Questions to Help You Use Activated Charcoal Safely in Animals
The danger of hypernatremia is a definite worry when using activated charcoal as a treatment. To help you decrease the risk, consider these questions.
Q: Is the exposure serious and/or life threatening?
If the toxin is only going to cause mild clinical signs or signs that we generally are able to treat with medications in the hospital, then charcoal may not be necessary. If the toxin causes severe, difficult to treat signs or signs that are life-threatening, we may be more inclined to give charcoal.
Q: Are there alternative treatments/antidotes?
Do we have any other safe alternatives to charcoal? If emesis and/or the antidote is highly effective charcoal may not be necessary.
Q: Will the charcoal provide any benefit?
When the exposure occurred, how fast the toxin was absorbed, whether the toxin underwent enterohepatic recirculation: all these are questions we look at when deciding whether or not to use charcoal. And the most important question: Does the toxin even bind to charcoal?
Q: Is the pet stable enough for charcoal?
One of the big rules in toxicology is to treat the patient, not the toxin. A patient must be stabilized via standard methods before one even considers whether or not to give charcoal. Clinical signs such as depression, coma, seizure or loss of gag reflex are all signs that we would consider the pet a poor candidate for charcoal.
Q: Is the toxin likely to lead to aspiration or does patient exhibit clinical signs that would significantly increase the risk for aspiration?
There are many toxins—marijuana, baclofen and alcohol to name a few—that cause clinical signs (depression/coma, loss of gag reflex) that increase the risk for aspiration. If there is concern for aspiration, charcoal should not be given.
Q: Should I use sorbitol?
Judicious use of sorbitol is important. If charcoal stays in the GI tract too long it is possible it can release the toxin, thereby rendering the charcoal ineffective. Sorbitol is used to make sure charcoal is passed in a timely manner. Times to consider not using sorbitol include if a pet is dehydrated, currently having diarrhea or the toxin is likely to cause diarrhea. Otherwise, generally activated charcoal with sorbitol is recommended with the first dose (and once every 24 hours for repeated doses).
Q: Might the toxin cause ileus?
The longer activated charcoal sits in the GI tract, the longer it has a chance to pull fluid out of the body and into the GI tract, increasing the risk for hypernatremia. You may want to skip charcoal if the toxin is likely to cause a notable and/or prolonged ileus.
Q) Why does it happen?
A) It appears that charcoal pulls fluid from the body into the gastrointestinal tract, resulting in an elevation of the serum sodium.
Q) Does sorbitol have anything to do with it?
A) As a cathartic it is likely that it does, however we have seen cases of hypernatremia develop when charcoal without sorbitol is used.
Q) Does the patient’s size matter?
A) While it may be more likely for our smaller patients to develop hypernatremia, we have seen it in all sizes of dogs.
Q) Does it matter how much I give?
A) Definitely. Large doses do put animals at higher risk for developing hypernatremia, as well as repeating doses of charcoal.
Q) Can the toxin play a part in causing the hypernatremia?
A) Yes. Toxins that are osmotically active (pulling fluid towards them) such as paintballs or large ingestions of sugar, candy, or chocolate will increase the risk for hypernatremia. Other toxins that can affect the sodium, such as diuretics, can increase risk as well. Food items with high sodium content (salt, baking soda) would also increase the risk.
Q) Does it matter if my patient is dehydrated?
A) Yes. This can increase the risk for the hypernatremia to occur.
Q) When are signs visible?
A) Generally signs are seen within four hours of charcoal administration.
Q) What does it look like?
A) Common signs are ataxia, tremors and seizures (particularly those that don’t respond well to diazepam).
Q) How can you tell it’s hypernatremia?
A) This can be a tricky one, since there are a lot of toxins, like Bromethalin, that cause CNS signs that look like hypernatremia or vice versa. We advise checking sodium prior to giving charcoal for a baseline—or if the pet is already hypernatremic—and again within four hours if you have signs that are suspicious of hypernatremia. Remember sodium does not always have to be out of the normal range to cause signs; even a five-point jump is concerning.
Q) Are all species affected?
A) The cases we see are mainly in canines, however it is possible in cats and other species as well.