Not that I've seen, he's just not gone for at least 3 days, and normally has at least 1 shit a day. He's not drinking as much water either (maybe cos he's not licking all his fur off his legs now?). Tried him with a bit of milk, but that's done nowt.Is he straining to go but nothing coming out? If so, he may have got a blockage somewhere. One of my cats did this years ago and when the vet gave him an enema a whole fish head came out so he must have been raiding someone's bins.
You can give cats the human drug lactose. I know the maintenance dose for cats prone to constipation is 2 mls a day but he'd need something stronger than that so best to run it past the vet first.
Will see if this Laxapet shifts him.