As far as I know, there's two regimen, one consists of fasting for some days and taking AE to "test" the medication and be sure that everything will go flawless.
The other regimen is fasting for only 8 hours and in 1 hour take painkillers, 45 minutes the AE and then SN. This one is the fastest one, as there's no AE test or anything, but as there's no AE test, it could go wrong. Yet most people, like me, choose it.