Thankfully, the world of pain relief for our pets has come on leaps and bounds in recent years. With newer drugs and improved access to complementary treatments, such as physiotherapy and hydrotherapy, dogs with osteoarthritis can now enjoy even better quality of life. Grapiprant is one of these newer drugs. Of course it’s important that you understand any medicine you are giving to your dog. If you aren’t sure, ask your vet, who will be happy to answer any questions relating to your individual pet. In the meantime, let’s look at what we need to know about grapiprant.

What is grapiprant and what is grapiprant used for?

Grapiprant is a relatively new drug, used for treating osteoarthritis in dogs. It was approved in 2016 and has been available in the U.K. since 2019. It is a type of non-steroidal anti-inflammatory drug (NSAID).

NSAIDs have been around for a long time, but this is the first of its kind. It acts against pain, but with fewer side effects on the kidneys, liver and gut, when compared with most other NSAIDs. Having said that, other NSAIDs have also progressed to being more specific with fewer side effects, so there are plenty of options now.

How does grapiprant work?

Technically, grapiprant is a non-cyclooxygenase (COX)-inhibiting NSAID. Let’s explain this technical jargon! 

In osteoarthritis, the affected joints become inflamed and painful. Simply put, inflammation happens when a cell becomes damaged. This damage triggers a substance (an enzyme) called cyclooxygenase (or COX) to be activated. In turn, COX causes chemicals (prostaglandins) to be produced, which are involved in causing the redness, swelling, heat and pain associated with inflammation. This series of events is part of ‘the pain pathway’. So: Damage -> COX -> prostaglandins -> inflammation.

Most traditional NSAIDs work by blocking COX, so stopping the pain pathway quite early on. The downside to this is that all the prostaglandins are blocked. And some of these prostaglandins are important! There are many forms of prostaglandins, which have lots of other very important jobs, aside from inflammation. For example, they support blood flow, including to the kidneys, and help protect the stomach lining. 

Grapiprant works later on in the pathway, by blocking one specific prostaglandin which is involved in pain and inflammation. So it is a more targeted form of pain relief, with reduced side effects.

What are the possible side effects of grapiprant?

All medications can cause side effects, grapiprant included. The most common side effect reported is sickness, which can occur in more than 1 out of every 10 dogs treated. In many cases this is temporary, and the medication can be continued. However, in some cases it does continue, meaning a different medication would need to be used.

Other side effects include soft stools, diarrhoea and reduced appetite. These can happen in anywhere between 1 and 10 out of every 100 dogs treated. In very rare cases (less than 1 animal in 10,000 animals treated), sickness or diarrhoea with blood in have been reported. 

If you are concerned about any possible side effects of a medication your dog is taking, speak with your vet for advice.

Are there any risks to giving grapiprant?

Grapiprant should not be used in puppies under 9 months old, nor in dogs weighing less than 3.6kg. It also should not be used during pregnancy or lactation (nursing). This is because the safety of the drug has not been determined in these circumstances. 

Of course grapiprant shouldn’t be used in dogs with a known allergy to the medicine. However, it’s important to note that dogs who are sensitive to sulphonamide antibiotics may also react to grapiprant.

Grapiprant needs to be used cautiously in dogs with known liver, kidney, gut or heart disease.

If your dog falls into any of these categories, have a chat with your vet.

Can grapiprant be used with other medications?

Grapiprant should not be used alongside other NSAIDs. Similarly, using grapiprant straight after other NSAIDs could increase the likelihood of side effects, or make the side effects more severe. This means your vet would usually advise a ‘wash out period’ before starting grapiprant, where your pet would stop taking NSAIDs for a period of time. Of course this is based on your dog’s individual needs, so your vet is best placed to decide this.

It is not yet known whether grapiprant can be used alongside some of the common veterinary medications. These include some heart treatments, seizure treatments and behaviour-changing drugs. This means your vet may want to monitor your animal more closely if they decide to prescribe grapiprant alongside these drugs.

It’s important to let your vet know if your dog is taking any other medications or supplements, even over-the-counter or herbal ones. Remember, even these medications can interact – sometimes in unexpected ways – with medicines your vet has prescribed.
Sadly, osteoarthritis is a common source of long-term pain in dogs. Thankfully, there are lots of effective treatment options available these days. If you are worried that your dog may be in pain, book a check-up with your vet. If your vet prescribes grapiprant, or any other medication, it’s important that you understand what the drug is for, how to give it and what side effects to watch for. It can be useful to have a list of questions ready, or you may forget in the moment!

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