Vet finally got round to telling me about this tonight, but there is a downside to it - it is 3 times more expensive than the dog one, but 4 times more concentrated (or the other way round!!). Sadly, they have to give the cat one first, so that means more animals are going to miss out due to cost - she was telling me about a dog drug that the same has happened to, it cost £15 for one days worth for a 40kg dog, compared to £2 for the old med.