First of all there's no problem in working out while on the medication , aerobics
is the way to go for fat loss and speeding up your metabolism
, stay away from heavy weights , i'd reccomend you to use light weights if at all you are using them.
Well about the part about goin off the medication , yes you can but it totally depends on you , you have to keep your diet in check and reduce sodium intake.
Thank you and take care