I think there may have been some confusion over my Metacam post the other week, possibly do to my own initial ill-mannered rantings. I’ve disabled the previous post (I will make it public again once I’ve edited it) and think that this new post will clarify my thoughts. I want to make it clear that my issue with Metacam is not it’s use in general, but with the lack of information related to it’s use in laboratory animals, specifically rodents .
Of course it is better to use some sort of pain relief than not at all and it’s great that a simple, easy to use drug such as Metacam is readily available. My first issue is that there does not seem to be the appropriate tests or reassurances in place regarding the safe use of this drug in small rodents. My second issue is that researchers, students and technicians need to be made (more) aware of the differences between NSAIDs like Metacam and opiods, like buprenorphine.
Regarding the first point: The recently published book Small Animal Clinical Pharmacology(2nd.Ed. 2008) lists Metacam as a drug used for the management of soft tissue or musculoskeletal pain, or for peri-operative pain in dogs undergoing orthopedic or soft tissue surgery (p.301). It also lists that it has recently been approved for short term use in cats and in Europe, for use in horses. Rodents are not listed at all.
The Health Canada Drug Database lists Metacam Oral Suspension 1.5mg/ml as a veterinary product for dogs. It lists injectable Metacam formulations as being available for dogs, cats and cattle.
There are studies in primary literature regarding the safety and efficacy of Metacam in rabbits (Carpenter et al. 2009, Turner et al. 2006), in dairy cattle (Hirsch and Phillip 2009) and of course dogs (many…), but there have not been published studies of Metacam in mice (that I know of).
Regarding my second point: If I were an investigator, and Metacam was suggested as an analgesic for my mice, would someone be able to tell me how this drug is metabolized, how long it takes to metabolize and what are its known side effects? These characteristics are known at least in general terms because NSAIDs are a well characterized group of drugs and veterinarians are presumably aware of these characteristics. So yes, I am sure that for planned experiments, vets will recommend appropriate drugs and labs will follow these guidelines. But when animals need unexpected treatment (eg. post-surgery complications, opened sutures, deep fight wounds, etc), vets are typically not consulted and these decisions are made in-house. Is your average tech well-informed such that they are able to recommend the correct treatment? Will they be able to tell an investigator about potential side effects, modes-of-action and possible interactions with current experimental treatments?
I think it’s important to be aware of the science behind the techniques we use. Some procedures and conditions are probably managed fine with Metacam while other procedures are probably better managed with opiods or through a combination of drugs. But underlying the choice of which drugs to use should be knowledge of the drug and its effects on the species you are working with. This should be true whether you are a post-doc, a student or a tech and it is in that respect that I think that a lot of people are not completely aware of the limitations of Metacam.
James W. Carpenter, Christal G. Pollock, David E. Koch, Robert P. Hunter (2009) Single and Multiple-Dose Pharmacokinetics of Meloxicam After Oral Administration to the Rabbit (Oryctolagus cuniculus). Journal of Zoo and Wildlife Medicine: December 2009, Vol. 40, No. 4, pp. 601-606.
Patricia V. Turner, Cheng H. Chen, Michael W. Taylor (2006) Pharmacokinetics of Meloxicam in Rabbits After Single and Repeat Oral Dosing. Comparative Medicine, Volume 56, Number 1, February 2006 , pp. 63-67(5)
AC Hirsh and H Philipp (2009) Effects of meloxicam on reproduction parameters in dairy cattle. Journal of Veterinary Pharmacology and Therapeutics Volume 32, Issue 6, pages 566–570, December 2009