, and chlorates.1,2,5
When the time frame for the beneficial effects from activated charcoal has passed (typically > 1 hour), it is contraindicated
to administer activated charcoal, except under certain situations previously mentioned (see "Multiple doses" above).2,5
Activated charcoal administration is also contraindicated
> With the ingestion of certain toxicants, including corrosive agents, caustic agents, or hydrocarbons, because of a lack of
> With salt toxicosis (e.g. ingesting homemade play dough, table salt, paint balls) because of the potential to contribute to or worsen hypernatremia,
> Pending advanced diagnostic tests (e.g. endoscopy, surgery), which may result in an obstruction of the field of view.2,5
See Table 2 for additional contraindications for activated charcoal administration.
Contraindications for activated charcoal administration*