☼ nz11 climbs onboard

764 posts in this topic

Hi "Guys", yes I'm still drifting in and out.  Haven't had anything to say as been feeling a bit blah and have had trouble physically reading the posts (remembering what I've read before).  But I'm certainly up to doing a spreadsheet.  I like challenges!!!


Just looking at the posts, you'll need to let me know how it needs to be set up.



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Thanks cc


This is what we are after

1mg of rebox. = 1.6mg escita. = 3.0 mg paroxetine = 3.5mg prozac = 4.4 mg remeron = 8.6mg zoloft = 8.8mg nortriptyline = 10 mg anafranil

= 10.6mg amitriptyline = 13mg venlafaxine  = 30.3 mg wellbutrin = 34.9 mg trazodone


I want this as a spreadsheet such that every value becomes a variable whose value when entered calculates the values of all others based on the ratios shown.


This must be able to be done however the book im reading is excel for dummies and i might need the next book up 'excel for not so dumb dummies' or maybe 'excel for dumb and dumber'


I thought this could be done on one line using scenarios or something id love to see how it is done on excell. This should not be a difficult job for excel surely.


cc if you, songbird or any other excel whizzes can do it that would be good.awesome!


In the meantime ive given up on my dream version and  im working on a not so clever version..a longer one.

Edited by KarenB
corrected wellbutrin figure

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That should be pretty simple.  I might have a quick go at it later on tonight.

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How's this?  Let me know if it's what you wanted.  Did you want any other drugs added?


Edit:  I've just seen your recent post, I was busy!!!  I'll try again.

Edit #2:  I've just done a different one.

Edit #3:  Okay, they are attached now!


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thanks for your efforts cc you are a speedy cat!


What i enveseged is one row as per above but if someone is on say 150 trazodone say then you type in 150 under trazodone and then all the other numbers come in to line with that ratio and give equivalent dosages in the other drugs.


Im not clever enough to get the excel to do that  but what i have done is 12 columns one for each drug with the dosage as variable input then when entered all other figures are provided for the other drugs.


Correction to the above ratio calcs....wellbutrin should be 30.3 Not 33.4 as posted in 437 and 426.

348.5/11.5 =30.3 Not 33.4 as i originally posted.

So perhaps the first thing is crosscheck my numbers in post 437.

While i am correcting errors...boy its been a bad day...thought i would apologize to the mods for my stuff up in the Tobin case.

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Okay, other than using a macro (which I am fairly new at) or very complicated formulae (which would be way passed my abilities), this was the only way I could think of doing it.  Someone might come up with something better.  I haven't checked the numbers but all of the formulae are in place so you can add the ones that are missing.  Eg, if you type 10 under Escitalopram it will put 10 under the Escitalopram heading and calculate the others accordingly.



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I've had a go at a spreadsheet.  You can enter a dose in a yellow cell and it calculates the comparable dose for the other meds in the other columns - doses based on your earlier posts.  It's very late and my brain has been noticeably absent today (got an appointment time wrong, left my cellphone at home, etc.) so test it out and see if it actually works correctly.


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Very professional Songbird ...

I can confirm i have cross checked all Songbirds numbers and the spreadsheet is perfect.

It has even taken account of my wellbutrin corrected figure.

Good going SB.

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While on the topic of spreadsheets what do people think of this for a spreadsheet you think this is useful for anyone.


A spreadsheet that can answer these questions.


'what has been my average monthly taper % if i input my start dose and my now current dose ? 


and, how many (4 week) months do i need to taper for to get to 1mg  if i input the desired  taper % and current dose ?

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 Songbird spreadsheet has been excellently done using this info as source ratios (calc by me rounding to 1 decimal place with calculator)


1mg of rebox. = 1.6mg escita. = 3.0 mg paroxetine = 3.5mg prozac = 4.4 mg remeron = 8.6mg zoloft = 8.8mg nortriptyline = 10 mg anafranil

= 10.6mg amitriptyline = 13mg venlafaxine  = 30.3 mg wellbutrin = 34.9 mg trazodone



Hence when one enters 11.5 for reboxetine it is not exact with the below numbers from the study ....this is due to rounding ...there is very little in it...within 1 unit.


