Piriton For Dogs: How Much? – View Dosage By Weight

So, your thinking can I give my dog antihistamine? Dog allergies are a lot more common than you think, but they don’t always require a trip to the vets and an expensive bill. Below we look at Piriton for dogs, and in particular the correct Piriton dosage for dogs

Are there side effects and is it safe to even use allergy tablets for dogs 

  • Can I give my dog Piriton?
  • Can you give a dog antihistamines?
  • Piriton dose for small dog?
  • Piriton dose for big dog?

You’d be amazed at how many dog owners have asked themselves these questions! We all have used this little tablet at some point or another, buts that’s us. What about Piriton for puppies and older dogs?

Well in this article we are not only going to find out. We dive in to see if Piriton tablets are safe for dogs and what dosage is best.

Let’s find out:

Humans can suffer from numerous allergies. It is estimated that each year, there is an increase in the amount of allergy suffers of 5%. A staggering number, we all must know someone who is stricken by streaming eyes, sneezing fits and a feeling of woe when the pollen count rises in summer.

So, I hear you ask, can I give my dog Piriton?

The short answer is YES you can.

Piriton is perfectly safe for dogs and is often recommended by vets as an alternative to prescription drugs to ease the symptoms for a dog, as long as the dosage is adhered to and the tablets or syrup are administered correctly in your dog.

Piriton can be used as a long-term solution for uncomfortable, chronic allergy symptoms and has the benefit of having few side effects.

There is no cure for allergic reactions for a dog, so the best course of action is to remove the offending allergen from the environment if at all possible. If your faithful friend has a reaction to your cleaning products for example, change them without hesitation. Unfortunately, for dogs suffering from hay fever type symptoms as a result of exposure to grasses and pollens, this can’t be avoided.

Dog owners can try to help alleviate some of the irritation by being aware of the causes and finding ways to offer some relief. This is where Piriton Tablets can help.

The symptoms are extremely miserable for the sufferer and, to counteract this, they usually take an antihistamine such as Piriton in either tablet or liquid form to alleviate the symptoms. 

Did you know that dogs can suffer from either mild or severe allergic reactions too?

It can be really uncomfortable for our four-legged friends too which begs the question

Can you use dog piriton?

Dog allergies and how you can help

An allergy is the enhanced reaction of the immune system to a particular substance that normally is not harmful to the majority. Cells within the blood are broken down and produce potent chemicals such as histamines to fight the invading substance. In fact, it is our immune system being over-zealous that causes the problem for both humans and our pets.

Some common allergens for dogs include:

  • Plant pollens, grasses, weeds, flowers
  • Mould spores
  • Food allergies
  • Dust Mites
  • Cigarette smoke (Another reason to stop)
  • Flea saliva (even one or two insect bites can cause a reaction)
  • Cleaning products
  • Pet dander (yes, dogs can be allergic to other pets in the household)
  • Fabrics, rubber and plastics
  • Perfumes or air fresheners

Some breeds are more susceptible than others to contracting allergic conditions which is why they need allergy relief. Although any breed can be affected, Sometimes, it can be an inherited problem and breeds such as Sharpeis, Shihtzus, Bulldogs, West Highland Terriers, Pugs, Boxers and Golden Retrievers are renowned for being pre-disposed to allergic skin conditions.

Symptoms indicating that your dog may have allergies:
  • Increased scratching
  • Upset stomach
  • Red, itchy and inflamed skin
  • Coughing and/or sneezing
  • Incessant chewing of paws
  • Irritated skin around eye or ear 
  • Swelling
  • Hair loss
  • Increased ear infections

What is Piriton?

Piriton contains chlorphenamine, which is a sedating antihistamine. Histamine is produced naturally in the body, but, when humans or dogs suffer from an allergy, large amounts of histamine are produced in an oversensitive reaction to a particular substance.

The reason behind this effect results from the immune system working overtime and that produces the irritating conditions.

