Allopurinol for Dogs: Dosage and Side Effects

There are many scenarios in which drugs used in human medicine can be used in animals. This is the case of allopurinol for dogs, a compound that’s used in the treatment of leishmaniasis in canines, although in humans it’s an effective method to reduce the level of uric acid in the blood.

It’s estimated that 7% of the canine population in regions such as Spain suffers from leishmaniasis. In addition, it’s a disease that’s hardly ever completely cured, although the animal may live without obvious symptoms. If you want to know more about the treatment for this disease, here’s the basic information about allopurinol.

What’s allopurinol for dogs?

Allopurinol is an active ingredient that works as an enzyme inhibitor of the protein that metabolizes xanthine to convert it into uric acid. Since this compound doesn’t eliminate the leishmanial parasite, it’s used as an adjuvant treatment to antimonial salts and miltefosine, which are parasiticides.

This drug is administered orally and treatment initially lasts from 6 months to 1 year. However, the period can be extended depending on the state of health of the animal and even prescribed for life. Depending on the individual dog, the different drugs against leishmaniasis are combined individually.

Allopurinol for dogs with leishmaniasis

Leishmaniasis is a parasitic disease caused by a protozoan, Leishmania infantum. This parasite enters the animal’s body through the bite of phlebotomine sandflies (usually Phlebotomo perniciosus and Phlebotomo ariasi). Moreover, it’s a zoonotic disease that can only be avoided through prevention.

Once the dog is infested by the parasite, it lodges in the tissues of the animal’s organs, compromising its functions as it reproduces. Depending on the state of health of the dog, it may or may not advance rapidly, until it causes the systemic failure that results in death.

Symptoms will therefore depend on which organs are affected by the parasite.

Miltefosine and antimonials are leishmanicidal drugs, i.e. they eliminate the parasite from the body. Unfortunately, this pathogen replicates very quickly, so sometimes their uses as antiparasitics aren’t enough. This is where Allopurinol comes in with its leishmanistatic effect, as it slows the multiplication of the parasite.

Dosage of allopurinol for dogs

Allopurinol for dogs is marketed in 2 formats: 100 and 300 milligrams per tablet. The veterinarian will tell you the exact amount that your dog should take with respect to its body weight. It’s usually administered orally 2 times a day.

Remember that allopurinol, like any other drug, shouldn’t be administered without following the advice of a veterinarian. Also, you shouldn’t have to stop treatment without its approval even if the health of the dog seems to improve.

Side effects of allopurinol

Due to the action that allopurinol has on the metabolism of uric acid, it may cause certain side effects. Specifically, here are 2 of the most common side effects:

1. Xanthinuria: The chronic use of allopurinol can cause an excessive accumulation of xanthine in the blood. When this occurs, the compound is eventually eliminated through the urine.
2. Urolithiasis: The accumulated xanthine can bind to organic and inorganic matter in the urine, crystallizing and forming uroliths or stones.

When these side effects appear, the most obvious clinical signs are urinary. You can read about them below:

• Dysuria: pain when urinating.
• Hematuria: presence of blood in the urine.
• Urinary incontinence.
• Urinary obstruction: this occurs due to the accumulation of uroliths. This is a veterinary emergency.
• Abdominal pain: You’ll know that the dog is in pain because of its posture and muscle tension, mainly in the abdomen.

Alternatives to allopurinol for dogs

Due to these side effects, the efficacy of allopurinol for dogs has been questioned in the scientific community. On the other hand, it’s now known that the treatment of leishmaniasis should include a specific diet that strengthens the immune system, the state of the skin and controls the renal stability of the dog.

Nowadays it’s easy to find dog food manufactured specifically for the treatment of leishmaniasis. Its intake prevents the formation of xanthine crystals.

One of the alternative treatments to the use of allopurinol is Impromune, a food supplement based on nucleotides that strengthens the immune system of the animal. Its consumption helps to slow the progression of leishmaniasis without any adverse effects.