  • reboxetine 11.5 mg/day
  • escitalopram 18.0 mg/day
  • paroxetine 34.0 mg/day
  • [prozac 40.0 mg]
  • mirtazapine 50.9 mg/day
  • sertraline 98.5 mg/day
  • nortriptyline 100.9 mg/day
  • clomipramine 116.1 mg/day
  • amitriptyline, 122.3 mg/day
  • venlafaxine 149.4 mg/da
  • bupropion 348.5 mg/day
  • trazodone 401.4 mg/day

I have tweeked songbirds spreadsheet a little by getting the spreadsheet to calc the above source ratios to many decimal places and the result is that when 11.5 is entered for reboxetine in the speadsheet the exact numbers given by the study are now reproduced exactly.



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and, how many (4 week) months do i need to taper for to get to 1mg  if i input the desired  taper % and current dose ?


I think my doseweights spreadsheet can do this.  If you enter the taper % and starting dose, and look at the row number where you see 1mg and then take away 3 for the top three rows.

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Thanks SB ill have a look at it.

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Two very long days later and one long night ..spent peppering google with questions.....he finally emerges totally exhausted from his mancave....i believe the mission has been  accomplished!!!



I present to you the nz11 version of The Dose equivalent calculator...its a great one liner!


As they say in the states.



[.. translated into kiwi "Sweet as bro, sweet as ! "]



I think i need a few days off....time to head up the Cape for a spot of fishing.

Dose Equiv. calculator nz11 version 28 Jan 16.xlsx

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As they say in the states.



[.. translated into kiwi "Sweet as bro, sweet as ! "]



Chur, NZ :P

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Bees Knees NZ.  Except it's flawed. There is a typo on the first line: is dug s/b drug.  Catch your breath and start again. LOL


This is going to be very helpful, thanks all for the effort.

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Hey Brass you nearly gave me a heart attack.


You are right. i spelt drug wrong. lol (oh shite) . Clearly i was  too fixated on the beautiful faultless figures!!

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Two spelling errors corrected. One capital letter, and one comment added. Editor acknowledged!

Thunderbirds are go!

I present to you the nz11 version of The Dose equivalent calculator...its a great one liner!

Dose Equiv. calculator nz11 version 28 Jan 16.xlsx

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Power up Rangers!!!!


Now about those beautiful flawless figures, nudge, nudge, wink, wink.  I think I had better shut up before I get in too much trouble.

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I just typed this out for another member so i decided to put it here as well 


Its taken from Whitakers Anatomy book


on Xanax (alprazolam). he writes:


Xanax was approved by the FDA as an anti-anxiety agent in 1981, and then Upjohn set out to get it approved panic disorder, which had been newly identified as a discrete condition for the first time in DSM III (1980).


As a first step it hired former NIMH director GeraldKlerman to co-chair its "steering committee" for the testing process and it paid Daniel Freedman editor of the Archives of General psychiatry to be an assistant to its division of medical affairs.


This was just part of the company's efforts to co-opt academic psychiatry: "The most senior psychiatrists in the world were flooded with offers of consultancies" from Upjohn, said Isaac Marks, an expert in anxiety disorders at the Institute of psychiatry in London.


Klerman and Upjohn designed Upjohn's cross national collaborative panic study in a manner that could be expected to produce a poor placebo response.


Patients who had been on benzo's were allowed into the study, which meant that many in the placebo group would in fact be going through the horrors of benzo withdrawal, and thus could be expected to be extremely anxious during the first weeks of the trial. Nearly one fourth of the placebo patients had traces of benzos in the blood when the treatment period began.


Benzos are known to work quickly, and that proved true in the study. At the end of four weeks, 82% of the xanax patients were moderately improved or better versus 43% of the placebo group. However during the next four weeks, the placebo patients continued to improve, while the Xanax patients did not, and by the end of the eighth week there was no significant difference between the groups on most of the rating scales, at least among the patients who remained in the study. The Xanax group also experienced a variety of troubling side-effects: sedation, fatigue, slurred speech, amnesia, and poor coordination. One of every 26 Xanax patients suffered a serious reaction to the drug, such as mania or aggressive behaviour.


