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calculating drug detection times

Discussion in 'Drug testing discussion' started by rainmaker42, Nov 5, 2011.

  1. rainmaker42

    rainmaker42 Newbie

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    Swim took 40 mg of oxycodone 48 hours before a probation drug test. Hopefully it is not even tested for but in case it was, Swim calculated if it was possible to pass but the math is not adding up to to the standard detection time given of 3-4 days.

    Can anyone correct the math here? So 40 mg of oxy is 40 million nanograms. The half life is 3 to 4.5 hours and lets do worst case and choose the max half life so you divide the 40 million by 2 every 4.5 hours. Now the detection limit is 100ng/ml. If when you urinate your amount of pee is 12 oz then that would be 360 ml.

    That means after 45 hours the level of oxy would be 39,062.5 total. Divide this by the 360 ml present and the ng/ml level is 108. But only half of your total would be metabolized so that means anyone should safely be at 54 ng/ml. So shouldn't the detection time be 2 days?

    Swim worked out twice and went to the sauna afterwards. He also drank 120 oz of water in the couple hours before the test and his sample given was his 4th pee of that couple hour period. If the math above is correct than there is no possible way Swim could have failed but he is nervous because he is afraid he is leaving something out of his calculations.
     
  2. rainmaker42

    rainmaker42 Newbie

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    no math nerds here to confirm or correct me?
     
  3. Solar Supernova

    Solar Supernova Newbie

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    I don't believe the math is as simple as that, but based on what you've told me about taking 40 mg once and drinking water, sweating it out, two days should be good because any form of oxycodone is out quicker than most other opioids. The actual formula is much more complicated to figure the levels that will be in your system at any given time. It's some kind of logarithmic scale, not as simple as dividing by 2 over and over. And as for a probation drug test, I can almost guarantee it was tested for even if it was a basic 5-panel quick cup. If it was going to a lab, you may have more to worry about.
     
  4. salgoud

    salgoud Newbie

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    Having taken many math and higher math courses your math is correct. Unfortunately, that's not what the problem would be. Yes, usually opiates have a cutoff point at 300ng/ml of urine, thus let me double check it for you: 40mg of oxycodone taken 48 hours prior to a urine drug test. So first one must know if it was an extended release formulation or immediate release formulation. Say it was the worst case scenario, then let's go with the former. 40mg is 40 x 10+6ng. It should take 10 half-lives to get the drug safely below the cut-off range.

    (To give you a little background on me, I have a BS in Chemistry and took many math, algebra, Calculus I, II, III, Process Simulation, etc in Engineering School and I tested UA's at the Colorado Department of Health in the toxicology lab for many years.)

    Thus around 45 hours to be at around 11ng/ml. However, since most people metabolize drugs at a different rates and we are using the worst case scenario, 4.5 hour half-life. If one would take 40mg of immediate release oxycodone two days prior to given a drug test and they got some type of physical exercise and drank the normal amount of water one should drink in a day, 6-8 oz glasses at least 6 times a day, or 48 oz of water a day. Then I wouldn't worry about it too much if it was a one time thing. Drugs have a way of being absorbed in the fatty tissue and I believe oxycodone does not to a great extent, also orally it has a high bioavailability of 87%. So initially if done orally, one would have to multiply the 40 x .87 = 34mg oxycodone.

    You are right about the time to make the oxycodone inactive. However, oxycodone is made into an inactive glucuronide such as morphine and other drugs. These drugs undergo no further metabolization and these are what are detected for opiates and semi-synthetic opiates, the glucuronides. Yes oxycodone will metabolize to oxymorphone to a degree then factor from the 4.5 half-life, what the half-life is of the converted oxycodone to oxymorphone. You must take that into account. The UA test for oxycodone checks for the drug itself and the metabolites. However, just because it takes oxycodone 4.5 hours, for half of it to become inactive, you must then understand how long it takes the body to rid itself of oxycodone and oxymorphone glucuronides. It is a non-exact science and you really can't go by the half-life alone. You must take into account how long it takes the metabolites to deposited in the bladder. The glucuronides do not cross the Blood Brain Barrier and thus inactivates the drug by glucuronidation. Then usually the factor on ones lifestyle (eating habits, exercise habits, drinking water, etc), would have to be factored in and would depend on how fast these detectable inactive metabolites are excreted.

