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Carprofen is the anti-inflammatory I reach for more than any other in dogs. It takes the edge off arthritis and it covers a dog through the first days after surgery. The dose is 2 to 4 mg/kg a day, and most of what goes wrong with this drug comes down to the dose, the dog it was given to, or a second medication nobody mentioned.
Key Takeaways
Stop the carprofen and call us if: your dog passes black tarry stool or vomits blood, the gums or whites of the eyes look yellow, they stop eating, or they go suddenly weak.1,2 (519) 896-0532, or our emergency page after hours.
Carprofen is a prescription non-steroidal anti-inflammatory drug for dogs. You'll see it as Rimadyl, Vetprofen, or generic carprofen.
It acts on the cyclooxygenase enzymes, COX-1 and COX-2, which build the prostaglandins behind swelling and pain. COX-1 also protects the stomach lining and helps maintain blood flow through the kidneys. COX-2 does most of the inflammation work.
Carprofen leans on COX-2, by roughly 7 to 17 fold in canine whole blood.3 That preference is why it's gentler on the stomach than aspirin. It still touches COX-1 though, which is why stomach upset is the most common complaint we hear. The half-life in dogs is around 8 hours, so once-daily dosing works because the anti-inflammatory effect outlasts the blood levels.3
Never give a dog a human anti-inflammatory. Ibuprofen and naproxen cause ulceration and kidney injury at doses people take without thinking, and our page on ibuprofen toxicity in dogs covers what to do if it's already happened.
What it doesn't do is tell you why your dog is sore. If a dog turns up suddenly lame I want a diagnosis before a prescription, because sudden limping on a back leg has a few causes that get worse if you mask the pain and let the dog keep loading the leg.
The starting dose is 2 to 4 mg/kg per day, given either as one dose or split into two equal doses. Depending on how your dog responds, that can usually be reduced after seven days to 2 mg/kg once daily.1
| Dog's weight | Low end (2 mg/kg/day) | High end (4 mg/kg/day) | If split, twice daily |
|---|---|---|---|
| 5 kg (11 lb) | 10 mg | 20 mg | 10 mg every 12 h |
| 10 kg (22 lb) | 20 mg | 40 mg | 20 mg every 12 h |
| 15 kg (33 lb) | 30 mg | 60 mg | 30 mg every 12 h |
| 20 kg (44 lb) | 40 mg | 80 mg | 40 mg every 12 h |
| 30 kg (66 lb) | 60 mg | 120 mg | 60 mg every 12 h |
| 40 kg (88 lb) | 80 mg | 160 mg | 80 mg every 12 h |
| 50 kg (110 lb) | 100 mg | 200 mg | 100 mg every 12 h |
Tablets come in 25 mg, 75 mg and 100 mg and are scored, so the dispensed dose gets rounded to what a tablet can actually deliver. That rounding is our job. Don't recalculate at home and change the tablet count yourself.
One thing that confuses owners: if you read a Rimadyl package insert, it may quote 4.4 mg/kg once daily or 2.2 mg/kg twice daily.2 That's the North American labelling. It sits at the top of the same range, and it's why your prescription might read a little lower than the box does.
Carprofen can be given with or without food.2 I'd give it with a meal anyway. It doesn't change how the drug works, but it makes stomach upset less likely. If you miss a dose, give it when you remember, or skip it if you're close to the next one. Never double up. The chewables taste like a treat, so keep the bottle somewhere your dog can't reach.
Treatment length depends on the response, but any dog still on carprofen at two weeks should be looked at again, not just refilled.1
Most dogs take carprofen without trouble, and the numbers back that up. Kidney and liver reactions are classed as rare, meaning 1 to 10 dogs per 10,000 treated.1
The common problems are digestive and behavioural: vomiting, loose stool or diarrhea, blood in the stool, appetite loss, lethargy. These usually appear in the first week of treatment and settle once the drug stops.1 Tell us. Don't push through them.
The serious ones are the reason for the callout at the top. Ulceration with bleeding, which shows as black tarry stool or blood in vomit. Liver injury, which shows as yellow gums or eyes with lethargy and appetite loss. Kidney injury. Carprofen also affects platelet function, so unexplained bruising is worth a call.