At the end of eight weeks the patients were tapered from the medication for four weeks and then followed while medication free for another two weeks. The results were predictable. 39% of those withdrawn from Xanax deteriorated significantly, there panic and anxiety skyrocketing to such an extent they had to start taking the medication again. 35% of the Xanax patients suffered rebound panic and anxiety symptoms more severe than when the study began, and an equal percentage suffered a host of debilitating new symptoms, including confusion, height and sensory perceptions, depression, feeling that insects were crawling over them, muscle cramps, blurred vision, diarrhoea, and decreased appetite, and weight loss.

In sum, at the end of 14 weeks the drug exposed patients were worse off than the placebo group: They were more phobic, more anxious, more panic stricken, and doing worse on a 'global scale' that assessed overall wellbeing. 44% had been unable to get off the drug, on their way to a lifetime of addiction. In every way the results painted a powerful portrait of the  benzo trap:  This was a drug that worked for a short time , then its efficacy over a placebo petered out and yet when patients tried to go off the drug, they became quite sick and many couldnt kick the habit. The first few weeks of relief came at a very high long term cost, with those stuck on the drug - as previous benzo studies had shown - likely to end up physically, emotionally , and cognitively impaired." 

The Upjohn investigators published three articles in the Archives of Gen psychiatry in May 1988, and anyone who carefully reviewed the data could see the harm caused by  Xanax.


In order for Xanax to be successfully marketed, Upjohn needed its investigators to draw a different sort of conclusion, and so they did, particularly in the abstracts of the three articles.


First, they focus their attention on the four-week results (rather than the eight week outcomes at the end of the treatment period), announcing that xanax was found to be effective and well tolerated. Next they noted that 84% of the Xanax patients had finished the eight week study, which was evidence that "patient acceptance of Xanax was high."


Although their Xanax patients regularly exhibited such problems as "slurred speech, amnesia" and other signs of "impaired mentation", they still concluded that the drug had few side-effects and is well tolerated.


Finally, while they acknowledge that some xanax patients fared  poorly when the drug was withdrawn, they reasoned that it had been used for too shorter period and the withdrawal done too abruptly. We recommend that patients with panic disorder be treated for a longer period, at least six months, they said.


In London, Isaac Marks and several of his colleagues at the Institute of psychiatry subsequently pointed out how transparently ridiculous this all was.


In the letter to the Archives of General psychiatry they observed that since the Xanax patients "were in a worse state than patients receiving placebo" at the end of the study, the finding by the Upjohn investigators that the drug was effective and well tolerated can only be seen as" biased and arguable."


The entire affair, Marks subsequently wrote, is a classic demonstration of the hazards of research funded by industry.


Yet the fact that the Xanax patients came to such a bad end, with many on a path to a lifelong addiction, did not deter Upjohn, Klerman, the APA, and the NIMH from touting Xanax's benefits to the American public.


The same marketing machinery that had made Prozac a bestseller was rolled out again.


Upjohn sponsored a symposium on the APA's 1988 meeting where the "expert panel" highlighted the four-week results.


Robert Pasnau, who had been head of the APA in 1987 sent a  glossy booklet on the Consequences of Anxiety to APA members, an "educational" effort paid for by Upjohn. Both Shervert Frazier and Gerald Klerman penned a "Dear Doctor" letter that Upjohn included in the promotional literature it sent to doctors about Xanax as a treatment for panic disorder.


Upjohn also gave 1.5 million to the APA so that it could mount a DART - like campaign to educate psychiatrists healthcare workers in the public about panic disorder which was said to be underrecognized and undertreated.


Finally the the NIMH chipped in to identifying panic disorder as a priority concern sponsoring a conference in 1991 on it, with its panel of experts designating "high potency benzos" this would be Xanax - as one of the two" treatments of choice."

The FDA approved xanax as a treatment for panic disorder in November 1990, and many newspapers and magazines ran the usual features.


