This is my opinion as I used to be a Reductil user:
In my experience, it didn't stop working, the side effects stopped being so bad, your appetite will be smaller. Its excellent that the side effects subsided after only one week and if you keep using it, it'll do its job. I've put another post about reductil in another 'Reductil' section for more info if you want. Try this! go off it and you'll be starving. As I've said on here before it will only work effectively if you're doing exercise combined with a low fat, low calorie diet. Reductil won't work if you're still able to over-eat (that is, eat bigger meals than your body needs). Especially fatty foods (you can't expect it to work if you're eating fish and chips etc).
I hope that information helps .. please know I wasn't suggesting you're overeating fatty foods etc, I'm just relaying how it worked for me.
Good luck x
PS After a few months, I went to 15mg and halved it (which was very messy) so I was having about 7mg each morning. This cut my costs