how many half lives?

[pandoraisbored]

I'm not sure where to pit this question. It's about something I read in a thread that I can't figure out how to reply to.

The thread was listing the interactions between various anti-depressants and drugs. It stated that the half life of Anafril is 22-84 hours.

My question is how many half lives would a person have to wait while abstaining from an anti-depressant in order to ensure that a reaction does not occur?

 

[PriestTheyCalledHim]

Talk to your doctor that prescribes you the medication about the half life of it, about any other drugs you take, and about any drug interactions.

 

[d1nach]

Do you mean adrafinil. I take modafinil the active metabolite of adrafinil

Modafinil has two isomers* might be wrong word

+modafinil
-modafinil

One of them is sold as armodafinil

I believe one has a much short half life.

Anyway maybe you can specify

Adrafinil
Modafinil
Or
Armodafinil

 

[HezzaD]

I got a question about half lifes say if one has 12.1 hours so 24.2 hours, if taken before the 24hours, does more build up as I took anti d's for 2 weeks stopped for a week then realised it was helping me get out of bed e.t.c so now taking it properly.
easier question would be with olanzapine as that dont fully leave for sixty hours as the half life is 30, if you quit the drug would it take ages to get out system like subutex and methadone.

 

[Slow_Mobius]

It takes about 5 half lives to completely eliminate a drug

 

[d1nach]

All you need to do is make an excell spread sheet

For example say the drug half life is 24 hours (there are other things like cmax nut lets ignore that for now)

Say 100 mg (*technically its measuered in ng/ml-1 but its not relevent because we just want general idea of how much of a drug is in you as you continue to take it before leveling off)
0 hours 100mg total(t) 100mg
24 hours 50 mg 100mg t 150mg
48 hours 25 mg 50 mg 100 mg t 175
72 hours 12.5 mg 25mg 50 mg 100 mg t 187.5

As you can see the difference say to day becomes smaller and smallee till its basically levels off
+100 mg + 50 mg + 25 mg +12.5 mg ...


As for stopping assuming half life is equal at all levels on your body

Lazy so say its stable at 200
Day 1 off 100
2 50
3 25
4 12.5
5 6.2

It quickly becomes basically zeeo in a week given this example

 

[aspiringchemist]

It takes about 5 half lives to completely eliminate a drug

^^This

 

[d1nach]

Exactly I agree

 

[pally pete]

Do you mean adrafinil. I take modafinil the active metabolite of adrafinil

Modafinil has two isomers* might be wrong word

+modafinil
-modafinil

One of them is sold as armodafinil

I believe one has a much short half life.

Anyway maybe you can specify

Adrafinil
Modafinil
Or
Armodafinil

Me and a friend went through a short phase of experimenting with Modafinil and Armodafinil early last year. I was never that keen on either, (as I'm not a big fan of Stimulants) but my mate Loved them! As far as I'm aware you could/can still buy them legally online... I read somewhere that Modafinil/Armodafanil knock Benzodiazepines off the Benzodiazepine receptor sites??

I got a question about half lifes say if one has 12.1 hours so 24.2 hours, if taken before the 24hours, does more build up as I took anti d's for 2 weeks stopped for a week then realised it was helping me get out of bed e.t.c so now taking it properly.
easier question would be with olanzapine as that dont fully leave for sixty hours as the half life is 30, if you quit the drug would it take ages to get out system like subutex and methadone.

All you need to do is make an excell spread sheet

For example say the drug half life is 24 hours (there are other things like cmax nut lets ignore that for now)

Say 100 mg (*technically its measuered in ng/ml-1 but its not relevent because we just want general idea of how much of a drug is in you as you continue to take it before leveling off)
0 hours 100mg total(t) 100mg
24 hours 50 mg 100mg t 150mg
48 hours 25 mg 50 mg 100 mg t 175
72 hours 12.5 mg 25mg 50 mg 100 mg t 187.5

As you can see the difference say to day becomes smaller and smallee till its basically levels off
+100 mg + 50 mg + 25 mg +12.5 mg ...


As for stopping assuming half life is equal at all levels on your body

Lazy so say its stable at 200
Day 1 off 100
2 50
3 25
4 12.5
5 6.2

It quickly becomes basically zeeo in a week given this example

It takes about 5 half lives to completely eliminate a drug

^^This

Exactly I agree

I completely disagree.

I think this varies greatly from person to person. For example, I used to use Oxycodone quite regularly, which has a half life of around anywhere between 2 - 6 hours. Yet I would still show up as positive on drug tests over 7 days after no use?!

This makes no sense to me at all.

 

[HezzaD]

So with extended morphine 12hours would the halflife be 6hours? so 30hours in 5 days would this mean I withdraw after 15hours? im crap at this lol as im wanting to build my morphine in the week and just get wrecked on saturday as I took for 3 days extended and the day I took my morph the high was so much worth it like 50percent stronger I did rattle for the 3 days without the sickness as I was getting 5 mg instant a hour when used to 120mg instant in one go.

 

[d1nach]

Pally I think the reason the way we are talking about half life makes no sense to you and the way you use it makes no sense with our numbers is we are using different definitions.

I believe you are talking about the subjectives positive effects and or theraputic effects (IE when I take my oxycodone it generally lasts 3-7 hours until my back pain comes back.)

Or

The point it wont comeup on a drug test.


Here I am talking about half life as meaning from the concentration maximum value of a drug In the blood the time it takes to reach 1/2 that value.

And rather then the point it is undetectable by urine analysis a basic idea of how drugs with long half lifes might accumulate and be eliminated over days