My cat has a UTI and stones. How long before he passes the stones?

My cat has uti and he is not peering and not eating and drinking that much . He does have stones but I don't know how long it will be before he passes them? I hate to see him like that. I do have Ned's for him for the vet.Hope someone can help me. Thanks Cora.

Has he urinated since you posted yesterday?  If not, this is absolutely an emergency!  He may have blocked and you need to get him to an Emergency Vet right away.

I'm sorry, but I'm not familiar with Ned's.  Are you in Europe?  When did you take him to the Vet...Did you get antibiotics or pain meds (perhaps Ned's is something like that?)  What did the Vet advise you? 

If the stones are not to big to help dissolve them ask the vet to prescribe special food that helps with it.