If you took 10 mg in the morning do you think after 12 hours that taking 7.5 mg would be felt at all 12 hours later? Not looking for the same "intensity" in feeling, just wondering if it will be effective again.
It should be, depends on your tolerance which will of course go up over time.
I have to wait at least 6 hours to get full effects again, but as far as pain killing properties even 7.5mg six hours after a 10mg would be effective for at least taking the edge off the pain, if not getting rid of most of it.
Last year I was abusing oxy pretty badly, but I was also taking it for pain as well. Before I blew my tolerance through the roof I was using:
10mg at breakfast (5am)
5mg around lunch (1pm, sometimes sooner)
5mg around supper (5pm)
and 7.5-10mg an hour before bed as needed (didn't always need it).
That kept the pain off all day well enough that I could work on my bum knee. These are just examples btw and based on my "almost virgin" tolerance. Later on I had to double, then triple, these numbers as I started chasing the itch instead of just taking them for pain.
Waiting 12 hours should be fine for you, and you could probably get away with taking it sooner. Just watch that you don't take too much too often or you'll have bigger problems.
