I've taken Norethisterone a few times, but I haven't in a long time--it wouldn't be my first or second choice due to the side effects--mainly very painful cramping that just won't stop and a nauseous feeling. It's basically synthetic progesterone, so there are many factors for how it will affect you. If you do take it, I'd recommend trying it during a non-busy time so you can be aware of what happens. The side effects can vary widely.
Currently I would just use a sponge. Some clients go crazy at the though of blood and a clean sponge is so important, and others are very accepting of it. Either way, I have to be super careful to change the first few days.