Allopurinol is a xantihne oxidase inhibitor. Allopurinol is registered only for use in humans, but veterinarians do prescribe it as an extra-label drug.
The drug is often used in veterinary medicine to treat and prevent the formation of kidney stones.
How Allopurinol Works
Xanthine oxidase is an enzyme that converts certain chemicals in the body into uric acid which is, in its turn, transformed into allantoin. Allantoin is eliminated through the kidneys. Some organisms cannot transform uric acid into allantoin. When this happens, uric acid accumulates in the body leading to the formation of crystals which end up in deposits on the kidneys or bladder. In dogs, this condition is mostly common in Dalmatians. Dogs with a defective blood flow to the liver are also at risk of developing this condition. Allopurinol is a prescription drug that can treat this condition.
Uses of Allopurinol in Dogs
Allopurinol is often prescribed by veterinarians for dogs that have recurrent urate bladder and kidney stones.
Allopurinol can also be:
- given as a preventative for bladder stones in dogs with a risk of developing them
- used to treat gout in dogs.
- used effectively to treat canine leishmaniasis
Allopurinol can be found under certain brand names such as: Zyloprim, Progout, Allohexal and Zyloric.
Administration of Allopurinol
In dogs with bladder and kidney stones, Allopurinol can be given every 8 hours or every 12 hours. The usual dose is of 10 mg per kilogram (5mg per pound) or 15 mg per kilogram, depending on the frequency of administration. However, your vet will indicate the right dose.
Never stop administration before the time prescribed by your veterinarian, even if the symptoms of bladder or kidney stones may disappear; your dog might develop resistance to the drug and won’t react to it when administered again.
If the dog is still showing symptoms after you have finished the prescribed treatment, check with your veterinarian before supplementing the dose.
The vet will perform x-rays to see if the kidney stones have been eliminated.
Side Effects of Allopurinol in Dogs with Bladder Stones
Allopurinol shouldn’t be administered to your pet unless prescribed by a veterinarian. While the drug is generally safe for dogs, it can cause side effects, especially if given together with certain other drugs.
- Gastrointestinal upset
- Diarrhea
- Nausea
- Liver problems and rashes may occur if the drugs are taken together with Ampicilin or Amoxicilin.
- Allopurinol can interact with other medication such as azathioprine, methionine, furosemide and ammonium chloride
Precautions with Allopurinol in Dogs
Only your veterinarian can decide if Allopurinol is right for your pet. However, there are some cases in which the drug should be avoided:
- Dogs with a defective kidney or liver function should not be given Allopurinol
- Pregnant and lactating dogs
Allopurinol should not be used in animals that are hypersensitive or allergic to the drug. The vet will decide on an alternative treatment in this case. A change in diet or surgery may be other options.