Excessive Yowling and energy

My cat was at the vet in October. All was well. 

But in the last two weeks he has suffered from excessive yowling (of course at night).  Before he would always seem to respond to shaking the coin can but it isn't working anymore (though he hears it). I know that he is hungry and don't have him on a diet but... I feel like he is just taking advantage. 

He also used to sleep about 12 hour a day and now.. more like 6. 

I have a suspicion about medication...he takes asthma meds and sometimes a new dose can make him a bit more energetic. But I really feel concerned.  Plus I am sleep deprived.  I am considering today and tonight keeping him up late and not letting him sleep and also giving him his food late. 

Are there any symptoms that would make me think he needs to go to the vet again? 

Overall he seems happy and healthy. He played like a kitten his morning. Going piddle and poop regularly. He doesn't seem in pain...  He is 10 going on 11 in May. 

What meds is he on for asthma? He probably gets more energetic because he can breath better and doesn't struggle when running around. That's just speculation though.
My cat also has asthma and when she was getting steroid shots for it she was always hungry. Iv since been able to switch her to an inhaler to manage her asthma and she doesn't seem to get hungry like she used to.
There is a food that royal canin make. I think it's called satiety or something similar. It is designed to make your cat feel more full for longer periods of time. Maybe you could give that a shot.

inhaler..  flixotide... flovent.

It almost feels like when the meds are new they are more effective. I will try that food. 

I agree with you there on the meds working better when they are new. Sometimes i only use half the inhaler before replacing it as it seems to not work as well after the first half.
Maybe it would be better to talk to your vet before trying that food. If you are feeding him normal amounts and he isn't getting a steroid shot for the asthma there may be another reason he is so hungry. Do you de worm him regularly?

When he was at the vet in October did he have any blood work done? The symptoms you describe could mean he has an over active thyroid. Typically the first signs of hyperthyroidism are constant hunger with weight loss, restlessness, and excessive meowing. Steroids can certainly cause these symptoms too (minus the weight loss) but it would certainly be worth running a T4 blood test if he hasn't had one.

Yes.. the blood panel came back fine. 

I am no seeing any other symptoms... (such as weight loss) 

Where would he get worms if he was an only indoor cat? I don't particularly want to go to the vet if I can avoid it. She never met and expensive test she didn't like.