    Personally, I would think if one took 40mg of oxycodone 48 hours prior to a urine test, it's cutting it close, but with normal activity and drinking water on a regular basis, I would doubt one would be positive for opiates if it was a one time deal. The problem arises in the metabolic route the drug takes and when the body has inactivated the drug for excretion, then how long it take these still detectable metabolites to be excreted out of the urine. Let us know if the UA came back positive or negative for opiates. That would be interesting to know. Good luck.

    salgoud
     
    Last edited: Jan 13, 2012
  5. TurboGolf

    TurboGolf Newbie

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    interesting.. i need some help

    can someone tell me how to calculate the "above the 2000ng/ml limit" on the opiate part of a drug screen?? like i saw the first post the person divides by 360? but whats with the 'Million' nanograms .. ??

    let's say there is no mistakes or factors to effect the ruels and the below is the precise information..

    for example: if someone induced 80 ML of Oxycodone and the half life is 4 hours and there's 60 hours until testing , how do i calculate the NG/ML mark? anyone? thanks
     
  6. salgoud

    salgoud Newbie

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    A 2000ng/ml cut off level is fairly high. Where I worked we used the 300ng/ml cut off point for opiates. 1g is 1,000,000,000ngs. 1mg is 1,000,000ngs. So they are trying to detect an opiate level above 2000ng per ml of urine. You also must be talking about 80mgs of oxycodone, not unless you are taking a liquid form, such as Roxanol, and it contains 1mg/ml. Then, did you just take one 80mg pill, or have you been taking it for awhile. Drugs do build up in ones body after taking them for a period of time.

    Metabolization of a drug is not an exact science since we all metabolize drugs at different rates. However, if a person took an 80mg OxyContin and the half-life was 4 hours and you had 60 hours, the oxycodone would be 15 half-lives, reducing, mathematically, the oxycodone to 0.0024mg or 2400ng of oxycodone. Then that's all I can say, I have no idea how much of the metabolized drug will be in your bladder. However, flushing with water, exercising till you sweat can help. Take Vitamin B Complex to give your urine color. Do not add water to the sample, drink plenty of water and pee as many times as possible before the test.

    This is not this easy to figure out by the half-life of a drug alone. The oxycodone metabolizes to oxycodone glucuronide and oxymorphone, which then turns into oxymorphone glucuronide. This is what they look for, not just oxycodone. The glucuronide does not cross the blood brain barrier and is inactivated. This is how the body rids itself of what it believes are toxins and is removed from the blood by the kidneys and liver and excreted in the urine and feces. So you can tell how long a drug may be effective, but one can only approximate how much of the glucuronides will be in the urine. Personally, with such a high cut off point, you may be OK, but I will not speculate what amount of oxycodone metabolites will be in your bladder.

    So many other factors are involved that one cannot deduce if you will be above or below the cut-off point by half-life alone. This much is true, you will still have 2400ng of unmetabolized oxycodone in your blood stream assuming you metabolize oxycodone in 4 hour half-lives. Length of use, diet, exercise, water intake, and many other factors must be considered. Questions must be raised on how long it takes the oxycodone to partially metabolize to oxymorphone, then what is the half-life of it is and the length of time for the body to inactivate both into the glucuronides. All you can do is exercise like hell, sweat it out, piss it out and cross your fingers. I tested UA's, I did not major in Biochemistry of the human body. I did what you asked, but that does not mean you will pass the UA. Too many factors involved that are giving me a migraine. I hope you pass, if you really want a clean UA go by the detection times. The best way to have a clean UA is not to use while on probation, parole or trying to gain employment. Good luck.

    salgoud
     
    Last edited: Jan 19, 2012
  7. peacelovedrugs

    peacelovedrugs Newbie

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    I'm curious, everyone speaks taking one pill, half life's, etc. But what if a person has been taking oxy for years. How do you estimate half life. Would it be from the last pill or and adding up of pills over a period of time.
     
  8. brutal_angus

    brutal_angus Newbie

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    Someone would have to add up all of the mg from each dose..
     
  9. Pseudovoyager

    Pseudovoyager Silver Member

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    Welcome to the forum! Nice to have you here, brutal_angus :)

    In reference to your post, I think that peacelovedrugs was asking what the concentration of oxycodone/its metabolites would be in a long-term user, not so much how much of the drug, milligram for milligram, has been taken over the course of one's opiate career.

    In which case...as far as I know it would be from the last pill. THC stays in your system so long because it's a highly lipid-soluble substance, but that's not the case with Oxycodone. If anything, I could see a long-term user (as in years) possibly needing an extra day or two for the drug to clear, but certainly not any more than that.

    I could be wrong here, however. That is my educated guess on the matter. Feel free to correct me if anyone finds fault with my statements above. :)

    Oh, and peacelovedrugs, the amount of time a drug is taken shouldn't affect its half-life. It can affect its total elimination time, both through direct (i.e., accumulation of the drug in fat cells) and indirect (i.e., modified liver enzyme levels due to chronic use) means, but the half-life of the drug itself will remain the same.
     
    Last edited: Nov 18, 2013
  10. whatstheproblem

    whatstheproblem Newbie

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    I would start another thread for whatever you guys want to discuss seeing as this one is almost 2 years old. just a reminder to check the dates.