BY: SAMANTHA BARTLETT, DVM
Until recently, Tramadol was a go to adjunct medication for osteoarthritis and orthopedic pain in dogs. Many osteoarthritis patients have been on a combination of NSAIDs and tramadol for years to help control their chronic pain. However, recent studies have shown that tramadol may not have the effectiveness that we originally assumed.
In 2011, research out of Kansas State University showed that the active metabolites of Tramadol were only found at peak plasma concentrations for 1-3 hours. Additionally, the KSU research found that the drug’s ability to reach peak plasma concentrations diminished with repeated dosing, suggesting that Tramadol is not suitable for chronic use in dogs. This research was published in the AJVR and was entitled, “Pharmacokinetics and antinociceptive effects of oral tramadol hydrochloride administration in Greyhounds”.
In February 2018, JAVMA published research by a team at the University of Georgia with funding from Morris Animal Foundation entitled, “Lack of effectiveness of tramadol hydrochloride for the treatment of pain and joint dysfunction in dogs with chronic osteoarthritis”. This research found that dogs taking tramadol showed no improvement in pain scores compared to a placebo. Dogs in the study all had chronic osteoarthritis of the elbow or stifle. In a randomized, double-blinded crossover study, the dogs were given either a placebo, Rimadyl or tramadol for 10 days. The dogs were assessed based on owner perception of pain and assessment of vertical ground reaction scores were assigned at the beginning and end of each treatment period. No significant changes were noted in vertical ground reaction scores at the beginning and end of treatment with tramadol or a placebo. However, significant increases were noted at the end of the Rimadyl treatments. This has led the authors of the study to conclude that tramadol is not an effective drug for the chronic management of osteoarthritis in dogs.
Both of these studies, among others, mentioned the phenomenon of caregiver bias. Owners reported perceived reduction in pain with tramadol, but force plate analysis showed no improvement over a placebo when the pet was placed on tramadol.
What hasn’t been shown by this research is the potential effects of using tramadol in combination with other pain medications. Further study may be warranted to rule out this possibility. However, at the current time, it would seem that the only benefits of giving tramadol for pain are very short term.
Perhaps even more importantly, knowledge of tramadol’s lack of efficacy in dogs for long term pain management, may help veterinarians in dealing with potential drug-seeking behavior from owners. The DEA has classified tramadol as a Schedule IV drug, which means the potential for abuse exists although it is a lower potential than most other opiates. However, research has shown that opiate users do seek and become dependent on tramadol. The fact that tramadol is now a DEA scheduled drug makes it less attractive to keep and prescribe in clinic for the purposes of tracking and inventory. With all of the other responsibilities thrown on veterinarians’ plates, this may be one less headache in the long run.
