Thank you for the additional information. In most cases, the accepted dose of prozac is around 0.5-1.0mg/kg when treating cats for inappropriate urination. An 18lb cat is 8.1kgs, and at the low end of the dosage range (0.5mg/kg) the kitty would get just over 4mgs (8.1kgs X 0.5mgs = 4.09mgs prozac). A 1mg/kg dose would be 8mgs of prozac (8.1kgs X 1.0mg = 8.1mgs prozac). So the 5mgs that your cat is receiving is actually correct and within the normal dosage range. That being said, your kitty is having side effects that are not desirable, and his dose will need to be adjusted. Jasmine's dose may also benefit from an adjustment as well, though from your description it sounds like she is not as affected. Some cats, like some people, are more sensitive to certain medications than others. It can take several weeks (2-4 is the typical from what I have read) for Prozac to clear the system completely after it is discontinued. However, the true half life of prozac is not really known in cats. In dogs and humans it is thought to be lengthy, and is dictated by the length of time the patient has been taking the medication. So the longer the treatment, the longer the half life. Most patients are weaned slowly off of a drug like prozac, though there is some differences of opinion as to the necessity of doing so. In humans, if prozac is suddenly discontinued, there are unpleasant side effects, like localized, zapping pains. There is no evidence that this occurs in either dogs or cats. Other experts feel that suddenly stopping prozac can cause an increase in the undesirable behavior that the medication is used to treat. BotXXXXX XXXXXne? Lots of fancy ways to say we don't know, but everyone has an opinion and theory (Cats always sort of do their own thing anyway, don't they?).
Studies have shown that some cats do become very sedate and less responsive after starting prozac. There is very little information on whether these symptoms decrease over time because once this happens, owners collaborate with their vets and the dose is usually lowered. It sounds like Aladdin is a sensitive kitty when it comes to Prozac, much more of a "cheap date" than his lady friend Jasmine. I think it would be a good idea to contact your vet Monday morning and find out if it is practical to lower the dose. I am not comfortable advising you to discontinue the prozac, because there is so much disagreement over whether this is healthy or not. My experience with prozac and cats was different, as these particular felines were on 3mgs/day and had none of the side effects that can typically occur.
As far as urine removers, I have always used Natures Miracle (has a money back guarantee) or a product called Urine off. When used in conjunction with a black light, I have not had the need for another product. Since the urine has gotten into hardwood flooring, you might find it very difficult to completely remove it all without pulling up the boards and the padding underneath. The saturation probably involves a larger area than you would expect, and you will have limited success until it is all gone. Black lights are great because you can see all of the urine, which of course makes it easier to clean.
You sound like you are very well versed about inappropriate elimination, but I am including a link on the subject just to be thorough. It gives basic information on typical causes, typical drugs used to manage the issue, and how to clean urine stains etc. It also gives some great tips (did you know that there should usually be one litter box per cat in the house?). Worst case scenario, you read up on some medications you may not have heard of.
I think I have addressed all of your questions. If I have not, or if you have further questions, please don't hesitate to let me know. Good luck with Aladdin and Jasmine :)