Although osteoarthritis (OA), which can be very painful, is well documented in cats,1-7 chronic pain is commonly undertreated in this species.3 Various factors, including cats’ ability to hide pain and a lack of information regarding analgesic drug use, contribute to undertreatment.3
In this study, indicators of pain (eg, mobility, lameness) markedly improved when cats with documented OA were treated with oral transmucosal meloxicam. Addition of tramadol did not further improve these pain indicators, but when hypersensitivity (central sensitization) was simulated, the addition of tramadol increased analgesia levels. Tramadol’s effect on hypersensitivity could be due to serotonin-norepinephrine reuptake inhibition (SNRI) rather than the drug’s opioid effects.8 An increased incidence of typical opioid-mediated adverse effects (eg, anorexia, depression) occurred with the addition of tramadol. A repeat study using an SNRI with no opioid effects could be useful.
Of note is the often-profound variability between cats in behavior, degree of pain relief, and incidence of adverse effects. This high variability in responses among cats is not unusual,9 which adds to the difficulty of studying cats.
Use of stair exercise to stress joints likely improved the ability to detect lameness using pressure mats, and collection of mobility data when humans were not present with the cats increased the likelihood of recording true cat behavior. Although there was variability between cats and the sample size was small, the positive response to analgesic treatment of OA with meloxicam should inspire practitioners to treat this painful disease.