[Epona]

I'm not a vet, but most good vets will happily speak to you on the phone if you've got any concerns. Just give him/her a ring and describe the problems you've told us about here and I'm sure they'll suggest whether that's normal. It's probably a normal side-effect since many medications can mess with your digestion, but it could be an allergic reaction so best check it out. And obvioulsy if the symptoms get any worse or become continual, take him to the surgery straight away.

Hope he gets better soon.