The liver reaction is idiosyncratic, which means it isn't dose-related and you can't predict it.1 In the original case series of 21 affected dogs, 13 were Labrador Retrievers, and roughly a third of reported cases since have been Labs.4,5 That sounds alarming until you consider how many Labradors are on this drug for joint disease in the first place. A true breed predisposition has never been shown.4 I keep it in mind with a Lab, and I still prescribe carprofen to Labs.
The label is direct about this, and it matches how I practise. Carprofen shouldn't be used in dogs with heart, liver or kidney disease, in dogs at risk of gastrointestinal ulceration or bleeding, or in dogs with a clotting disorder.1 Older dogs carry additional risk, and dehydrated or hypotensive dogs shouldn't get it at all.1 In practice it's more often a risk and benefit call than a flat no, and it's one I'd want to make with you in the room.
So if your dog has been staged for kidney disease or has elevated liver enzymes, say so before the first dose. It changes the plan, and there are good alternatives now.
Blood and urine testing is recommended before starting any NSAID, and periodically while a dog stays on one.7
It finds the dog who shouldn't be on carprofen at all, and it gives us something to compare against later. If your dog's ALT climbs three months in, a baseline is what tells us whether that's new. For a dog on long-term carprofen I'd want bloodwork every six to twelve months, which usually folds into the senior check-up they're due for anyway.
You should also receive a Client Information Sheet with every NSAID prescription. That's a requirement, not a courtesy.7 Ask if you didn't get one.
One NSAID at a time, and no NSAID within 24 hours of a corticosteroid.1 Combining carprofen with another NSAID or with prednisone sharply raises the risk of ulceration and bleeding. That includes aspirin, and it includes whatever is left over in the cupboard from a previous prescription.
When we switch a dog between NSAIDs, or off prednisone onto carprofen, there needs to be a washout period in between.7 I generally use about a week. If a dog is too sore to wait, we shorten it deliberately and watch closely.
| Option | How it's given | Where it fits | Watch-outs |
|---|---|---|---|
| Another NSAID (meloxicam, firocoxib, robenacoxib) | Daily, oral | Dogs who tolerate the class but didn't respond to carprofen | Same class risks, and a washout in between6,7 |
| Grapiprant | Daily, oral | Arthritis pain where you want to avoid COX inhibition | Blocks the EP4 receptor instead, so no liver, kidney or platelet effects were seen in safety work. Mild digestive signs still occur8 |
| Bedinvetmab (anti-NGF antibody) | Monthly injection, in clinic | Arthritic dogs where a daily NSAID is a poor idea, or where pilling is a battle | Over 18 million doses given to mid-2024, adverse events reported at 9.48 per 10,000 doses, most often lack of effect, increased drinking, wobbliness and lethargy9 |
| Add-on pain drugs (gabapentin, tramadol, methocarbamol) | Oral, once to three times daily | Layered onto an NSAID for chronic or nerve pain | Sedation is the usual limit. Better as part of a plan than alone |
| Weight, conditioning and physical treatments | Ongoing | Every arthritic dog | Slow, and the change that does the most over years |
For the arthritic dog who also has kidney or liver disease, grapiprant and bedinvetmab are the two I'd weigh first. Both exist because of that exact problem.8,9 More broadly, I'd rather layer several modest things, weight off, diet sorted, a low dose that works, something extra on bad days, than push one drug to its limit.
If your dog is on carprofen and doing well, check when the last bloodwork was. More than a year, book it. If something seems off, appetite, energy, stool colour, stop the drug and call. Don't wait for the next appointment.
If you're deciding whether to start, bring us what you've noticed at home. When your dog is stiffest, which stairs they avoid, whether they still get up to greet you. That tells me more than the exam room does, and it gives us something to measure against in six weeks. You can book online or call (519) 896-0532.
Most owners notice a difference within a day or two, and for a fresh injury or after surgery it can be the same day. Arthritis is slower. Give it a full week before you judge whether it is helping, which is also when we would look at reducing the dose.
Yes, many dogs stay on it for years. The condition for long-term use is monitoring. We want bloodwork before starting and then every six to twelve months, and we want to know about any change in appetite, energy or stool colour. A dog still on carprofen after two weeks should be reassessed rather than just refilled.
Not with another anti-inflammatory, and not within 24 hours of a steroid like prednisone. That combination sharply raises the risk of stomach ulcers and bleeding, and it includes aspirin. Carprofen also needs care alongside diuretics, ACE inhibitors and cyclosporine. Tell us everything your dog takes, including supplements.
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