IN A PANIC? HELP IS ON THE WAY, a Saint Louis Post-Dispatch headline announced. Treatment, the paper said, helped 70 to 90% of those with the debilitating condition, which afflicted 4 million adults in this country.


The associated press explained that a  "biochemical malfunctioning in the brain is believed to be one of the causes of panic attacks. Xanax can block the attacks by interacting with several different systems in the brain."


In the Chicago Sun Times Dr John Zajecka at Rush Medical college in Chicago announced that "Xanax is the fastest acting and least toxic" of medications for this disorder. Once again a very effective safe drug had arrived on the market, and in 1992, Xanax became the fifth most frequently prescribed medication in the United States.


Whitaker Anatomy pg295- 299

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Was reading this from the journals section this morning...




Clinical Neuropsychiatry Journal of Treatment Evaluation. 2007;4(42):61–75.
The adult SSRI/SNRI withdrawal syndrome: A clinically heterogeneous entity.
Kotzalidis G, Patrizi B, Koukopoulos A, Savoia V, Gaia R, et al.
Full text at http://www.clinicaln..._kotzalidis.pdf




Decided to comment on this in my own thread as i do sometimes (but not often) get a bit cynical.


Like so many of these things they start off so promising especially  with statements like,


Various reports and controlled studies show that, in some patients interrupting treatment with selective serotonin re- uptake inhibitors or serotonin and noradrenaline re-uptake inhibitors, symptoms develop which cannot be attributed to rebound of their underlying condition.


But then they become very disappointing very quickly.

These symptoms are variable and patient-specific, rather than drug specific, but occur more with some drugs than others.

Are they inferring the patient is the problem and not the drug?


But i do like this statement ..

It has been claimed that the shorter the half-live, the more a drug is likely to induce a withdrawal syndrome; however, this is not supported by data.



This is what they call a gradual [slow] reference for it maybe its their guess or they are just reading the writing on the wrappers who knows.




The above schedule is to be intended as the minimum requirement for avoiding the development of a withdrawal syndrome. It does not guarantee that the syndrome will not develop.


Patient and doctor should closely collaborate in defining the exact timing for discontinuation. [ingenious -this is pharma's king hit on guaranteeing repeat business]


The British National Formulary (BNF) recommends to taper-off in at least four weeks to obtain minimal SSRI/SNRI withdrawal symptoms (British National Formulary 2000); this rule must apply to venlafaxine, fluvoxamine, paroxetine, and sertraline, while fluoxetine might constitute an exception, as the time course and pattern and severity of withdrawal differs from those of other SSRIs and SNRIs (Rosenbaum and Zajecka 1997).


Why is it we always get the 'minimum' or 'least' requirement why cant we get the 'normal requirement' or 'safest' requirement or the 'most extremely slowest requirement' for once.


Tapering rate is affected by the type of antidepressant, treatment duration, past history of withdrawal symptoms, and the need to withdraw the drug (Haddad 2001).

Dont know if 'type' has much to do with it - there appears to be very little difference between them.


Just been reading Irving Kirsch in his book the Emperor's new drugs where he says,


"The lack of difference we found between one class of antidepressants and another is now a rather frequent finding in antidepressant research" p12


his source document for this was John W Williams, Jr, et al, 2000.  Obviously this was not read by Haddad.


Don't forget this was in 2000 yet in 2016 we have doctors thinking 'oh its all about finding the drug thats right for you " so we see switch after switch after switch in order to relieve relapse withdrawal symptoms.


Since fluoxetine is less associated with withdrawal syndromes in the immediate aftermath of suspension, one possible strategy is to switch from other SSRI and SNRI antidepressants to fluoxetine, and then taper-off gradually (Haddad 2001), since the latter was shown to suppress withdrawal symptoms of both SSRIs and venlafaxine (Giakas and Davis 1997). Fluoxetine is more appropriate therapeutically in patients who tend to quit treatment abruptly or in those who miss doses, because it is associated with later onset of withdrawal symptoms, that tend to be milder and occur in less patients; this suggestion has been based on the longer half-life of this drug and the smoother, slower disappearance from blood (Zajecka et al. 1998), but a clear demonstration of this hypothesis is lacking.


