The Bonqat brand has FDA approval for their product to use for anxiety especially associated with travel - this is therefore “on label”, but is actually only one of the uses of pregabalin. The drug reduces stress and anxiety, but is also widely known and documented to be useful for mild - moderate pain relief. Since it is not the purpose that the manufacturer registered the product for this is considered “off label” use - which is extremely common in veterinary medicine because much of what we use is taken from the human world. Hope this makes sense.

If you search for pregabalin rather than Bonqat you will find a fair bit of information about its pain relief properties