Real benzo time to effect/duration

[quale]

So looking at the half lives of benzos seems to give no real indication of their actual time of action. The subjective effects seem to disappear much faster (tolerance effects?) in addition there seem to be bizarre issues with how long they take to kick in.
For instance several sites on the inet suggest lorazepam takes 2-4 hours to be effective while xanax only 1-2. What gives...is it a digestion thingy.
Also I have seen suggestions that lorazepam acts for significantly longer than xanax despite similar half lives. Is this true? What is the time of action. Is this related to slow digestion and mean that lorazepam is actually stronger than the dose equivalent charts suggests (i.e. if you somehow got emulsions and injected them lorazepam would be more than 1/2 as strong as xanax).
It would be nice if some people could post how long to reasonable effect on various benzos (primarily xanax, lorazepam..but others too if you know) and how long to max effect...as well as their subjective duration of action.
Yes I have already done searches on these topics...it is just the results are confusing...moreover in my experience the effects of benzos have either been subtle enough to make judgement difficult...or too strong to make memory easy.

 

[Effigy]

I cant really comment on much of what you said without some links to the sites that have info your talking about.
Duration of effects for me:
Xanax - 4 hours
Valium - 6 to 8 hours
Ativan - 8 to 10
Klonipin - 12+ hours <--obviously I prefer klonipin

 

[Harry@Piekarnia]

From: Clinical Handbook of Psychotropic Drugs, 4th revised edition, Bezchlibnyk-Butler et al. editors (Clarke Insitute of Psychiatry, Toronto), Hogrefe & Huber.
------------------------------------------------------------------------------------
Benzodiazepine i)Comparative dose ii)Time to peak plasma level iii)Half-life
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Alprazolam i .5 ii 1 - 2 iii 9 - 20
Bromazepam i 3.0 ii .5 - 4 iii 8 - 30
Chlordiazepoxide i 25 ii 1 - 4 iii 24 - 100 (hope you get the idea from here)
Clonazepam .25 1 - 4 19 - 60
Clorazepate 10 variable 1.3 - 120 * (unreliable absorption)
Diazepam 5 1 - 2 30 - 200 *
Estazolam 1 .5 - .6 8 - 24
Flurazepam 15 .5 - 1 40 - 250 *
Halazepam 40 1 - 3 30 - 96 *
Ketazolam 7.5 3.2 30 - 200
Lorazepam 1 2 4 8 - 24
Nitrazepam 2.5 .5 - 7 15 - 48
Oxazepam 15 2 - 3 3 - 25
Prazepam 10 2.5 - 6 30 - 100
Quazepam 7.5 1.5 39 - 120 *
Temazepam 10 2.5 3 - 25
Triazolam .25 1 - 2 1.5 - 5
* metabolites
This hasn't posted at all well so if you don't understand the idea check the orginal and a bit more at http://www.dr-bob.org/tips/bzd.html
Harry
[ 10 January 2002: Message edited by: Harry@Piekarnia ]
[ 10 January 2002: Message edited by: Harry@Piekarnia ]

 

[quale]

Thanks harry, I have seen that chart the problem is that half life doesn't seem to always correspond to duration. Specifically it seems lorazepam lasts significantly longer than alprazolam. Maybe this is because the time to peak plasma is longer and it is just absorbed slower.
I would really like a subjective account of how long lorazepam lasts.
[ 10 January 2002: Message edited by: quale ]