Monkey is now on his 3rd full day of medications (enalapril and lasix) and what a difference 3 days makes!! All week, I sat up all night like a new mother, watching him struggle to breathe and worrying intensely. I cried more than I slept this week. And today? He's 100% back to his old self. He's still a little rattly in his lungs (I suspect that there's still an allergy component working against him too) but he's breathing at a regular tempo and not laboring at all to breathe. So for any google searchers (like me) that couldn't find any answers:
Q: How long for lasix to take effect in cats?
A: In my experience, about 2 days. About 48 hours from his first dose, he was breathing normally again and the diuretic was fully at work (which means extra upkeep on the litter box - he's drinking tons of water and peeing all the time, which is good). The fluid seemed to drain away from his lungs and he was breathing and sleeping normal again. After the 2nd night of easy breathing, and presumably good rest, he was like a kitten again. Full of energy and wanting to play and talk a lot. It's a pretty drastic transition, and one that I am extremely grateful for.
The added bonus is that our other cat, Ruckus, has been a real sourpuss since Monkey got sick. He's always been the "little brother" and subservient cat and when Monkey was sick I think it spooked him. After a trip to the vet where Monkey had a urine sample taken (and some got on his legs) I think he smelled like high-volume I want to kill you pheromones and Ruckus was really creeped out by it. Ruckus is the kind of cat that is so gentle and easy going that it takes a LOT to upset him (he'll tolerate baby clothes and toenail trimming and small children pulling his tail with nothing more than eye-rolling) but he'd started hissing and growling at Monkey right away which tapered off a bit, except the now-and-then reassurtion of I don't like you which was uncharacteristic, but more tolerated. Now that Monkey is feeling better, he's stopped tolerating all this name-calling and has started issuing beat-downs. Which makes me feel better because #1 - he's physically able to kick some ass and #2 - Ruckus is being put "back in his place" as the little brother, so the house is less tense now. There's no one jockeying for position and all is as it should be. For the record: I hate it when the cats fight. I always stop them, even though I know it's "good" for them (they're not tearing each other apart, mostly just shoving and punching each other in the face while having a staring contest), because it determines dominance in the house, blah blah blah. So it's not my favorite part of Monkey's healing that they're fighting again, but at least I know that some measure of order is returning. And THAT is priceless.