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RJC-PharmD, Pharmacist
Category: Pharmacy
Satisfied Customers: 75
Experience:  Doctor of Pharmacy. UT Faculty. Immunizer, Compounder, MTM.
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if i take half of my 0.25 xanax does it still last for 6 hours

Resolved Question:

if i take half of my 0.25 xanax does it still last for 6 hours or is it only half of that since its half the dose?
Submitted: 4 years ago.
Category: Pharmacy
Expert:  RJC-PharmD replied 4 years ago.
Yes, it just won't have as much of an effect due to the lower dose. Regardless of dose, onset of action is between 15-30 minutes with peak effect around 1-2 hours after ingestion. It has an average half life somewhere around 11-12 hours, so the effect can last anywhere from 6-12 hours. A higher or lower dose will change strength of the effect, but not really the duration of action. I hope this helps.
Customer: replied 4 years ago.
so change of effect means a higher dose will make me feel better longer
Expert:  RJC-PharmD replied 4 years ago.
It's possible yes, but higher dose just means the effect will be stronger over the 6 hours that it lasts. It won't make the drug act longer, just stronger when it peaks 1-2 hours after taking it. If you are just looking for a longer lasting effect, and the problem isn't that it isn't working to treat your symptoms enough even 1-2 hours after taking it, then you would have to repeat the dose sooner or get an extended release version of the medicine, which is available. You might want to speak to your physician about the extended-release product.
Customer: replied 4 years ago.

is half of a 0.25 dose a common dose , or is it not much of theraputic dose

Expert:  RJC-PharmD replied 4 years ago.

Honestly, no it's not a common dose. Of course it depends on the person, but depending on circumstances and reasons for use anything less than 0.25mg is probably not very therapeutic in my opinion.

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Customer: replied 4 years ago.
i was also given lexapro, 10 mgs but have been hesitaint to start it. Is it a new drug, and is it safe without a lot of side effects. which drug changes the brain more, xanax or lexapro? which is stronger and more dangerous
Customer: replied 4 years ago.
is ativan different that xanax, and is it not as addictive and better for you
Expert:  RJC-PharmD replied 4 years ago.

Xanax is what's called a benzodiazepine. It works pretty much just to treat stress, anxiety, panic disorders, sleep disorders, etc. You can think of it kind of as a sedative to calm you down. It's meant to be used only on an "as needed" basis, as it is short acting and doesn't really work to change much in your brain function. Lexapro on the other hand is an antidepressant in the category of SSRIs. Main function is to treat depression, but it also treats generalized anxiety disorder. SSRIs must be taken daily for awhile to be effective, but they do indeed work. Their mechanism of action is more unknown, but daily use is thought to cause a whole cascade of functional changes in receptors and pathways in the brain mainly related to serotonin. This is why they take awhile to work. Anti-anxiety effects usually after the first 2 weeks, and antidepressive effects around 4-6 weeks. Taken daily, they do well to prevent generalized anxiety, but do not treat acute attacks. Treatment of acute anxiety is better managed with a benzodiazepine, such as Xanax.


In regards XXXXX XXXXX second question, Ativan is also a benzodiazepine like Xanax. All benzodiazepines work the same exact way. Their main difference is their onset of action (how quickly they work) and their durations of action (how long they last). As I stated previously, Xanax peaks at 1-2 hours, and can last anywhere from 6-12 hours. Ativan 2-4 hours, but can last anywhere from 10-20 hours.

Customer: replied 4 years ago.

what does it mean when you say it peaks, does that mean its on its way from working and has already been the strongest it could be. what is better for sleep, xanax or ativan.


Also if i take half of a 0.25 xanax every 10 hours or so does that mean it is accumulating in my body and i am getting a higher dose because i have taken it more often. as you can hear, iam afraid of getting addicted to it

Customer: replied 4 years ago.
when you say they last from 6 to 20 hours does that mean they are still working in my body and i can feel the effects for 20 hours. or does the peak time mean that i will not feel the effects much after it peaks
Expert:  RJC-PharmD replied 4 years ago.



Above is a simple, generic picture representation of how much drug is in your bloodstream relative to time, courtesy of Going up or down on the graph is the drug concentration in your blood. Moving from left to right is time since you took the drug. When the concentration of the drug is in the area between the dotted lines, it is therapeutic and will be having an effect on you. The "T-max" is the time at with the drug reaches it's highest concentration, or "peak" as I described before. The duration of action is how long the blood concentration is in the therapeutic range and is still affecting you. If you compared Xanax to Ativan, Xanax would reach the peak much more to the left, and the curve would come down faster out of the therapeutic range since it's duration of action is less. Ativan would curve up much slower to reach the peak, and then the curve coming back down would be more flat and less steep since it's duration of action is longer. I know this was a long answer, but I really want to make sure you understand. :)


Because Ativan lasts longer, it is usually recommended for insomnia over Xanax. In fact, Ativan is approved by the FDA for sleep, whereas Xanax is not. That doesn't mean it can't be used for sleep, just that it's not recommended the first drug to try.


Don't be afraid of getting addicted to it. It's usually the people who are afraid of addiction and are cognizant of it, that are not prone to experience it.


I've spent quite a bit of time answering this for you, and if I've answered your questions to your liking, I would appreciate clicking accept. Thanks :)


Referenced graph:

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