When I started using Percs he used 5mg orally. This gave him a nice feeling and lasted about 4 hours. After about a year I had to go to 10mg also oral to get the same feeling. Now the 10's are not cuting it. I have used the grapefruit, tums and empty stomach to potentiate the Percs. It looks now like Swim will have to abstain for a while to get the habit down. What Swim needs to know is about how long to abstain to get more out of the dose to which I have developed a tolerance.