Sometimes people (and rats) can have reactions to certain drugs- pain in the stomach, dizzyness, etc). I have had several ratties on meds in the past and present. One boy refused to take his meds; I couldn't force feed them into him, but eventually tricked him a few times - and then he had seizures (for a whole day)! I stopped all his meds, and he very gradually recovered over the weekend back to normal. Now, coincidence? or cause and effect? I think that it was the drugs. Now my other rats can take it (I think it was the doxycycline), but in him it caused a reaction. He knew it made him feel terrible and tried not to eat it but I sneaked it into him. He seemed OK on the Baytril on its own, but it wasn't doing the job. Several weeks later he succumbed to his illness, but I believe it was CHF and not lung issues that killed him. I wasn't able to medicate him long enough to eliminate respiratory problems as the cause of his rapid breathing.
So the moral of the story is, sometimes the rat knows something but just can't communicate it to us. If they're dead set against taking a certain drug, maybe there's a reason for it, and not just taste.
