xanax the 1/2 life??

[jimgreg]

when the 1/2 life of xanax says 11 hrs..so if i take my prescribed dose of 0.5mgs 4 aday  every 4 hrs..then at bedtime the 1/2 life would be 1mg??  would that mean thats still active in me...i do know what 1/2 life means,just not this part of it???????????????( please help me understand this??)   thanks.......

[RCA7591]

Assuming an eleven-hour half-life:

Starting dose = 0.5 mg

Hour #1 = 0.47 mg
Hour #2 = 0.41 mg
Hour #3 = 0.39 mg
Hour #4 = 0.36 mg
Hour #5 = 0.34 mg
Hour #6 = 0.31 mg
Hour #7 = 0.30 mg
Hour #8 = 0.28 mg
Hour #9 = 0.27 mg
Hour #10 = 0.25 mg
Hour #11 = 0.25 mg (1/2 of initial dose eliminated)
Hour #12 = 0.23 mg
Hour #13 = 0.23 mg
Hour #14 = 0.21 mg
Hour #15 = 0.21 mg
Hour #16 = 0.19 mg
Hour #17 = 0.19 mg
Hour # 18 = 0.18 mg

Now, you take 0.5 mg, q.i.d. (every six hours). The plasma level would follow this curve:

Dose #1 = plasma equivalent of 0.5 mg

Dose #2 = plasma equivalent of 0.31 mg from the first dose plus 0.5 mg from the second dose. Total = plasma equivalent of 0.81 mg.

Dose #3 = plasma equivalent of 0.23 mg from the first dose, 0.31 mg from the second dose, and 0.5 mg from the dose. Total = plasma equivalent of 1.04 mg.

Dose #4 = plasma equivalent of 0.18 mg from the first dose, 0.23 mg from the second dose, 0.31 mg from the third dose, and 0.5 mg from the fourth dose. Total = plasma equivalent of 1.22 mg.

You took 2 mg, and ended up with a plasma level 61% of that amount (1.22 mg). As you can see, Xanax does not accumulate, as it is rapidly eliminated from the body. You're pretty close with the 1 mg estimate.

Half-life aside (which is closer to six hours), the onset of action for Xanax is twenty minutes, and the duration of action is six hours. The drug exerts a clinical effect within a six-hour duration, after which point efficacy is lost fairly rapidly.

Xanax is not intended for long-term use, as the drug doesn't accumulate adequately to prevent interdose and tolerance to its effects. It's best reserved for as-needed use, given its fast onset of action and limited duration of action.

~Ryan

[pth2snake]

Hi There;

You seem super smart. Today is the first day I've been taking Xanax. I had taken it it for stress for three days 7 years ago. My life has been fairly stable the past years. I am currently taking Topamax 100mg for Bi-Polar 2   (Mood) disorder and ADHD and also started back on prozac 20 mg I have been off that fro 7 months. The Prozac I've never had trouble with but I tried to live with the cup half empty feeling all these months and I'm ready to feel better now. I tried to stay awy from the narcotics because I have ten years in Recovery (cocaine, alchohol) so I'm gonna be very carefull on this. I've ben ok on adderall over the years and havent abused it at all (but on day I doubled up and was honest to my doc right away.
My Question for ya is Im going on my old mix 300 Lithium, 100 topamax and 20 prozac- until these all kick in ill be taking these xanax to feel better prn and as of today i feel great I took my first two. But I dont want to abuse them so i was thinkingmaybe of just taking them if I get super exited other wise not taking them at all.

Does that sound smart?

I know my P doc knows what hes doing because i have been sober and balanced and this hypomania episode got me so drained and this Xanax reallys got me feeling realzed and at ease and i feel like i can get stuff done. What do you thnk?  Take very day ? Or only in emergncy when super nervous??Thanks andrea

[Emmas Mom]

Would you mind explaning to me when xanax is fully out of my system by the way I take my dosages?  I have posted before that my anxiety has caused muscle twitches which makes me think I am going to have a seizure, and I know xanax withdrawal can make you have a seizure and I know it is a short acting medication so it eliminates quickly from your body.  I am hoping that this could give me some peace of mind about the time between my last dose at night and first one in the morning.

7:00AM .25
11:00AM .25
3:00PM .25
7:00PM .25
9:00PM .125

I tried to understand what you out in the post above, but it was so confusing.  Can you show me with my doses the same type thing?  I appreciate your help!

[Suzyq0826]

I have been on Xanax for 5 years, and the way that you propose taking them is the way that I have and what is recommended for this particular medication...on an as-needed basis. When I feel an anxiety attack coming on (and I know pretty much in advance now) I take a Xanax and in less than 30 minutes I'm fine. On the days that I don't need them, I don't take them...although they are always with me....just in case.
I've never taken Xanax in combination with any other meds however, but if your doctor prescribed Xanax for you together with the other meds, you are probably going to be fine with taking them on an as-needed basis also.
Good luck,
Suzy

[Emmas Mom]

My dr has been taking it on a regular basis, even if I do not feel anxious to try and get my panic attacks under control right now.  I go back and see him on Monday for a follow up.  Is it bad I am taking it on a schedule?  He is a general practicioner, not a psychiatrist.  He is leary of long acting medications.