When a doctor preforms a blood test for amount of medication in your blood should this be done at a certain time frame? Something like taking it after last dose was taken. I had a blood test done for amount of meds. In my system and it was done an hour after I had taken my meds. Won't this show up for a larger amount. I am on oxycontin 40mg. Three times a day, oxycodone 10mg. 5 times a day and valium10mg. 4 times a day. I read that in the first hr. of taking oxycontin it releases the largest amount within an hour then releases 6mg. And hr there after. Don't know if this is true, but wouldn't this make my test come up that I am taking more then prescribed. Nothing was ever asked as to when my medication had been taken. Didn't even know that this was what the test was for until later on. Dr. stated it was for a vitaim D test but it was not. I found out this dr. and his college both lied to me about when one of my test results were in. Seen it on computer that it was in on the15th and they said it would not be in until the 18th. So I had to go back in again. These tests are not cheap and my insurance company thought I was terminally ill. Anyway if anyone can answer this I would greatly appreciate it. Thank for your time.

It relatively constant for the 1-6 hours after oxycontin is taken. See page 6. http://www.purduepharma.com/PI/Presc.../Oxycontin.pdf

I didn't look up Valium.

Many drugs start to break down within 20 minutes. Oxycontin is a slow release medication which means you should not cut it.

Pain management centers want to know if your taking the medication and/or taking what's prescribed.

With oxycontin, the effective dose is very dependent on your metabolism and your previous history. Where respiratory depression occurs is very individualistic.

You might ask the doctor why he did it.

There should not be any real difference taking it 2x/day, but you can't cut the oxycontin's.

The doctor will be able to account for when you last took the meds and how long you've been taking them. The longer you take meds, the more trace amounts build up in your system.

Your doctor should know when you started taking the meds. He should have asked what time you took the last dose.