Chlorphenamine works by blocking this reaction, reducing the risk of symptoms developing initially and relieving the itchiness associated with the condition.

Dog Piriton Side Effects

There are few side effects with this drug but watch out for the following in dogs:


Because Piriton contains a sedating antihistamine, your dog can appear drowsy so it’s important to ensure the dosage is absolutely correct, especially with smaller breeds of dogs.


As with any medication given to your dog, there is the chance that dogs body reacts in a different manner which can affect their bowel movements. Constipation is usually more common than diarrhoea in the case of Piriton, but that can differ. Any problems should sort themselves out after a couple of days, but, if the condition persists, make an appointment to see, or telephone your vet.

Dry Mouth

If your dog is drinking more than usual or smacking his lips, he is probably suffering from dry mouth (not producing enough saliva) which can be another side effect of using Piriton. Always ensure your dog has a plentiful supply of freshwater to satisfy any increased thirst. You could also try moistening dry food with stock or feeding bits of ice throughout the day to keep the dogs mouth moist.


Some dogs can experience nausea when using anti-histamines. This is usually only an initial reaction and quickly resolves itself but it can lead to loss of appetite or inability to keep food down. If this problem persists, stop using the drug and seek veterinary advice.

Changes in Behaviour

Most dogs suffering from an allergic reaction will be uncomfortable and may exhibit changes in behaviour becoming more aggressive or lethargic. Once you start using Piriton tablets if these changes continue or become worse it is a good idea to consult your vet as there may be another underlying problem.

The Correct Dosage and How Often?

Piriton, used as an allergy remedy for your dog or pet, is available in both tablet and liquid form. People often ask, is piriton safe for dogs? Whilst it is, it is important to check with your vet not only in order to administer the right dosage but also to check there will be no negative reactions with other medications.

Knowing how much piriton is vital. The tablets usually come in 4mg which is equivalent to 10ml of the syrup. Proper dosage depends on a number of different factors including the size, a dog’s body weight and breed of your dog and the severity of the reaction but in general, 1/2 a 4mg tablet or 5ml is prescribed for smaller breeds, while 1-2 tablets or 10-20ml of liquid can be administered to larger dogs. Make sure to always follow the instructions and seek advice so you don’t give the wrong dose.

This dose can be given up to three times daily if required. While Piriton tablets for dogs can be used in the long term, it is advisable to use only until the condition clears up or, in the case of seasonal allergies, as long as is needed.

“Ouch that Stings”

The tablets are especially useful if your pet or dog suffers from an allergic reaction to an insect bite. Some dogs seem to love chasing, and even eating wasps and bees in the summer, which can result in some nasty insect bites and stings.

While most only produce a mild annoyance to dog’s, some can cause a severe allergic reaction. Common signs to look for include redness and irritation around the bite on your dog or sudden swelling of the face, muzzle or mouth.

Piriton can provide almost instant relief in these situations and it is always a good idea to keep some handy in the summer months for emergencies.

Fleas, you want rid of these fast!

The most common cause of an allergic reaction in dogs is flea bites or insect bites it is the saliva they inject into the dog that causes the reaction with the dog’s skin becoming itchy and inflamed. The more the dog scratches only increases the problem and can result in hair loss issues and infection.

It is especially important to keep fleas under control with regular treatments for dogs. If they do succumb to the odd bite Piriton Tablets or liquid can ease the irritation before it causes further problems.

Where to buy?

Drugs that are prescribed for dogs are usually expensive so Piriton is a great alternative, especially for ongoing or long term allergy conditions with your dogs.

They can be bought over the counter in chemists and supermarkets or online in bulk for an even cheaper option.

It is advisable when buying the antihistamine or medication for your four-legged friend not to mention that fact to the chemist assistant.

How to Give Piriton to your Dog?

Because Piriton medication comes in both liquid and tablet form, it is easily administered to your dog. Both forms can be given with or without food.

