Can I Give My Dog Piriton For Allergies? Side Effects & Dosage

If your furry friend has allergies or has had a reaction to something, you have likely wondered if you can give your dog Piriton?

As with all medications traditionally made for humans, it’s important to exercise caution when considering this as dogs simply don’t process consumables the same way we do and often need unique, dog-specific drugs.

But what about Piriton? Can you give this to your pup?

Piriton is an antihistamine that makes use of something called chlorpheniramine maleate, a sedating antihistamine.

It works by preventing a substance in the body called histamine from responding negatively to an allergen, which then leads to a series of events that put the immune system into overdrive.

We recognize the results of this chain of events as allergic reactions. The chlorpheniramine in Piriton stops this reaction from taking place.

Quick Answer: Unlike most human medications, Piriton is actually pretty canine-safe and can be used for your Dog (when directed by a vet). It is widely used by vets in the UK and is prescribed as an alternative to other varieties of prescription drugs for dogs with allergies to reduce the severity of symptoms.

What Symptoms Can Piriton Be Used For?

Piriton is given to dogs with the following symptoms:

  • Allergies
  • Scratching
  • Itchiness
  • Eye irritation
  • A runny nose
  • Hay fever
  • Insect Bites
  • Dust mite hypersensitivity
  • Bee stings
  • Fleas
  • Anxiety

For many dogs, Piriton isn’t just a temporary or seasonal drug, but a long-term way to combat the symptoms of chronic allergies without too many side effects in tow.

Since there’s no real cure for allergies, it’s no surprise that some canines have to turn to use antihistamines regularly as part of their medications.

Piriton can offer relief to these annoying and often overwhelming symptoms. You can find Piriton in both liquid and tablet varieties. If Piriton does not work for your dog or if they have a bad reaction to it, you can discuss alternative medications with your vet.

Can I Give My Dog Piriton?

As a rule, you should never give your dog Piriton without prior discussion with a veterinarian. Although it’s usually safe, getting the dosage wrong or trying to treat the wrong condition with it can have highly negative results.

In addition, if your dog is on other medications, there is a risk of the Piriton mixing poorly with another drug. As such, the safest play is to only administer Piriton when your vet has specifically prescribed it.

It’s important to follow all the instructions your vet provides when you are giving Piriton to your dog, especially when it comes to administering a safe and effective dosage.

Depending on your dog’s unique condition, weight, and age, a vet will prescribe different doses. For example, a dog who experiences itchiness now and then won’t get as high a dose as one with hay fever.

The typical dose prescribed to most dogs is between 0.2 to 0.8 mg of Piriton tablets per kg of their body weight, typically once every 8 to 12 hours or up to three times daily.

Keep in mind that all dogs react to medications and consumables differently. Your dog may develop an adverse reaction to Piriton or its active ingredient, and this can lead to potentially fatal consequences.

This is why you should always monitor your dog shortly after their first dose of Piriton.

If you notice that they begin to experience problems such as fluid retention, constant, frequent vomiting, pain, swelling or issues with vision, immediately stop administering the drug and speak to your vet as soon as possible.

What Are the Side Effects of Piriton For Dogs?

Unfortunately, no drug is without its side effects. If your dog is on Piriton, they may experience some unpleasant side effects, especially as Piriton is a sedating antihistamine. Here are some side effects that may occur.

Nausea Or Vomiting

This is the main side effect that you will probably notice if your dog begins taking Piriton.

Usually, this reaction goes away fairly quickly, but do note that in the meantime, your dog may not have as strong an appetite as usual. If vomiting does not stop, speak to your vet.

Constipation Or Diarrhoea

This antihistamine can have an effect on a dog’s bowel movements and digestive system. In most cases, it’s constipation and not diarrhoea that happens as a result of Piriton consumption.

Make sure to observe and monitor your dog when they go to the bathroom after consuming Piriton. Small, dry stools or straining with no stools being eliminated point to constipation. Once again, this should go away fairly quickly, but if it doesn’t, speak to your vet.

Thirst Or Dry Mouth

Occasionally, Piriton causes the salivary glands to produce less saliva than necessary, which causes a dog’s mouth to be overly dry.

A pup who repeatedly closes and opens their mouth or smacks their lips in an unusual way could be experiencing dry mouth.

A dog on Piriton may also, therefore, appear thirstier, so you will notice them drinking more water than usual. Make sure to replenish their water bowl when needed.


Again, we are dealing with an antihistamine with sedative properties, so it would be no surprise if your dog seems drowsy or sleepy after consuming some.

This may also cause a dog to feel less sleepy at night. To avoid potentially severe negative effects, adhere to all dosage requirements and instructions given by your vet.

Notice Any Behavioural Changes?

It’s not uncommon for a dog to become more aggressive or appear lethargic when experiencing other side effects from this drug. Your dog’s behaviour should revert to normal in a few days. Speak to a vet if it does not.

Before giving your Dog Piriton, we strongly advise you to seek the advice of a qualified veterinarian beforehand. This same advice applies to other sorts of medication such as paracetamol or aspirin.

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