Opioids Morphine drug test cutoff levels!? How many mg to stay below 300 ng/ml!? Metabolism!?

[OxyChem]

So if someone were to have a drug test where the cutoff levels for morphine were 300 ng/ml, how much does that equate to in milligrams? From the conversions I've been doing (maybe I'm doing something wrong), if someone were to be prescribed 45 mg Morphine Sulphate per day, they would still test higher than 300 ng/ml!!! What's up with the cutoff levels for drug tests? I mean how many milligrams can someone use and safely stay below the cutoff levels (providing they likely use everyday)? What does 100mg Morphine equate to in ng/ml? Something seems off with my math. Any help is greatly appreciated!

Basically, there is someone who is prescribed 45 mg of Morphine per day and they take it exactly as prescribed yet they are always coming up higher than the cutoff levels for drug tests! Is 300 ng/ml really super low or what?

Does anyone know the average half-life for Morphine? I've seen widely varying information. Some info says 2-4 hours, some says 1.5-7 hours, another says up to 16 hours and so on. On average (I know metabolism, hydration levels etc affect this) how long does it take Morphine to be out of someones urine?

 

[sekio]

We don't allow drug testing questions on Bluelight, sorry.
I'll throw you a bone here though.

You can't easily convert milligrams of morphine ingested into a morphine urine concentration. You can guess wildly, but like you said, there are too many variables to consider to make it accurate.

The concentration levels for drug testing are meant to be pretty low, so you can pick up traces of drugs from a longer time ago than looking for an "active" concentration. A better metric might be looking at the blood levels at the same time each day.

Some quick math shows:
1500 mL (average daily urine output) * 150 nanograms per mL = 2.25 mg drug excreted per day (total) before you fail a drug screen.

The average half life for morphine depends on whether or not it is being taken chronically, in what amounts, and the renal status of the patient, in healthy people in "normal" doses (10-30mg) it is rapidly metabolised and excreted with a half life of about 2 hours.

The total persistence in body fluids I have no idea about, but using the usual rule of thumb (7 half lives) suggests that the majority of a morphine dose should be metabolized and excreted within 24 hours. Don't quote me on that though.