So the reasons for prozac bridges are not fact then.

Personally i see the prozac bridge as doomed to fail every time because look how the prozac is being tapered! Its a complete disaster. Doctors dont have a clue.

Doctors think that oh no wdl symptoms with prozac ok we'll just switch and than after a month you can stop the prozac (CT or within a month) and all is fine. I cant get over how many failed prozac bridges or variations thereon are finding their way to sa at the moment.


I wonder if Giakas and Davis have any conflicts of interest?


Hence, it is recommended to discontinue such drugs with an extremely slow tapering schedule, especially if the patient had developed a withdrawal syndrome when he/she discontinued another drug, antidepressant, antipsychotic or if he/she is a substance user/abuser.


How come 'extremely slow tapering is never defined.....what is it then 2 months instead of 1 month?

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Been looking into this today as well. 

I think i understand it now.



                           Half Life                                                                                                                          Steady state reached  

Reboxetine      13 hrs                                                                                                                                            5 days 

Escitalopram   27-33 hrs                                                                                                                                       7 days  

Paroxetine       21 hrs (range 3-65hrs)                                                                                                                  10-14 days          

Fluoxetine       1-3 days; 4-6 days long term use; active metabolite 16 days.                                          30-60 days (4-5 weeks)   

Mirtazapine     20-40 hrs                                                                                                                                    3-6 days

Sertraline         26 hrs                                                                                                                                         7 days    

Nortriptyline   18-93 hrs                                                                                                                                    4-21 days  

Clomipramine  12-36 hrs                                                                                                                                  3 weeks     

Amitriptyline   8-51 hrs                                                                                                                                    2-6 days     

Venlafaxine     4 hrs ; active metabolite 10hrs                                                                                                 3 days        

Bupropion       12-30 hrs                                                                                                                                  8 days         

Trazodone       4-7 hrs                                                                                                                                      4 days         

citalopram       35 hrs                                                                                                                                       7 days          


Info taken from this and google.                                                              


What is half life.

Half life. This is the period of time required for the concentration or amount of drug in the body to be reduced by one-half.    


What is Steady State

A condition in which the introduction of a substance just keeps pace with its removal so that all concentrations, remain constant.


So how does steady-state work ?

Well let’s consider Paxil (paroxetine) half life 21 hours (range 3 - 65 hours).

Let’s just assume half - life is 2 days (say).

This means, if you take a 20 mg tablet it will take 2 days to get to 10 mg (half the dose) in the blood.

Or put it another way the body will eliminate 5 mg per day.

So it will look like this:

Day    In the blood                                                                      Total

1.         20 mg                                                                                      20

2.         15mg,  20mg                                                                           35

3.         10 mg, 15 mg, 20 mg                                                              45

4.          5 mg,  10 mg, 15 mg, 20 mg,                                                 50

5.          –         5 mg, 10 mg, 15 mg, 20 mg                                        50

6.           –        –          5 mg, 10 mg, 15 mg, 20 mg                            50


From Day 4 onwards there is now a 'steady state' amount of 50 mg in the body


Question :So is a person on 20 mg  really on 50mg ?

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Since the dose equivalence spreadsheet i cant get over the fact i was on a drug paroxetine that is more potent mg:mg than prozac.


I would have run a mile if I thought I was taking anything similar to or worse than Prozac!


I didn't know anything about drugs at the time but I did know that prozac and valium were to be avoided.


Watch this space will be posting a new spreadsheet soon.

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I'm learning a lot on this thread lately ... thanks NZ

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:) Thanks KB.

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I actually did a spreadsheet that worked out days to steady state etc. - it was quite a few years ago, I don't know if I still have it somewhere.

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That would be a good resource to have SB.

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That's some excellent information NZ11.  Now we can tailor our RI advice a little more specifically when people ask "how long" or they want to make changes after only two days.

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Thanks Brassmonkey.

Yeah its interesting isnt it there appears to be quite some variation in the steady states.


Oh dear the race is on to come up with  a spreadsheet for steady state....just when i am in the middle of work on a different spreadsheet.


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Later ...

