For patients receiving doses greater than 4 mg per day, periodic reassessment and consideration of dosage reduction is advised. In a controlled postmarketing dose-response study, patients treated with doses of XANAX greater than 4 mg per day for 3 months were able to taper to 50% of their total maintenance dose without apparent loss of clinical benefit.

The necessary duration of treatment for PD in patients responding to XANAX is unknown. After a period of extended freedom from panic attacks, a carefully supervised tapered discontinuation may be attempted, but there is evidence that this may often be difficult to accomplish without recurrence of symptoms and/or the manifestation of withdrawal phenomena.

How long does Xanax last for / stay in your system?

Xanax (alprazolam) is a medication used to treat anxiety and panic disorders. One dose of Xanax can last anywhere from 31 hours to 134.5 hours (5.6 days) in the body, depending on factors related to the individual who took it. However, the calming, relaxing, and sedative effects of Xanax usually wear off within about eight to twelve hours.buy Xanax Bromazolam 4mgXanax is taken by mouth and quickly absorbed into the bloodstream. Effects should be noticed within an hour and the medicine reaches peak concentrations in the body after one to two hours. People who take Xanax regularly can build up a tolerance to it and effects, such as a feeling of calm or sedation, may take longer to develop or not be felt as strongly as before.

Xanax is usually prescribed three times a day because its effects in the body (calming, sedation, relaxing) tend to wear off within eight hours for most people. However, one dose of Xanax remains detectable in the body for two to five days –

What factors determine the half-life of Xanax?

Factors that determine how long a dose of Xanax will persist in the body for include:

• A person’s age: Xanax lasts for longer in elderly people. The average half-life in the elderly is 16.3 hours, compared to 11.2 hours in younger, healthy adults
• Weight: Xanax lasts for longer in heavier people, because obesity makes it harder for your body to break down Xanax. The average half-life in people who are overweight/obese is 21.8 hours, compared to 11.2 hours in young, healthy adults
• Ethnicity: Xanax lasts for longer in Asian people. The average half-life in Asian people is 14 hours, compared to 11.2 hours in Caucasians
• Metabolism: People who exercise a lot or who have a faster metabolism clear Xanax faster than those who don’t exercise or do any physical activity. The half-life of Xanax is shorter in these people
• Liver function: Xanax lasts for longer in people with poor liver function. The average half-life in people with alcoholic liver disease is 19.7 hours, compared to 11.2 hours in young, healthy adults
• Length of  taking of Xanax;  If you take Xanax regularly, then you will have a higher concentration in your bloodstream and it will take longer to fully eliminate it all. But because you have built up a tolerance to the drug, you may not necessarily feel its effects for longer
• Interacting medications: Xanax lasts longer when it is taken with drugs that inhibit CYP3A4 (eg, erythromycin, ketoconazole, nefazodone, oral contraceptives), one of its metabolizing pathways. Other drugs (such as carbamazepine, St John’s wort), may decrease the half-life of Xanax
• Smoking: The half-life of Xanax may be reduced by up to 50% in smokers compared to nonsmokers. This means that smokers metabolize Xanax more quickly than nonsmokers
• Alcohol: Alcohol can increase the effects and half-life of Xanax, and can lead to dangerous side effects which could be fatal.