90 | The essential guide to toxicology part one: how to decontaminate poisoned pets as a vet nurse
In episode 90 of the Medical Nursing Podcast, we’re starting a brand new mini-series on toxicology.
Whether you work in general practice, referral medicine, or out of hours, you’ll encounter these patients often - and spoiler alert: our role is so much more than holding a litter tray under a patient whilst the apomorphine kicks in.
Our role in managing toxin ingestion cases is vast, whether that involves providing advice to caregivers who are concerned, monitoring a patient exhibiting active signs of toxicity, or managing critically ill patients on CRIs or receiving ventilation.
And with all of this, of course, there are tons of practical skills we get to use in the process.
To start things off, this episode will give you all the information you need on toxicology triage and decontamination. We’ll chat through pre-visit advice and how to get the information you need from your caregivers, when these patients should be seen, and what decontamination strategies we have (as well as which toxins to use them with).
You’ll leave the episode feeling ready to triage and stabilise your toxicity cases - and then across the next few weeks, we’ll take a closer look at the specific toxins commonly affecting our patients.
Let’s start with the role of the veterinary nurse in toxicology cases.
It sounds obvious, but we’re generally the first people dealing with these patients. We’re the ones picking up the phone out of hours, or the ones our reception team speak to for advice, or the ones triaging the patient who has just arrived as an emergency.
We’re the ones who need to ask the right questions (and know which questions are the right ones in the first place), and we’re often the ones tasked with decontaminating our patients. And that’s great, because we can - and should! - be utilised to do just that.
However, before we consider decontamination and stabilisation, we need to understand what our patient has been exposed to, assess their level of exposure, and determine how recently they were exposed.
What questions should we ask clients if we think their pet has eaten something?
When a caregiver calls and says, ‘I think my dog just ate something’ our main goals are:
To understand what active ingredients/toxins our patient has been exposed to
To identify the patient’s condition right now (and whether that has changed)
To provide clear guidance on next steps
And to do all of this as quickly as possible.
Once you’ve got an idea of the patient’s current status, we need to know:
Brand names, ingredients and active agents of anything ingested (get them to take a photo of the packaging if possible)
The patient’s size/weight (or a rough estimate) so that we can estimate a mg/kg dose ingested
When the substance was ingested
The patient’s signalment
Any significant disease history (eg kidney disease or liver disease that could impact metabolism and elimination of the toxin)
The clinical signs present (if any are currently) and how these have progressed
Whether the patient has vomited
If there have been any changes to their behaviour, and if so, what
We also need to understand if the caregivers have tried any remedies at home. For example, anything they may have given to try to induce emesis, milk, bread, or any other common myths or misconceptions they may have read online. If that’s the case, this can alter gastric content, complicate decontamination, and in some cases cause further problems.
If a caregiver asks what can be done at home, it’s usually best to advise that the patient comes straight to the clinic for decontamination by the veterinary team.
And while they’re en route, we’ll be the ones preparing emergency equipment, calculating toxic doses (if not already done) and getting ready to triage them on arrival.
What should the veterinary nurse look out for during toxicology triage?
On presentation, our priority is to assess whether the patient is a candidate for decontamination - and if so, how to best decontaminate them.
Like any emergency patient, our triage assessment begins with a focused primary survey or evaluation of the major body systems: the cardiovascular system, respiratory system, and neurological system.
If the patient is seizuring, obtunded, collapsed, or vomiting uncontrollably, they are not a candidate for emesis induction and instead need stabilisation (or GA and gastric lavage, depending on the individual case, toxin, and the veterinary surgeon’s plan).
For stable, asymptomatic patients who have recently ingested a toxin (eg within the last 1-2 hours), decontamination is often both appropriate and effective. But timing, toxin characteristics, and the individual patient factors all need to be taken into account.
For example, lipid-soluble drugs or sustained-release medication formulations of medications may still be present in the stomach several hours later. However, rapidly absorbed water-soluble toxins may no longer be present after just 30 minutes.
How do we decontaminate poisoning cases, and which do we use when?
There are several ways to decontaminate a patient after toxin exposure; these are generally divided into gastrointestinal decontamination (for ingested toxins) and dermatological decontamination (for contact exposure with toxins).
Let’s start by looking at induced emesis.
The most common type of gastrointestinal decontamination is induced emesis. This is the one we’ve probably all done, with varying levels of success, depending on when our patient ate their illegal snack.
Induced emesis is best done within 60-90 minutes of ingestion but may be appropriate up to 2-3 hours in certain cases, depending on the toxin and the patient’s gastric motility.
In dogs, apomorphine is the gold standard treatment for inducing emesis. It can be administered IV for a rapid onset or via the conjunctival sac for more gradual absorption. Apomorphine works by stimulating dopamine receptors in the chemoreceptor trigger zone (CRTZ), a region in the brainstem which directly detects toxins in blood and CSF and induces vomiting to eliminate them.
This drug induces vomiting within minutes, but can cause lethargy and protracted vomiting and nausea. Some dogs may require a second dose if their initial treatment is unsuccessful, and many patients require antiemetics such as maropitant after decontamination.
In cats, apomorphine is unreliable and can cause paradoxical excitation. Instead, dexmedetomidine is often used, usually IM or IV. Success rates are variable and often lower than in dogs; however, vomiting typically occurs within 5-10 minutes after injection. The main side effect, perhaps unsurprisingly, is sedation - reversal with atipamezole is generally performed after decontamination is complete.
Emesis is contraindicated in patients who have ingested caustic agents or harmful substances (e.g. batteries, bleach, oven cleaner, petrol, lighter fluid, etc), or in those who are seizuring, collapsed, or cannot protect their own airway.
