Abstract
A Pesticides Safety Directorate report concluded that anticoagulant rodenticides are markedly inhumane, but they are the most widely used method for killing problem rodents. Adding analgesics to anticoagulant formulations has been suggested as a possible method of improving the humaneness of these rodenticides. A review of the literature on analgesics has identified meloxicam as a potentially suitable analgesic for this application (Defra Project WM0317). It has a relatively long duration of action such that it is only required to be administered once daily, and has been found to be as effective at treating post-operative pain in rats as an opioid analgesic. The effective dose of meloxicam appears low enough to permit a bait formulation that would deliver an effective dose if half of a rat’s daily food intake consisted of bait. The majority of rats visit a bait station at least once a day after they initially take the bait, and previous studies suggest that they take over half their intake from this source. Therefore rats should be able to consume the analgesic at an effective rate. No side effects have been reported during clinical use of meloxicam in rats, and small mammals. Its metabolites are chemically inert, and there is no anticipated synergistic interaction between the analgesic and the anticoagulant. We propose to determine by means of a proof of concept laboratory study if the analgesic meloxicam is effective at reducing pain during anticoagulant poisoning in rats.
United Kingdom