Looking for a Half Life Calculator

[HAL9000]

I had a half life excel spreadsheet formula that did hormone half lives but I'm interested in plugging in when (And how much) I take Valium and getting aguesstimation of the amount in me. Does anyone have or know where I can find one?

[vanderk]

I don't know of a specific spread sheet or calculator. But Valium has a rather long and variable half-life. Most sources say 20-80 hours. So full excretion could take 5-20 days. The active metabolite is the critical player here. It takes awhile to be released and quite awhile to be eliminated.

[Wooster]

Could you make a new halflife calculator using this kind of data?

http://www.vhpharmsci.com/vhformulary/tools/benzodiazepines-comparison.htm

[HAL9000]

Could you make a new halflife calculator using this kind of data?

http://www.vhpharmsc...-comparison.htm

I did one for hormone injections to try to get some kind of idea what going on. I'm not a big user of Excel so I'll have to do some extra work to figure this out. I really appreciate the link wooster. I've always thought that Valium kicks in fast (For me) and this seems to confirm that. Its peak effect gives me a couple of points in the start of a graph (or when you add to it later) which is where I think I'm heading. Maybe the important question is how long do you stay "medicated" and how much of this is when (If there is anytime) its detectable but not affecting the patient?

And for everyone reading this - I am always trying to understand everything about anything. How does it work. *Whats inside the Clock...

[notfred]

How fast a benzo takes effect has to do with how fat soluble it is, Valium is one of the most fat soluble benzos. The more fat soluble benzos make for a longer half life as some of the med is stored in the bodies fat cells. Being fat soluble means benzos pass the blood/brain barrier easier. Benzos that are more fat soluble pass easier and create higher concentration in the brain. I think Versed is the most fat soluble.

[AirMarshall]

The rule of thumb for half-lives is: Half life x 5 = time to steady state up/down

ex. Half life 18 hours x 5 = 90 hours 90/24hr = 3.75 days or 3 days 18 hours.

- Lithium half life 24hrs or 1 day x 5 = 5 days to steady state

-

Some people use a more conservative unit of "6"

You can see this graphically by using graph paper or draw a rough graph and take half of the remainder off each day. You will see that the amount remaining is gone on the fifth day. This principle applies whether you are increasing or decreasing a dosage or withdrawing totally.

[Cetkat]

The rule of thumb for half-lives is: Half life x 5 = time to steady state up/down

Can that be generalized to all meds? That's pretty useful.

[crtclms]

It is one of those generalizations that is generally true. I believe there are some exceptions, but after 5 half-lives, you are considered to no longer have a significant amount in your blood stream.

[colin]

It is one of those generalizations that is generally true. I believe there are some exceptions, but after 5 half-lives, you are considered to no longer have a significant amount in your blood stream.

Good stuff indeed. It should be pointed out that once a Benzo is out of your sytem that may not correlate with no longer suffering withdrawel. The brain can take considerable time to realign after long term benzo treatment-

[HAL9000]

This is probably a very lame question but I've asked a professional and I just don't get it.

I guess my question is this. If we use valium which has a half life of (Lets say) 100 hours.

I take the first 5 mg tab and I think it takes effect in 15 minutes and its max effect in one hour.

If I take a second tab 50 hours later (We are half way to the half life - 1/2 max dose in the bloodstream) Doesn't it add? In otherwords we will have a higher dose then the max dose of the first tab (Whatever that is)

I think what I've been told is Diazapam does its thing and is effective for a much shorter time then the half life etc. I was warned that using it has the baggage that its detectable for a long time after you've taken the last tab.

I'm taking this as needed but it doesn't seem to "add" or last 5 x 100 hours (Or even 100 hours) I'm a little worried that using it a couple times a week is going to keep adding up and I'll be really messed up on this stuff. I know I can ask my doctor to switch me to Xanax or Ativan. However the one time I took Ativan it put me into la la land. Valium (Diazapam) just solves the anxiety so I like that part. My doctor told me that I have to keep it to 2 or 3 times a week (Max) or I'm in serious danger of addiction problems. I guess Xanax or Ativan are no better?

I appreciate anyone spelling this out for me. And no, I'm not in a panic over this thing. Its more my curiousity how things work.

Thanks...

[AirMarshall]

Don't confuse Half Life with anything to do with 'effects', withdrawal, craving, onset of action, bioavailability, etc.

Half life is merely the measure of how long it takes for half of the active form of a medication to be converted, metabolized, excreted, or removed from the bloodstream/body.

Half life principle can be applied to system for which it is appropriate includind chemical and nuclear decay. Though, for some reason the nuclear folks use an extremely conservative form of 10 units when dealing with things like the fallout at Fukushima.

[Cetkat]

From my experience with the Xanax I take, when you're talking about cumulative effect, you're mainly dealing with taking a second while the first is still actively doing something. If I take one and it's not enough, I know (for me), I need to add another before it wears off in order to do any good. Otherwise it only seems to prolong the initial effect rather than build upon it.

When talking about addiction, I believe the concern comes from wanting to maintain the effect (and avoid the withdrawal) and doesn't have much to do with overall half-life and detectability. Physical dependence on the other hand, I'm not sure of. I'm guessing that would depend on the level of whatever metabolite that's behind it, but I'm uncertain if or how that would correlate with effect. That may also be dependent on the individual. I know it's easier for me to come off of things than what seems to be the norm around here.

I'm not sure how you would go about trying to calculate the latter if that's part of your goal.