The easiest way is to hide the tablet in a small amount of your pet’s favourite food. 

How much liquid Piriton to give a dog?

Alternatively, you can tilt the dog’s head back and place a spoonful of liquid or a piriton tablet on the back of the dog’s tongue, holding the mouth firmly shut until the animal has swallowed the full dosage.

If you forget a dose DO NOT double up on the next one.


Can you buy piriton over the counter?

Yes, Piriton comes in tablet form or syrup it relieves the symptoms of hay fever and allergies and can be purchased over the counter in pharmacies and supermarkets.

How long does it take for piriton to work?

You should notice some improvement within 24 hours of giving Piriton to your dog. Make sure you consult your vet for the correct dosage. You may notice your dog being a little drowsy at first but this is perfectly normal and nothing to worry about.

Is chlorpheniramine safe for dogs?

Chlorpheniramine is an antihistamine that is sometimes recommended by vets for pet itchiness and allergies. It is generally safe for use in dogs. However, there are some exceptions. If your dogs suffer from any of these conditions you should not use the drug.

  • heart disease
  • lung disease
  • glaucoma
  • prostate gland enlargement
  • high blood pressure

It can also interact with some other medications so it is important to discuss this with your vet before using the drug it is also not recommended for pregnant or nursing bitches.

Chlorpheniramine side effects?

When you use dog piriton you must be aware that it contains chlorpheniramine and although it is generally safe there are a few side effects to watch out for. These include loss of appetite, drowsiness, vomiting and diarrhoea

Can a dog overdose on Piriton?

Yes, that is why it is important to check the dosage before administering too much piriton. The recommended dose is usually 4 – 8mg over a period of 8-12 hours with the maximum level of 1.1mg/1lb for example a 20lb dog could be given 4mg but could have no more than 22mgs maximum over that period of time. Overdosing can cause severe reactions including seizures, so always consult with your vet before giving your dog Piriton

Can you use human Piriton?

Yes, you can, but it is important to use it under the guidance of your vet so you get the correct dosage as it can be different for humans and know what side effects to watch out for. Piriton can react adversely to certain medications especially barbiturates so do not use if your dog is taking other medication without talking to your local vet. Humans and dogs can obviously react differently so talk to your vet for advice if you’re unsure.

Dog Hayfever, can I give Piriton?

A lot of vets recommend dog piriton that suffer from allergies. Always check with your vet first as it is important to get the amount right and that depends on the weight of your dog. If you are given the go-ahead you should see some improvement within 24 hours, similar to what humans do.

Is it safe to give dogs Piriton when they’re on other meds?

No, Piriton can have serious reactions when taken with other drugs especially barbiturates so it is essential to discuss with your vet if your dog is on any other medication as it may not be suitable. As humans we wouldn’t take a cocktail of drugs, so neither should your animals.

Can I give a dog human anti-histamines?

Only some human anti-histamines are suitable for dogs Piriton can be used but it is always better to ask your local vet first as it might not be the best solution, you need to know the correct dosage, side effects to watch out for and it can be dangerous when combines with certain other drugs.


Watching your beloved dog suffer from the uncomfortable itching and soreness of allergies is heart-breaking and for many, the symptoms only get worse as dogs get older. It’s important to keep any dog healthy but even more so senior dogs,

Dog piriton can be safely used to relieve the discomfort and irritation of allergy symptoms without breaking the bank.

Furthermore, there is the added bonus of the antihistamine having little or no side effects. That said, before using any medication on your dog, it is essential that you consult with your vet first.

If the condition in your dogs doesn’t improve or becomes worse, seek medical attention immediately.

John Devlin

Hi, my name is John, and I am the founder of Dogsbarn – a UK-based website dedicated to helping the owners of furry friends enjoy life with their four-legged companion. We currently own two golden retrievers, George and Henry, who love running around in the park together. We are thinking about adding a third – called Frank! Our mission is to provide excellent guides and introduce great products we’ve bought or come across online.