Amabaglen, I've had a hunt round the internet but can't find the exact lorbex ingredient list anywhere.
Treat it as a 'possible' poisoning - you never know, they may have chewed the container, not liked the taste and most of it soaked into the carpet?
Call the vet immediately (even if it is a bank holiday weekend, get them out/ ask for advice just to be on the safe side and take the cost on the chin). Your dog may start to vomit, go shaky (or show changes from their usual behaviour) or drink water excessively, but please do call the vet now for help - that is what they are there to do.
All the very best