So my housemates cat Clarence is on an anti-seizure medication now....Ryuk has always been fine with this cat...generally they ignore each other with the exception of a few turf wars over the couch (which is adorable, one will curl up next to the other than "accidentally" kick the other one off the cough while "stretching"). We actually first noticed the micro seizures because Ryuk started getting very pushy keep Clarence off of things higher than a foot off the ground and laying him down when he got unstable.

Clarence is adjusting to his meds, which apparently (and we did check with the vet) means he's high as a kite for the next few weeks....part of this means he WILL NOT stop trying to bury his face into the soft fur on Ryuk's neck, grooming him, chewing on his ears and tail, licking his tongue (this ones sort of odd to see) rubbing against him, etc. Every chance he get he tries to interact with my dog. Ryuk has been a good sport about this....but since he's never had to deal with Clarence being Mr. Lacks-Concept-Of-Personal-Space Cat he doesn't know how to react. He's resorted to simply moving away from him.....which would be great....except for one small issue...

Drugged cat has no idea where his feet are at the moment....so when Ryuk steps away...Clarence falls over and 9 times out of 10 it has been on his face.....not surprisingly Clarence doesn't like this so when Ryuk moves he's gone into cling mode and will follow him to maintain contact (even going as far as to grab on) so he doesn't fall over. Ryuk's been good but I can tell he's getting a bit sick of Cuddle Cat.

This isn't "my" cat and I'm not allowed to lock him up (though I have been when his owner's not home...he fell into the toilet the other day and could not get out)....but I don't want to confine Ryuk to my room when I'm not in it (especially since he's not doing anything). When I see Clarence in cling mode I'll pick up him up and move him (which means he clings to me for a few minutes -_-). Ryuk has to live with two new kitties come the end of the month....is this going to sour my dog to cats or should I make him put up with it until then?

***Ryuk is not showing any aggression...just more of an exhausted sort of behavior...the same face most dogs get with a really annoying little puppy they just won't correct. However what he's putting up with....I would have eaten the cat by now....

just because the cat isn't doing anything "wrong" doesn't mean it's bad to confine him to a room or something. it would just be like confining a dog or cat that just had surgery or something and was recovering. it seems like it benefit the cat especially since he keeps falling on his face? how long did the vet say these side effects will continue?

How about giving Ryuk the option of staying in your room, instead of forcing him to stay in there.

See if you can convince the roommate that confining the cat temporarily/periodically is necessary for his own safety (toilet incidence), and also to give Ryuk a break.
Are they aware of how annoying he has become?