1. Dear Drugs-Forum readers: We are a small non-profit that runs one of the most read drug information & addiction help websites in the world. We serve over 4 million readers per month, and have costs like all popular websites: servers, hosting, licenses and software. To protect our independence we do not run ads. We take no government funds. We run on donations which average $25. If everyone reading this would donate $5 then this fund raiser would be done in an hour. If Drugs-Forum is useful to you, take one minute to keep it online another year by donating whatever you can today. Donations are currently not sufficient to pay our bills and keep the site up. Your help is most welcome. Thank you.

Drug info - What is "terminal elimination half-life"?

Discussion in 'Opiates & Opioids' started by JasNod, May 20, 2012.

  1. JasNod

    JasNod Newbie

    Reputation Points:
    Apr 8, 2012
    from U.S.A.
    What does terminal elimination half life mean? Is it when half the drug degrades like terminal half life, or is it when enough half lives have passed that the drug is fully dissintegrated? I read: "fentanyl has a terminal elimination half-life of 219 minutes". Sorry for any typos I'm on a phone.
  2. Tigey

    Tigey Palladium Member

    Reputation Points:
    Nov 5, 2011
    from Australia
    Good question. To quote:

    (full document attached).

    As best as I can explain it, after peak plasma concentration of a drug, the drug starts exiting your system.
    At this point, the drug is exiting fast (units of flow). At a point called the terminal phase, the drug starts exiting at a steady rate, and this gives the 'curve then straight line slope' look familiar to you if you've seen a drug in blood plasma concentration graph before. The terminal elimination half-life is the time it takes to lower the amount of drug in plasma by half (divide it by two), after it has reached steady-state absorption or steady-state plasma clearance/distribution. In other words, there are three limiting factors in how fast your body can absorb drugs, and this measure gives you a good baseline for re-dosing etc.

    read the full text for a better explanation - it's 3.30am here!

    hope that helps,


    Attached Files: