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Half life of meds accumulate through the days?

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#1 Sertralinsomnia



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Posted 23 February 2017 - 02:46 PM

I was wondering, i dont know very much about half lifes of meds and steady states, etc. But i am curious on something, lets take zoloft for example, it has a half life of 24 to 26 hours. this would mean that if you take 50 mg today, tomorrow you would still have 25 mg in your blood, but tomorow you would take another 50 mg tablet, if the half life of the first pill is still there, it would mean that on the second day, we would have 75 mg of zoloft in our blood right? And then Since they are separate doses, they half lives would vanish indepedently, if so it would accumulate, i am missing something here, sorry for my curiosity., can someone explain how this reallly works?


According to what i understand this simple table shows that at the seventh day we would still have 98,8 mg on blood?  The numbers separated from / are the half lives of the pill from the day before.



DAY        1           2                                         3                                4                                                  5                                                        6                                                      7                              
DOSE    50     25/50 = 75 mg           12.5/25/50 = 87,5 mg    6.25/12.5/25/50 = 93,75 mg   3.2/6.25/12.5/25/50 = 93,95    1.2/3.25/6.25/12.5/25/50 = 98,2 mg   0.6/1.2/3.25/6.25/12.5/25/50 = 98,8 mg



So this would mean a dose of 50 every day would mean that a steady state is double the dose we take every day? If so that is way to huge. ????



Since i am only taking 2 mg a day, my steady state is in fact the double of it:


DAY           1         2         3            4                          5                                 6                                           7                              
dose           2     1/2   0.5/1/2   0.25/0.5/1/2  0.125/0.25/0.5/1/2    0.06/0.125/0.25/0.5/1/2    0.03/0.06/0.125/0.25/0.5/1/2 = 3.965 mg

Started zoloft 25 mg on October 2009. Started tapering May 2016 to june 2016, last week at 12,5 mg and quit

Crashed 23 january 2017, severe headache and panic (never had this panic all my life) next morning.Tried to reinstate with prozac 5 mg a day on 25 January 2016, bad choice, got arrhytmias and stopped.

Started propranolol 40 mg as needed on january 2014 - Didnt touch it anymore since January 2017
23/02/17 reinstated to 2 mg, had arritmia at night

24/02/17 changed dose to 0.5 mg - ok

25/02/2017 updose again 1 mg - ok.

26/02/2017 1 mg again, had full night insomnia, like my head was blowing up overstimulated - im sure was side effect zoloft

27/02/2017 skipped dose this day, my brain was overstimulated from last night, i calculated the half lifes from the days before until this day, and even on skipping this day i still had 1.375 mg zoloft on blood.

28/02/2017 stayed at 0.5 mg since then

I know i shouldn´t do this flutuations with the doses upon first reinstating, but at the same time i knew that the ammounts where still close to each other, and my body handled the reducing somehow. Truth said, i felt a little better as soon i reduced to 0.5 mg.


#2 scallywag


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Posted 23 February 2017 - 04:54 PM

I posted a chart with the half-lives for Cymbalta, the medication I'm taking, in this post in my intro topic.

This is not medical advice. Discuss any decisions about your medical care with a knowledgeable medical practitioner.
1997-1999 Effexor; 2002-2005 Effexor XR 37.5 mg linear taper, dropping same #beads/week with bad results
Cymbalta (brand name), 60 mg 2012 - 2015; 20 mg to 7 mg in 2016, exact doses and dates in this post;
2017: 6.3 (58 beads) Feb. 1; 5.6 mg (52) Feb. 22; 5.4 mg (50) Mar. 15; 5.1 mg (47) Mar. 25; 4.9 mg (45) Apr. 5;
Current dose: 4.5 mg (42) 2017-Apr-14
+ Supplements: fish oil (1500 mg EPA/500 mg DHA), Vitamins: D3, K2, C; Minerals: Mg, Se, Cr, I, V
scallywag's Introduction
Online spreadsheet for dose taper calculations and nz11's THE WORKS spreadsheet