There seems to be quite a range of meloxicam dosages published for rabbits, ranging from 0.2mg/kg to 1.5mg/kg!
One reason is due to differences in study design and objectives. Some studies looked at pharmacokinetics of meloxicam, while others looked at efficacy of meloxicam by measuring various indicators of pain post-surgery and response to meloxicam. Sometimes meloxicam is administered alone, sometimes in combination with other analgesics including opioids and local anaesthetics. Pain indicators differ between studies; some studies looked at things like appetite, faecal output, weight and activity levels, while others looked at the grimace scale.
Dosages in older textbooks are often extrapolations from dogs/cats before the rabbit studies were even conducted.
Pharmacokinetic studies show that healthy young rabbits require 1mg/kg to achieve plasma levels that are considered effective in providing analgesia in dogs, and there was no evidence of organ damage. But does that mean that that plasma level is required for rabbits for analgesic efficacy? Or that it’s safe in unhealthy or older rabbits or those undergoing surgery or larger populations and other breeds?
Efficacy studies are tricky to compare because of differences in study design, but we know that 0.5mg/kg provides better analgesia than 0.2mg/kg! We also know that multimodal analgesia is more effective than meloxicam alone.
The decision on what dose to use, in combination or alone, (or whether to use meloxicam at all) should be made on a case-by-case basis to reduce the risk of adverse effects, while ensuring your rabbit patient’s pain is well managed.
