Giving Dogs Piriton After an Adder Bite: How Much & How Safe?

adder bite dog piriton

Where I live, we’re in the warm weather adder season at the moment. This means the chances of my dog being bitten by this venomous snake has increased. However, I don’t wish to worry you, because the chances of a bite attack are quite slim. And even if a dog is bitten by an adder, fatalities are thankfully very rare, particularly with larger dogs.

Firstly though, when a dog is bitten by an adder, you should always seek professional veterinary help. Most cases will be treated quickly, with a full recovery expected. But did you know that most vets don’t carry adder antivenom?

Instead they rely on giving the dog fluids, steroids, plus the possibility antihistamines and antibiotics.

Please Note: that the following notes are for guidance only and you should always check with your own vet before letting your dog have Piriton for an adder bite.

Adder bite + dog + Piriton

Antihistamines are what I want to talk about today, in particular Piriton. If you look on the web, Piriton is said to be a fairly safe antihistamine for dogs and can help with adder bites. But what is the truth about its effectiveness and dosage levels?

I wanted to find out, so asked a vet about adder bites and dog’s having Piriton. Here’s what I discovered; plus, a roundup of what experts are saying online.

Handy Hint: If you suspect your dog has been bitten by an adder but didn’t see the attack occur, here’s a list of symptoms to check for.

What the experts say

The first consideration is whether dogs can take Piriton at all. Anne Threlfall of Davies the Veterinary Specialists, was interviewed by Country Living magazine recently, and said the following:

“The safest thing to say is that chlorphenamine (Piriton) can be administered to dogs, but this should be done under the direction of a veterinary surgeon. If you are concerned that your dog might have an allergy, please speak to your vet for advice. There are several different antihistamines used in dogs for a variety of different conditions. They are generally safe but should only be used as directed.” (view source)

The article went on to explain that chemists cannot legally sell a person Piriton if it is to be given to a dog. From a legal perspective, if you want to give your dog Piriton for an adder bite you would have to get it as a vet’s prescription. The over the counter Piriton is not licensed for animal use.

My take on this is that this ruling is there to safeguard not just the animal from being given too much, but also to protect people and organisations from legal action.

Anne Threlfall goes on to tell Country Living that:

“Some allergy medication, such as Piriton, can be administered to dogs. The indications and doses are, however, variable and therefore the medication should only be administered under the direction of your veterinary surgeon.” 

Piriton for dog adder bites

What can we take from this then?

Well, I found various instances online of not just experts, but also from dog owners saying that have given their dog Piriton after an adder bite, and then rushed the dog to the vets for a professional check-up.

dog adder bite piriton
Many dog owners will use Piriton after an adder bite.

For example, there’s a well-respected animal behaviourist I found online who said the following in a social media post about adder bites in dogs, and Piriton treatment:

“When walking the dogs, I always have a pack of Piriton. If an adder bit one of them I would give them a tablet and then get help from a vet ASAP. My local vet treats dog adder bites with steroid injections to get the swelling down, and then prescribes a 3-day course of antihistamine.” 

I also spoke to a professional dog walker on social media who said the following about giving dogs in her care Piriton after an adder bite.

“I’ve been unlucky enough to have dogs bitten by adders twice in the last five years. On both occasions I gave the dog a Piriton tablet and then drove them to the local vet clinic. Each time the vet has praised me for my actions, and then treated the dog who has made a full recovery. The vet has always said it’s good to carry this antihistamine around.”

And lastly, I read the following quote from a dog owner on a web forum:

“I always have Piriton in the kitchen and would give a dog bitten by an adder one tablet before driving them to the vest. Not all vet clinics will have antivenom, so it might be worth checking whether your local vet does. or where the nearest vet who does keep it is. There will be different reactions by different dogs, but the advice I’ve been given is to get a Piriton into the dog if possible and then get them to a vet quickly.”

Should you give your dog Piriton for adder bites?

I’ve not found anybody online cautioning against giving a dog Piriton for an adder bite, but that doesn’t mean it’s ok.

In fact, I read that it’s possible for dogs to overdose on Piriton.

Possible side effects

There are also possible side effects to be aware of, such as:

  • Vomiting and nausea.
  • Loss of appetite.
  • Constipation or diarrhoea.
  • Excessive thirst and dry mouth.
  • Behavioural changes including sleep disturbance or lethargy.

As with any medication, you don’t know how your dog will react to it. Dogs with pre-existing health conditions or other medication will be at a higher risk of a bad reaction.

The bottom line is this; you should not give your dog a dosage of Piriton for an adder bite without first asking your vet.

Dosage suggestions

The dosage amounts that various websites give on Piriton for dog bites all are reasonably consistent in their approach:

  • 2m to 4mg for a smaller dog bred (typically half to one Piriton tablet).
  • 4mg to 8mg for a larger dog breed (typically one to two Piriton tablets).

However, you still need to check with your vet first on what the correct dosage will be for your dog. Proper dosage levels will depend on the size, weight, and breed of your dog, plus their overall health and existing medications.

My assumption is that you need to be particularly careful on dosage with very small dogs, including toy breeds and puppies. Unfortunately, it’s also small dogs that are more at risk from a fatality after an adder bite.

Overdosing could result in a seizure, please talk with a vet first.


From what I’ve found, many dogs owners will give their dog Piriton, without talking to their vet first. However, I think you should always consult with a professional before giving your dog any type of medication.

The evidence is there that both vets and owners have been giving dogs Piriton antihistamine for over half a century.

So, to conclude, yes you can give a dog Piriton to help with adder bites, but please check with your own vet first.

And above all, if your dog has been bitten, get them to a vet immediately.

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Marc Aaron

I write about the things we've learned about owning dogs, the adventures we have, and any advice and tips we've picked up along the way.

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