I didn't sign up for it, because it only allowed for six drugs to be listed. (Lupies of the world, you have full permission to laugh for the next 15 minutes or more.)
I'm currently on 12 medications. (Sad, but true. Sometimes I wonder if I could get away with having my pills instead of meals rather than with them.) Some of them are to counteract the side effects of others. Some are for things like asthma and allergies, not just lupus. I just have to count on my GP to know what she's prescribed, what the specialist has prescribed, and to keep checking that they are all OK together - something I know she's careful to do.
It is possible for drugs to react badly with each other. It's a serious matter, and it's important that every time your medicine's changed you check that everything will still work OK together. If you're not sure about yours, you could ask the internet, but it might be better to check with your doctor!