Onisor tablets are palatable (flavoured with yeast and artificial beef) and are taken voluntarily by most dogs. Robenacoxib is a potent and selective inhibitor of the cyclooxygenase 2 enzyme (COX-2). The cyclooxygenase enzyme (COX) is present in two forms. COX-1 is the constitutive form of the enzyme and has protective functions, e.g. in the gastrointestinal tract and kidneys. COX-2 is the inducible form of the enzyme and is responsible for the production of mediators including prostaglandin E2 (PGE2) which induce pain, inflammation or fever.
In an in vitro whole blood assay in dogs, robenacoxib was approximately 140-fold selective for COX-2 as compared to COX-1. Robenacoxib produced marked inhibition of COX-2 activity and had no effect on COX-1 activity in dogs at oral doses ranging from 0.5 to 4 mg/kg. Robenacoxib tablets are therefore COX-1 sparing at recommended doses in dogs. Robenacoxib had analgesic and anti-inflammatory actions in an inflammation model in dogs with single oral doses ranging from 0.5 to 8 mg/kg, with a rapid onset of action (0.5h). In clinical trials robenacoxib tablets reduced the lameness and inflammation of dogs with chronic osteoarthritis.
After oral administration of robenacoxib flavoured tablets at 1 mg/kg without food, peak blood concentrations are attained rapidly with a Tmax of 0.5 hour. Co-administration of robenacoxib non-flavoured tablets with food produced no delay in Tmax but slightly lower values for peak blood concentrations.
Robenacoxib is highly bound to plasma proteins (>99%) and is extensively metabolised by the liver in dogs. Robenacoxib is cleared rapidly from the blood: after oral administration of the tablets, the terminal half-life in blood was 1.2 hour. Robenacoxib persists longer and at higher concentrations at sites of inflammation than in blood. Robenacoxib is excreted predominately via the biliary route (~65%) and the remainder via the kidneys. Repeated oral administration of robenacoxib to dogs at dosages of 2 -10 mg/kg for 6 months produced no change in blood profile, with neither accumulation of robenacoxib nor enzyme induction.
For oral use. Do not administer with food since clinical trials demonstrated better efficacy of robenacoxib when administered without food or at least 30 minutes before or after a meal. The tablets should not be divided or broken.
The recommended dose of robenacoxib is 1 mg/kg body weight with a range of 1-2 mg/kg. Administer once daily at the same time every day according to the table below. A clinical response is normally seen within a week. Treatment should be discontinued after 10 days if no clinical improvement is apparent.
For long term treatment, once clinical response has been observed, the dose of Onsior can be adjusted to the lowest effective individual dose reflecting that the degree of pain and inflammation associated with chronic osteoarthritis may vary over time. Regular monitoring should be undertaken by the veterinarian.
Do not use in dogs suffering from gastrointestinal ulceration or with hepatic disease. Do not use concomitantly with corticosteroids or other non-steroidal anti-inflammatory drugs (NSAIDs). Do not use in case of hypersensitivity to the active substance or to any of the excipients. In clinical studies, inadequate response to treatment was seen in 10-15% of the dogs. Because the safety of robenacoxob has not been established during pregnancy and lactation or in dogs used for breeding, Onsior is not recommended for use in pregnant or lactating dogs.
The safety of the veterinary medicinal product has not been established in dogs weighing less than 2.5 kg or under 3 months of age.
For long term therapy, liver enzymes should be monitored at the start of therapy, e.g. after 2, 4 and 8 weeks. Thereafter it is recommended to continue regular monitoring , e.g. every 3-6 months. Therapy should be discontinued if liver enzyme activities increase markedly or the dog shows clinical signs such as anorexia, apathy or vomiting in combination with elevated liver enzymes. In dogs treated up to 2 weeks no increases in liver enzyme activities were observed. However, with long term treatment, increases in liver enzyme activities were common. In most cases there were no clinical signs and the liver enzyme activities either stablilised or decreased with continued treatment. Increases in liver enzyme activities associated with clinical signs of anorexia, apathy or vomiting were uncommon.
Use in dogs with impaired cardiac, or renal function or dogs that are dehydrated, hypovolaemic or hypotensive may involve additional risks. If use cannot be avoided, these dogs require careful monitoring. Gastrointestinal adverse events were reported very commonly, but most cases were mild and recovered without treatment. Vomiting and soft faeces were very common, decreased appetite and diarrhoea were common, and blood in the faeces was uncommon.
Use this product under strict veterinary monitoring in dogs with a risk of gastrointestinal ulcers, or if the dog previously displayed intolerance to other NSAIDs.
Onsior must not be administered in conjunction with other NSAIDs. Pre-treatment with other anti-inflammatory medicines may result in additional or increased adverse effects and accordingly a treatment-free period with such substances should be observed for at least 24 hours before the commencement of treatment with Onsior. The treatment-free period, however, should take into account the pharmacokinetic properties of the products used previously.
Concomitant treatment with medicines displaying action on renal flow, e.g. diuretics or angiotensin converting enzyme (ACE) inhibitors, should be subject to clinical monitoring. Concurrent administration of potentially nephrotoxic medicines should be avoided as there might be an increased risk of renal toxicity.
Concurrent use of other active substances that have a high degree of protein binding may compete with robenacoxib for binding and thus lead to toxic effects. Do not store above 25°C. Wash hands after use of the veterinary medicinal product.
In case of accidental ingestion, seek medical advice immediately and show the package leaflet or the label to the physician. In small children, accidental ingestion increases the risk for NSAID adverse effects.
For pregnant women, particularly near term pregnant women, prolonged dermal exposure increases the risk of premature closure of the ductus arteriosus in the foetus. Any unused veterinary medicinal product or waste materials derived from such veterinary medicinal products should be disposed of in accordance with local requirements.
Cardboard box containing 1,2,4 or 10 Alu/Alu blisters. Each blister contains 7 tablets.
In healthy young dogs aged 5-6 months, oral robenacoxib administered at high overdosed (4, 6, or 10 mg/kg/day for 6 months) did not produce any signs of toxicity, including no evidence of any gastrointestinal, kidney or liver toxicity and no effect on bleeding time. Robenacoxib also had no detrimental effects on cartilages or joints.
As with any NSAID, overdose may cause gastrointestinal, kidney, or liver toxicity in sensitive or compromised dogs. There is no specific antidote. Symptomatic, supportive therapy is recommended consisting of administration of gastrointestinal protective agents and infusion of isotonic saline.