Many of us enjoy a cheeky little festive drink (or two) around this time of year. And very often, with all the social gatherings, there tends to be a lot more alcohol around at home than usual – the sherry, the port, the Champagne or whisky on New Year’s Eve, and not forgetting the brandy for the Christmas pudding. All too often, we can become distracted with the haze of Christmas jobs to do. And remembering to keep things out of the reach of curious pets may get forgotten. Although toxicities associated with pets eating foodstuffs such as Christmas cake, chocolate and mince pies are much more common, we do see cases of alcohol toxicity in dogs, and occasionally cats, over the festive period, and beyond.
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Types of alcohol
When we talk about alcohol toxicity, we don’t just mean from alcoholic drinks or products containing alcoholic drinks. The main product in the alcohol that we drink is ethanol which can also be found in alcohol gel hand washes and in fermenting bread dough. Alcohol toxicity can also occur in pets that have ingested methanol, ethylene glycol – the main ingredient of anti-freeze windscreen washer fluids – or some topical anti-parasite treatments that contain isopropanol.
Why is alcohol toxic?
The mechanism by which alcohol can cause toxic effects is similar in all mammals. But the threshold level at which this toxicity occurs will vary greatly. The recognised lethal dose of ethanol for dogs is around 7-10ml/kg of 100% ethanol. Obviously, the percentage of ethanol in alcoholic drinks will be much lower than this. But some gel hand washes could contain up to 90% ethanol. The lethal oral dose of methanol is 4-8ml/kg but significant clinical signs can be seen at much lower doses. And for isopropanol, toxic effects can be seen at around 0.5ml/kg.
The most common way for an animal to be exposed to alcohol is through oral ingestion. But it can also be absorbed through the skin, such as is seen with dermal application of flea sprays. From this point, the alcohol is metabolised in the liver and the metabolites can have effects on the central nervous system, the liver and the heart.
Interestingly, most non-primate pets do not suffer the same potential for blindness and brain damage following methanol ingestion that primates (and humans) do, as they are able to safely eliminate the metabolite of methanol, formic acid.
Clinical signs of alcohol toxicity
Any clinical signs of alcohol toxicity will become evident within an hour of exposure and typically will include
- lack of coordination
- vomiting
- depression
- diarrhoea
- breathing difficulties
In the more severe cases, equally severe symptoms can be seen
- hypothermia
- seizures
- slow heart rate (bradycardia) or fast heart rate (tachycardia)
- low blood sugar (hypoglycaemia)
- low blood pressure (hypotension)
- coma
Unfortunately, a combination of some of these symptoms can bring about their own problems, for example, if an animal is depressed or lethargic, or even comatose, but then they vomit, it could lead to them aspirating the vomitus into their lungs.
In any suspicion of alcohol toxicity, contact a nearby vet.
Diagnosis of alcohol toxicity
Although it is possible to measure blood alcohol levels, tests are typically not readily available in primary practice so any results would be back after the patient is likely to have been treated. Diagnosis would usually be through a combination of relevant clinical history and supportive clinical signs.
Management of alcohol toxicity
The standard treatment for an orally ingested toxin tends to be decontamination (i.e. inducing vomiting to eliminate the toxin from the stomach), administration of activated charcoal then, if required, application of more specific therapies such as intravenous fluids or drugs.
For alcohol toxicity, induction of vomiting is only advisable if it’s within the first hour or so after ingestion and the animal is completely awake and aware, otherwise, as described above, there is an increased risk of them aspirating their stomach contents. There is also no evidence to suggest that activated charcoal has any benefit in reducing the toxic effects of the alcohol and is actually known to bind poorly with ethanol. Therefore, the only real treatment for alcohol toxicity is symptomatic and supportive care.
The use of intravenous fluids to correct any dehydration and maintain body fluid levels is always a good idea; as is monitoring and correcting any changes in body temperature, heart rate and blood pressure. Blood work can highlight a low blood sugar which in turn could lead to seizures and is one of the most serious side effects of alcohol toxicity.
For dermal exposure of isopropanol alcohol, the pet would need to be thoroughly washed to ensure any residual material is removed from their coat then symptomatic and supportive care continued as for oral ingestion.
Prognosis after alcohol toxicity
Prognosis is generally good after uncomplicated alcohol toxicity and most animals will recover within 12-24 hours. However, if there have been secondary issues such as seizures or aspiration of vomitus, further hospitalisation and treatment is likely to be required. The chance of long term effects following alcohol consumption is low.
Prevention of alcohol toxicity
The simplest way to avoid the risk of alcohol toxicity is to keep potential sources out of reach. As well as actual bottles of alcohol or alcoholic drinks, it is also important to be aware of other, less obvious, sources of alcohol as mentioned at the start, such as windscreen washer fluid and gel hand-wash. Food items that may contain alcohol should also be kept well out of the way as these tend to be as tempting to our pets as they are to us!
Beer for dogs?
People love sharing things with their pets and in the past decade, there has been a huge increase in human food and drink items marketed for pets. You can now get ice cream, chocolate and yes, even ‘alcohol’ for dogs and cats. Canine beer and feline wine don’t actually contain any alcohol. They are usually just a mix of flavourings, herbs and natural extracts. In themselves, they won’t tend to cause any harm to the animal but we just have to be aware of not creating a casual attitude towards the combination of alcohol and pets. Most people would just use them as a bit of occasional fun which is absolutely fine but, just like for ourselves, they need to be a treat and not an everyday occurrence.
Christmas is a time to eat, drink and be merry but the risk of overindulging tends to be at its highest. Temptation is all around but it’s important not to let your guard down, at least when it comes to our pets. Keep all food and drink out of reach, in cupboards or the fridge; be alert to unguarded buffets and keep pets out of the way when party guests come to visit. If you know that your dog or cat may have ingested alcohol or been exposed to other sources, it’s important to get them to the vet as soon as possible so any treatment that could be required can be started straight away. Don’t let their hangover give you a headache!
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