Allopurinol
Uric Acid Reducer
View Brand Names (1)Dose and dosage
For gout:
a) Poultry: 25mg/kg body weight
b) In budgies and cockatiels: Crush one 100 mg tablet into 10 mL of
water. Add 20 drops of this solution to one ounce of drinking water.
c) For parakeets: Crush one 100 mg tablet into 10 mL of water. Add 20
drops of this solution to one ounce of drinking water or give 1 drop 4
times daily.
For urate uroliths:
a) For dissolution: 15 mg/kg PO q12h; only in conjunction with low purine foods.
For prevention: 10–20 mg/kg/day; because prolonged high doses of allopurinol may result in xanthine uroliths, it may be preferable to minimize recurrence with dietary therapy, with the option of treating infrequent episodes of urate urolith formation with dissolution protocols. (Osborne et al. 2003)
b) 7–10 mg/kg PO three times daily for both dissolution and prevention. Goal is to reduce urine urate:creatinine ratio by 50%. (Senior 1989)
For Leishmaniasis:
a) First line treatment: Meglumine antimoniate (N-methylglucamine antimoniate) 75 - 100 mg/kg once daily for 4-8 weeks plus allopurinol 10 mg/kg PO twice daily for 6-12 months.
Second line treatment: Miltofosine 2 mg/kg PO once daily for 4 weeks plus allopurinol 10 mg/kg PO twice daily for 6-12 months OR allopurinol alone at 10 mg/kg PO twice daily for 6-12 months. (Solano-Gallego et al. 2009)
b) Meglumine antimoniate (100 mg/kg/day SQ) until resolution, with allopurinol at 20 mg/kg PO q12h for 9 months.
An alternate protocol using allopurinol alone: allopurinol 10 mg/kg PO q8h or 10–20 mg/kg PO q12h for 1–4 months. (Brosey 2005)
c) If possible use with meglumine antimoniate, if not, use allopurinol alone at 10 mg/kg PO twice daily. If animal has renal insufficiency, use at 5 mg/kg PO twice daily. (Font 1999)
d) 15 mg/kg PO twice daily for months (Lappin 2000)
a) For elevated uric acid levels in renal disease in lizards: 20 mg/kg PO once daily (de la Navarre 2003)
b) For gout: 20 mg/kg PO once daily. Suggested dosage based upon human data as dose is not established for reptiles. (Johnson-Delaney
2005)
c) For hyperuricemia in green iguanas: 25 mg/kg PO daily. (Hernandez- Divers et al. 2008)
- High Blood Uric Acid Level
- Gout
prevention and treatment of high blood uric acid level and gout, prevents deposition of urate crystal in kidney, serous membranes of liver, heart, air sac and joints of poultry.
The principle veterinary uses for allopurinol are for the prophylactic treatment of recurrent uric acid uroliths and hyperuricosuric calcium oxalate uroliths in dogs, particularly Dalmatians. It has also been used in an attempt to treat gout in pet birds and reptiles.
Allopurinol has been recommended as an alternative treatment for canine
Leishmaniasis. Although it appears to have clinical efficacy, it must be used for many months of treatment and does not apparently clear the parasite in most dogs at usual dosages. Allopurinol may also be useful for American Trypanosomiasis.
N/A
Allopurinol is contraindicated in patients who are hypersensitive to it or have previously developed a severe reaction to it. It should be used cautiously and with intensified monitoring in patients with impaired hepatic or renal function.
When used in patients with renal insufficiency, dosage reductions and increased monitoring are usually warranted.
Allopurinol does not appear to be effective in dissolving urate uroliths in dogs with portovascular anomalies.
Allopurinol and its metabolite, oxypurinol, inhibit the enzyme xanthine oxidase. Xanthine oxidase is responsible for the conversion of oxypurines (e.g., hypoxanthine, xanthine) to uric acid. Hepatic microsomal enzymes may also be inhibited by allopurinol. It does not increase the renal excretion of uric acid nor does it possess any anti-inflammatory or analgesic activity.
Allopurinol is metabolized by Leishmania into an inactive form of inosine that is incorporated into the organism’s RNA leading to faulty protein and RNA synthesis.
Allopurinol, by inhibiting xanthine oxidase, can inhibit the formation of superoxide anion radicals, thereby providing protection against hemorrhagic shock and myocardial ischemia in laboratory conditions. The clinical use of the drug for these indications requires further study.
The following drug interactions have either been reported or are theoretical in humans or animals receiving allopurinol and may be of significance in
veterinary patients:
ANTICOAGULANT: Allopurinol prolongs the half life of the anticoagulant, dicoumarol.
DIURETICS: Concomitant use of Allopurinol and thiazide diuretics may contribute to the enhancement of Allopurinol toxicity.
CYTOTOXIC AGENT: Enhanced bone marrow suppression by cyclophosphamide and other cytotoxic agent has been reported among patients with neoplastic disease.
AMINOPHYLLINE or THEOPHYLLINE: Large doses of allopurinol may decrease metabolism thereby increasing their serum levels
AMOXICILLIN or AMPICILLIN: In humans, concomitant use with allopurinol has been implicated in increased occurrences of skin rashes; the veterinary significance of this interaction is unknown
AZATHIOPRINE or MERCAPTOPURINE: Allopurinol may inhibit metabolism and increase toxicity; if concurrent use is necessary, dosages of the antineoplastic/immunosuppressive agent should be reduced initially to 25–33% of their usual dose and then adjusted, dependent upon patient’s response
CHLORPROPAMIDE: Allopurinol may increase risks for hypoglycemia and hepato-renal reactions
CYCLOPHOSPHAMIDE: Increased bone marrow depression may occur in patients receiving both allopurinol and cyclophosphamide
CYCLOSPORINE: Allopurinol may increase cyclosporine levels
DIURETICS (Furosemide, Thiazides, Diazoxide, and Alcohol): Can increase uric acid levels
ORAL ANTICOAGULANTS (e.g., Warfarin): Allopurinol may reduce the metabolism of warfarin thereby increasing effect
TRIMETHOPRIM/SULFAMETHOXAZOLE: In a few human patients, thrombocytopenia has occurred when used with allopurinol
URICOSURIC AGENTS (e.g., Probenecid, Sulfinpyrazone): May increase the renal excretion of oxypurinol and thereby reduce xanthine oxidase inhibition; in treating hyperuricemia the additive effects on blood uric acid may, in fact, be beneficial to the patient
URINARY ACIDIFIERS (e.g., Methionine, Ammonium Chloride) May reduce the solubility of uric acid in the urine and induce urolithiasis
The most frequent adverse reaction to Allopurinol is skin rash such as, pruritic maculopapular skin eruptions, sometimes scaly or exfoliative.
Over dosage may cause diarrhea, abdominal pain and neurotoxicity.