[HAL9000]

From my experience with the Xanax I take, when you're talking about cumulative effect, you're mainly dealing with taking a second while the first is still actively doing something. If I take one and it's not enough, I know (for me), I need to add another before it wears off in order to do any good. Otherwise it only seems to prolong the initial effect rather than build upon it.

When talking about addiction, I believe the concern comes from wanting to maintain the effect (and avoid the withdrawal) and doesn't have much to do with overall half-life and detectability. Physical dependence on the other hand, I'm not sure of. I'm guessing that would depend on the level of whatever metabolite that's behind it, but I'm uncertain if or how that would correlate with effect. That may also be dependent on the individual. I know it's easier for me to come off of things than what seems to be the norm around here.

I'm not sure how you would go about trying to calculate the latter if that's part of your goal.

I appreciate your answers. I admit I'm often dense on some things until I piece things together and take them apart. With hormone injections I thought there was a cumulitive effect but I'm wondering if that really how that works. I see tdoc tomorrow and although she is not prescribing any drugs I think I'll ask her to spell this out (If she can)

With Diazapam I see the same thing as you do with Xanex. The first tab works or not and I have to take a second in a fairly short time period for it to work. Which seems to translate to diazapam working for a much smaller window then its half life.

Diazapam is really subtle (To me anyway) It seems to just quietly solves the physical anxiety and I've wondered if it really was doing anything. I've tried to be a tough guy (Not take any) and that made it clear is was having an effect. I'm curious if Xanax works that way for you?

I don't feel doped up or the "I don't care about anything" with Diazapam and I seem to be able to function at work, drive etc. Trying to figure this out is probably all a symptom of some diagnosed issue.

[Cetkat]

I appreciate your answers. I admit I'm often dense on some things until I piece things together and take them apart. With hormone injections I thought there was a cumulitive effect but I'm wondering if that really how that works. I see tdoc tomorrow and although she is not prescribing any drugs I think I'll ask her to spell this out (If she can)

With Diazapam I see the same thing as you do with Xanex. The first tab works or not and I have to take a second in a fairly short time period for it to work. Which seems to translate to diazapam working for a much smaller window then its half life.

Diazapam is really subtle (To me anyway) It seems to just quietly solves the physical anxiety and I've wondered if it really was doing anything. I've tried to be a tough guy (Not take any) and that made it clear is was having an effect. I'm curious if Xanax works that way for you?

I don't feel doped up or the "I don't care about anything" with Diazapam and I seem to be able to function at work, drive etc. Trying to figure this out is probably all a symptom of some diagnosed issue.

Well, hormones may be different. If what you take isn't metabolized but used directly by the body, then it seems to me that even a small level would still be actively doing something until it's completely used up & that amount could be built upon at any point. I don't know if it actually works that way in practice, but I don't think you can necessarily lump drugs and hormones together for that reason.

For me, the Xanax isn't as subtle. It doesn't make me feel "doped up" or anything, but I can feel it kick in and start dealing with the anxiety/panic. I mostly only use it for panic, so it's good that it has that ability. Something more subtle (like Klonopin, for instance) gets overpowered and isn't as effective. I tend to think that the ability for it to deal with anxiety is somewhat independent of taking so much that I feel out of it. If I get to that point, it was too much & doesn't seem to add much anti-anxiety wise. Actually, because feeling out of control will make me anxious - it's counter-productive.

[HAL9000]

I appreciate your answers. I admit I'm often dense on some things until I piece things together and take them apart. With hormone injections I thought there was a cumulitive effect but I'm wondering if that really how that works. I see tdoc tomorrow and although she is not prescribing any drugs I think I'll ask her to spell this out (If she can)

With Diazapam I see the same thing as you do with Xanex. The first tab works or not and I have to take a second in a fairly short time period for it to work. Which seems to translate to diazapam working for a much smaller window then its half life.

Diazapam is really subtle (To me anyway) It seems to just quietly solves the physical anxiety and I've wondered if it really was doing anything. I've tried to be a tough guy (Not take any) and that made it clear is was having an effect. I'm curious if Xanax works that way for you?

I don't feel doped up or the "I don't care about anything" with Diazapam and I seem to be able to function at work, drive etc. Trying to figure this out is probably all a symptom of some diagnosed issue.

Well, hormones may be different. If what you take isn't metabolized but used directly by the body, then it seems to me that even a small level would still be actively doing something until it's completely used up & that amount could be built upon at any point. I don't know if it actually works that way in practice, but I don't think you can necessarily lump drugs and hormones together for that reason.

For me, the Xanax isn't as subtle. It doesn't make me feel "doped up" or anything, but I can feel it kick in and start dealing with the anxiety/panic. I mostly only use it for panic, so it's good that it has that ability. Something more subtle (like Klonopin, for instance) gets overpowered and isn't as effective. I tend to think that the ability for it to deal with anxiety is somewhat independent of taking so much that I feel out of it. If I get to that point, it was too much & doesn't seem to add much anti-anxiety wise. Actually, because feeling out of control will make me anxious - it's counter-productive.

My doc suggested Xanax prn first and I declined because I had worked with a guy who used it (long term - daily) and I thought it "vegged" him out. At least from when I knew him pre-xanax. I now think that was pretty dumb. His reaction (If it even was from Xanax) doesn't mean its the same for everyone. Feeling out of control is probably what sets off anxiety for me. Relationship, finances, health issues whatever its all such un-fun.