My poor old boy - any advice please?

[loopsaloo]

Dcat has just turned 15, we have had him 3 years from a rescue. He's always been just fine, if a little chunky.
When the hot weather started, he went off his food which I thought was fairly normal. It's 2-3 weeks later, he's lost weight - he had full blood tests done with the vet which were all really normal.
I just can't get him to pick up his appetite.
I'm really worried and am trying all sorts of different foods to tempt him. He is still drinking water, interested in what we have to eat, eats treats and small amounts of cat food and fish.
The vet prescribed Loxicam for him as she said we have to assume he's having pain somewhere, it'll be day 5 of that today.
Can anyone offer any advice? I'm so worried

One of my older cats was similar as she neared the end of her days, however in her case, the vet quickly established kidney cancer and she died a few days later. I hope this doesn't sound too doom laden and hopefully he will pick up but as with humans, it can be a sign - but maybe keep going with small portions of favourite foods and hope for the best

I think you need to go back to the vet.
My ten year old cat has reduced appetite with subsequent weight loss due to stage 2 kidney disease so the vet has put her on mirtazipine 2-3 times a week which stimulates her appetite. It has worked & she's eating more.

if my cat goes off her food I keep giving her lick i licks- something better than nothing

As all bloods are normal it's not kidneys or thyroid which are often the culprits for elderly cat weight loss. Did the vet check his teeth?
Did they also do his blood pressure at all? as elderly cats can get high blood pressure which can cause all sorts of problems.

I think it's probably wise for a return vet visit to get to the bottom of it as you know him best and you sound like you know there's something not quite right with him.

We gave outs oralade or similar name, basically lucozade for cats