dancesintherain Posted April 17, 2012 Share Posted April 17, 2012 Can someone explain half lives to me? I am curious when a med would be out of my system after I take it...particularly with the ativan and geodon. (I can tell when ive forgotten a lamictal dose, so i assume it is exiting my system then.) One of my pdocs questions today was whether i felt the effect of geodon throught the entire day (i take it at night), so i was wondering if this was the reason why. Link to comment Share on other sites More sharing options...
Eden Posted April 17, 2012 Share Posted April 17, 2012 Half life is the amount of time it takes for half of an allotted amount to leave your system, if the half life was one hour and you had 8mg in your system it would be 8mg, 4mg an hour later and 2mg an hour after that. Hope this answers your question. Link to comment Share on other sites More sharing options...
ManWitPlan Posted April 17, 2012 Share Posted April 17, 2012 It takes 5 half lives for a drug to leave your system. Link to comment Share on other sites More sharing options...
dancesintherain Posted April 18, 2012 Author Share Posted April 18, 2012 Hmm, so if geodon has a half life of 7 hours...I should feel the full 20mg at 8pm, 10mg at 3am, 5mg at 10am, and only 2.5mg at 5pm? No wonder pdoc was curious if I felt the effect all day... Link to comment Share on other sites More sharing options...
tryp Posted April 18, 2012 Share Posted April 18, 2012 Hmm, so if geodon has a half life of 7 hours...I should feel the full 20mg at 8pm, 10mg at 3am, 5mg at 10am, and only 2.5mg at 5pm? No wonder pdoc was curious if I felt the effect all day... That is one reason why it is important to take your meds every day and to give them time to build up in your blood. That's what would happen if you took a single dose, but if you have been taking it regularly, it does build up a bit. Since you are taking more doses over that time, your levels should never really dip that low. Link to comment Share on other sites More sharing options...
notfred Posted April 18, 2012 Share Posted April 18, 2012 The time to clear a med from your system is about 5 half lives. Link to comment Share on other sites More sharing options...
dancesintherain Posted April 18, 2012 Author Share Posted April 18, 2012 That is one reason why it is important to take your meds every day and to give them time to build up in your blood. That's what would happen if you took a single dose, but if you have been taking it regularly, it does build up a bit. Since you are taking more doses over that time, your levels should never really dip that low. I think im almost there...is the idea that if it would take 5 half lives to flush it out and the half life is 7 hours, it would really take 35 hours to lose it completely...so theres always going to be some lingering from the prior day? Or something like that? Link to comment Share on other sites More sharing options...
tryp Posted April 18, 2012 Share Posted April 18, 2012 Yes. So suppose that Geodon has a halflife of 7 hours and you take 20 mg 2x per day. You take your first dose at 8 pm, giving you 20 mg in your system. If you take your morning dose at 10 AM the next morning, two half-lives will have elapsed, so there will be 5 mg in your body at the time when you take the next dose, giving you a total of 25 mg. I used to know a really great website that would calculate your blood levels for you based on how long you had been taking the medication, the dose and the time since last dose but I can't seem to find it. Anyway, the amount in your blood doesn't rise indefinitely - eventually you level out - but you don't usually completely clear the old stuff by the time you take another dose, either. I'm sure the actual amounts are more complicated, since your body is pretty complicated and there are sometimes metabolites and other stuff running around. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.