Patients should have a pre-administration clinical and routine laboratory evaluation. Two weeks post-initiation of treatment, liver enzymes or bilirubin should be checked. For long-term therapy, clinical and laboratory evaluation should be at least yearly, perhaps every 6 months.

No NSAIDs are registered for cats in the US, but both meloxicam and ketoprofen are registered for cats in Canada and Europe, and appear to be relatively safe in cats.

Dose that has been used by some veterinarians (off-label): Meloxicam, available as injectable and flavored syrup (volume is small so cats seem to tolerate taste), at 0.1 mg/kg q24h for 2-3 days initially, then 0.025-0.05 mg/kg 2 -3x per week for longer term use.

Ketoprofen, available in injectable and oral forms, at 2 mg/kg once; then 1 mg/kg daily.

Carprofen is approved in Europe for cats, but for short-term use only.

Tramadol has mild analgesic properties and multiple modes of action, with some opiate effects but it is not a controlled substance. Pharmacologically, tramadol has an α2-agonist effect, and antiserotonin and opiate receptor effects, but the mechanism that contributes to analgesia is unknown. The drug is inexpensive, and available as the generic product. There are no studies reported to document its safety and efficacy , although there is a pharmacokinetic study reported to define its absorption and disposition in dogs. It tends not to cause vomiting as with opioids. It has been administered with NSAIDs without any known problems.

Trials have not been done in dogs to establish doses. Based on pharmacokinetic studies, a dose in dogs of 5mg/kg orally every 6 hrs will produce plasma concentrations considered to be in the therapeutic range. Doses have not been established for cats.

For acute pain, such as in perioperative use, veterinarians have administered injectable NSAIDs with good results. Drugs used in these instances include ketoprofen, flunixin meglumine, carprofen, tolfenamic acid (Tolfedine®, available outside the U.S.), and ketorolac tromethamine (Toradol®). These drugs have been used for 1-2 days to decrease fever and pain from surgery or trauma. Pre-operative injections of carprofen to dogs were shown to be beneficial to decrease post-operative pain in dogs after ovariohysterectomy.

Oral NSAIDs also may be used for acute treatment of myositis, arthritis, and post-operative pain, or they may be administered chronically for osteoarthritis. FDA-registered drugs that are administered in the US to dogs include: carprofen, etodolac, deracoxib, meloxicam, and tepoxalin. Human drugs that are sometimes used off-label include aspirin, piroxicam, ketoprofen, and naproxen. For cats, most experience has been with meloxicam, ketoprofen, and "children's" aspirin. Outside the US, carprofen, ketoprofen, tolfenamic acid, and meloxicam are registered for treatment of osteoarthritis in dogs. In North America and Europe, all these drugs have been administered with dietary supplements such as glucosamine and chondroitin sulfate.

There are studies available for each drug showing dosage regimens, and efficacy in comparison to placebo, for the treatment of pain associated with osteoarthritis. When drugs are compared to one another, it is difficult to demonstrate differences between these drugs for reducing pain in animals. Some studies have attempted to show which of the above drugs is safest. When carprofen, meloxicam, and ketoprofen were compared in dogs by endoscopic evaluation, there were no significant adverse effects produced, or differences among the drugs with respect to gastroduodenal lesions. Aspirin, at least after acute administration, has been shown to induce mucosal injury, gastritis, and hemorrhage in dogs. After administration of carprofen, aspirin, and etodolac at recommended doses to dogs for 28 days, there was significantly less gastroduodenal lesions from carprofen and etodolac as compared to aspirin. The effects of carprofen and etodolac were no different from those of placebo.

There are several choices for treating dogs with osteoarthritis with NSAIDs. Like people, there may be greater differences among individuals in their response than there are differences among the drugs. Some veterinarians have selected aspirin as an initial drug, because it is inexpensive and familiar to most pet owners. But, other veterinarians prefer to select an FDA-approved drug such as the etodolac, carprofen, deracoxib, meloxicam and tepoxalin for treatment in dogs. Some veterinarians still rely on human drugs used in an extra-label manner to treat patients refractory to approved animal drugs. These drugs include piroxicam (Feldene®), naproxen (Aleve®), and ketoprofen (Orudis®). These have not undergone safety and efficacy trials in the US. Outside the US, in Canada and Europe, other popular NSAIDs used in small animals include ketoprofen and tolfenamic acid. They have a relatively good safety profile and clinical results have been documented.

For treatment of pain with NSAIDs in cats, none are registered in the US, and only ketoprofen and meloxicam are approved for use in other countries and shown to be safe. In the US, ketoprofen is available as a 12.5mg tablet for people, available over-the-counter (Orudis-KT®). Aspirin is sometimes used in cats, with a "children's aspirin" administered (81 mg tablet) at a dose of 20 mg/kg every 48 hours.