Xanax Question for RCA7591

[Emmas Mom]

Not sure if it is okay to post a question for a specific person, but it was getting ignored on another post.  Please anyone who thinks they can answer this correctly please do!  This is related to another post about the elimination of xanax.


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!

[RCA7591]

I will help you to understand to the best of my ability.

When you consume a dose of Xanax, the drug is metabolized via Cytochrome P-450 (a liver enzyme), therefore, Xanax is metabolized by the liver. After the drug is metabolized by the liver, it is bound to plasma proteins, and peaks in your blood. This occurs very rapidly, and the onset of action is just as rapid. Drugs that bind to plasma proteins rapidly cross the blood-brain barrier. Xanax carries an eleven-hour half-life, so once the drug peaks in the plasma, it begins to decline very sharply (as you will see below). You can expect one dose of Xanax to last for roughly four hours (six hours maximum). After 4-6 hours, you'll be screaming for more!

The amount of drug present in your plasma is measured in nanograms/milliliters (ng/mL). Since everyone is individualized, a single dose of 0.25 mg will result in varying measurements. The range varies from 8-37 ng/mL. Rather than to use this unit of measure (which is extremely complicated), it is easier to express the plasma equivalent of the dosage in milligrams.

Assuming an eleven-hour half-life, Xanax follows the following curve in your case:

Initial dose = 0.25 mg

Time vs. Plasma Equivalent Dosage (remaining drug in your system):

1 Hour = 0.227 mg
2 Hours = 0.209 mg
3 hours = 0.193 mg
4 Hours = 0.180 mg
5 Hours = 0.168 mg
6 Hours = 0.158 mg
7 Hours = 0.149 mg
8 Hours = 0.142 mg
9 Hours = 0.134 mg
10 Hours = 0.128 mg
11 Hours = 0.125 mg (elimination half-life - 1/2 of a single dose is eliminated)
12 Hours = 0.114 mg

Your total daily dosage is 1.125 mg

7:00 AM - You take 0.25 mg, and have the plasma equivalent of 0.25 mg in your system.

11:00 AM - Four hours has elapsed since your first dose. You take a second dose of 0.25 mg. The plasma equivalent remaining from your first dose is 0.180 mg. Your total plasma equivalent at this point is 0.43 mg.

3:00 PM - Eight hours have elapsed since your first dose, and four hours have elapsed since your second dose. You take an additional dose of 0.25 mg. You now have the plasma equivalent of 0.142 mg from the first dose, 0.180 mg from the second dose, and 0.25 mg from the third dose. Your total equivalent plasma level is now 0.572 mg.

7:00 PM - Twelve hours have elapsed since your first dose, eight hours have elapsed since the second dose, and four hours have elapsed since your third dose. You again take 0.25 mg. You now have the plasma equivalent of 0.114 mg from the first dose, 0.142 mg from the second dose, 0.180 mg from the third dose, and 0.25 mg from the fourth dose. Your total plasma equivalent level is now 0.686 mg.

9:00 PM - Your final daily dose. Fourteen hours have elapsed since the first dose, ten hours have elapsed since the second dose, six hours have elapsed since the third dose, and two hours have elapsed since the fourth dose. You take 0.125 mg. You now have the plasma equivalent of 0.104 mg from the first dose, 0.128 mg from the second dose, 0.158 mg from the third dose, 0.209 mg from the fourth dose, and 0.125 mg from the fifth dose. Your total plasma equivalent is now 0.724 mg.

Plasma equivalent at bedtime = 0.724 mg.

You will now wait ten hours before taking your next morning dose at 7:00 AM. What happens during those ten hours to your plasma level? Take a look:

9:00 PM = 0.724 mg
10:00 PM = 0.604 mg
11:00 PM = 0.56 mg
12:00 AM = 0.520 mg
1:00 AM = 0.488 mg
2:00 AM = 0.458 mg
3:00 AM = 0.43 mg
4:00 AM = 0.411 mg
5:00 AM = 0.388 mg
6:00 AM = 0.371 mg
7:00AM = 0.371 mg

When you awake in the morning at 7:00 AM, you have 0.371 mg of Xanax remaining in your system. When you went to bed, you had 0.724 mg left in your system. This is 33% of your total daily dosage (0.371 mg). THIRTY-THREE PERCENT.

Xanax never accumulates (due to the short half-life). Thus, you probably wake up feeling miserable every morning. Not only that, but Xanax loses its effectiveness over the long-term. The chronic peaks and troughs in the blood plasma level not only give rise to "interdose anxiety", but to tolerance as well.

Speak with your doctor about implementing Klonopin (0.5 mg, three times daily). Unlike the plots posted above, Klonopin retains a steady blood-plasma level. This will prevent the "rollercoaster effect" that you are currently experiencing. In addition, Klonopin maintains its effectiveness forever.

To sum this up:

(1) You take 1.125 mg of Xanax daily
(2) At bedtime, 64% of this dosage remains in your system
(3) When you awake in the morning, 33% of this dosage remains in your system.

This is simply not adequate for the long-term treatment of an anxiety disorder.

Questions?

Ryan

[Emmas Mom]

Thank you so much for explaining this to me.  I was worried that it was completely out of my system by the time I took my morning dose.  It give me comfort to know that there is still some in my system, because of my irrational fear of seizures.  

I talked to my Dr about klonopin at my last appointment and he was hesitant because it has a long half life and he said it could be more addicting.  Although xanax does work for me, I think it is not working as well and I am getting rebound anxiety in between doses.  He also will not prescribe klonopin and xanax at the same time so I have a medication for breakthrough anxiety.  

He is a really good Dr and I think he will switch me to klonopin.  My hope was to be able to stop taking any benzo but I am not sure if that is going to happen right now.  One last question for you....if I switch toi klonopin do I just stop the xanax?

I apprecaite your help so much.