The next step in managing ingested toxins is the use of activated charcoal.
I used to think that activated charcoal was the magical cure for every toxicity case, but it’s only effective against certain toxins - many substances do not bind to it. In fact, activated charcoal is ineffective against xylitol, ethanol, ethylene glycol, heavy metals, and most inorganic substances.
When activated charcoal is used, it should ideally be given within an hour of ingestion, after successful emesis. It can also be used as a standalone option if we’ve missed the window of emesis, and generally multiple doses of activated charcoal are needed - especially for drugs with enterohepatic recirculation like theobromine and certain medications (eg NSAIDs).
Activated charcoal should be administered slowly, carefully, and ideally via a feeding tube if using a liquid formulation, to minimise the risk of regurgitation and aspiration. Alternatively, charcoal gels are now available, allowing larger doses to be administered with smaller volumes. It should not be given if the patient is not fully conscious or cannot swallow effectively.
What about gastric lavage? When do we perform this?
Gastric lavage is reserved for unconscious or anaesthetised patients who cannot vomit and have ingested a significant (ie toxic/life-threatening) dose which we need to clear ASAP.
To perform gastric lavage, the patient is anaesthetised and intubated with a cuffed ET tube to protect the airway. An orogastric tube is passed, and the stomach is lavaged with small volumes of water repeatedly until the returning gastric content runs clear.
If appropriate (depending on the toxin), activated charcoal can then be administered directly into the stomach before the patient recovers from anaesthesia.
As anaesthesia is required to perform gastric lavage safely, this may not be appropriate in all patients, for example, those who are not stable enough to undergo anaesthesia.
How does topical decontamination differ, and how do we perform this as veterinary nurses?
Contact exposure to toxins such as permethrin, essential oils, or other substances, requires topical decontamination.
Depending on the area affected, the patient should be bathed using a mild detergent and warm water to remove as much residue from the skin/coat as possible (whilst avoiding abrasive scrubbing or harsh shampoos/chemicals which could irritate the skin further).
If the patient has had ocular exposure, the eye should be copiously flushed with sterile saline or water. An ophthalmic exam should then be performed (eg looking for evidence of corneal ulceration or other abnormalities) and lubricating or medicated eye drops administered as needed.
Preventing patients from ingesting any topical toxin is also essential. Elizabethan collars should be placed to prevent patients from grooming their contaminated coat.
What about after decontamination? What are our next steps when managing veterinary toxicology cases?
After successful decontamination (or if we’ve determined that decontamination isn’t appropriate), our next priority is careful monitoring.
Depending on the type of toxin ingested, patients will often require treatment and intensive monitoring, including:
IV fluid therapy
ECG monitoring
Blood pressure checks
Glucose monitoring
Temperature monitoring and regulation
Neurological observation and seizure management.
As nurses and technicians, our job is to keep a close eye on the patient, spot subtle signs of deterioration, and be prepared and ready to intervene if we see things like seizures, tremors, or changes to the patient’s cardiovascular stability.
We’re also often responsible for liaising with poison information services or helplines, and seeking advice for our caregivers and vets. And in many cases, we’re the ones calculating toxic doses and advising vets of this information so that they can quickly plan next steps.
Client education is another big area where nurses and technicians play a vital role. We explain what we’re doing and why, set expectations for hospitalisation and recovery, support caregivers through what is often a very stressful time, and advise on preventing future exposure.
Our role in managing these patients is vast, and whilst it begins with thorough decontamination, there’s a lot more to it than that - which we’ll look at in depth across the rest of this series.
So there you have it! An introduction to toxicology and the essential information you need to decontaminate your patients confidently. I hope this has given you a bit of a refresher and left you feeling ready to tackle your next toxin case.
Did you enjoy this episode? If so, I’d love to hear what you think. Take a screenshot and tag me on Instagram (@vetinternalmedicinenursing) so I can give you a shout-out and share it with a colleague who’d find it helpful!
Thanks for learning with me this week, and I’ll see you next time!
References and Further Reading
Boothe, DM. 2012. Veterinary Pharmacology and Therapeutics. Wiley-Blackwell.
Gupta, RC. 2025. Veterinary Toxicology: Basic and Clinical Principles. 4th edition. Elsevier.
King, L. & Boag, A. 2018. BSAVA Manual of Canine and Feline Emergency and Critical Care, 3rd edition. British Small Animal Veterinary Association.
Maxwell, KM. et al. 2024. Use of orally administered dexmedetomidine to induce emesis in cats. Journal of Feline Medicine and Surgery, 26(5).
Peterson, ME. & Talcott, PA. 2013. Small Animal Toxicology, 3rd edition. Saunders Elsevier.
Schmid, RD. & Brutlag, A. 2024. Principles of toxicosis treatment in animals [Online] MSD Veterinary Manual. Available from: https://www.msdvetmanual.com/toxicology/toxicology-introduction/principles-of-toxicosis-treatment-in-animals
Silverstein, DC. & Hopper, K. 2015. Small Animal Critical Care Medicine, 2nd edition. Saunders.
Stern, L. 2025. Algorithm for When and How to Induce Emesis in Small Animals After Toxin Ingestion [Online] Today’s Veterinary Practice. Available from: https://todaysveterinarypractice.com/toxicology/algorithm-for-emesis-in-small-animals/
Veterinary Poisons Information Service, 2023. Emesis in the management of poisoning [Online] VPIS. Available from: https://www.vpisglobal.com/vpis-position-statements/emesis-in-the-management-of-poisoning/
Walmsley, D. & Bray, J. 2019. Apomorphine hydrochloride: a clinical review with retrospective analysis of use in 1126 dogs treated in emergency practice. Companion Animal, 24(8), pp. 419-425.