.....i think we don't need a spreadsheet for steady state.


The question to ask is what is the relationship between the half life and the steady state?

(Recall: Steady state is the time it takes for a constant amount of drug to exist in the body.)


That is, given the half life what is the steady state.


                                                    Its as simple as this:


                                                      Steady State (days)  =  2 x half life (days).  




Let :

d = the start dose

h = half life (days)

y = how much you lose per day = (start dose divided by 2) divided by the half life =  d                         -------- (1)


So the accumulation of drug follows an arithmetic progression as follows:

d, d-y, d-2y, d-3y, d-4y, .......etc


such that the general term is T(n) = d - (n-1).y


Steady state exists when  d - (n-1).y = y ; (i.e. when the nth term = y )


Solving for n gives: n = d/y


Substituting equation (1) above for y gives 


n = d/ (d/2.h)

  = 2h


Hence,    steady state (n) = 2x h



Question: Why the heck is the above list of half lives and steady states showing (time to reach) steady states that are much longer than two times half life ?

Am i missing something here?

eg paxil; half life of 2 days say, manual calctn above shows 4 days to steady state, the formula 2 x half life gives 4 days to steady state, yet the documented steady state is 10-14 days ???

Songbird you out there? 

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Is a spread sheet really necessary, I think just the list like you have is sufficient.


There is probably some metabolic variable that isn't taken into consideration in your formula.  I noticed that one of them claims  "Fluoxetine   30-60 days (4-5 weeks) "  5 weeks is 35 days so I have to question the accuracy of their data.

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Brass,  you could well be right there. There may be another variable we don't know about.


Oddly though the prozac may be one of the more accurate ones.


The half life appears to be 16 days+ ? (My understanding is that its extended because of the active metabolite it creates).


Using the formula gives a steady state of 32 days which just sneaks in according to the research data. (range of 30-60 days)

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I found my spreadsheets but at first glance can't understand them.  I'd probably have to spend some time figuring out what the heck I did and what it all means.  The data I used was based on a graph I found from a study that was comparing their measurement method to a reference graph.  The graph showed plasma concentration after a single 20mg dose, with half-life of 21 hours.  It isn't quite as simple as half-life because the plasma concentration changes at different rates over time, i.e. it isn't linear.  I extrapolated the data from that graph, which is simplistic because the graph was for a single dose, but repeated doses could change the rate at which the drug is cleared.  So I just treated my calculations as an approximate ballpark kind of deal.


The reason I did it was to compare plasma concentration rises and falls with a daily dose, versus a twice daily dose (i.e. half the daily dose twice a day).  Some of you may know that I switched to a twice daily dose for this taper.  The graph showed a lower average plasma concentration, but a much smaller range, i.e. the level of available drug doesn't go up or down as much.  My very non-scientific spreadsheet showed steady state ten days after the first dose.

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Thanks SB


It isn't quite as simple as half-life because the plasma concentration changes at different rates over time, i.e. it isn't linear.

Yes i think this is what BM is saying, basically there are other variables.

yep sounds like i have over simplified it.

But doesn't that mean the half life may not be the true half life by defn.


My very non-scientific spreadsheet showed steady state ten days after the first dose.

Sounds like you have been very scientific to me because 10 days is exactly the time to steady state for paroxetine.

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The definition of half life would remain the same but it would mean that in practice the actual half life is a unique individual thing.  You can have a laboratory half life in vitro and with models, but that would be lacking the additional parameters of individual metabolism, absorption rates, kidney function and the like.  That would be why they state a range and not a hard figure. Also those individual parameters would variable depending on time of day, time of month, current health concerns, stomach contents and a lot more.  Not to mention interactions with other drugs, supplements and the like.


That's why I think a simple chart is all that is necessary.  On line we can only give a ballpark estimate at best, but knowing that each drug has an individual time frame makes that ballpark a lot smaller.

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Also the half-life is based on the dose, so for a single 20mg dose they figured out a half-life of 21 hours (I guess maybe this is an average, as like Brass said, individual results could vary a lot).  But the half-life for other doses could be different.

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So on a smaller dose half-life is probably less, or?

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