How Long Does Xanax Last?

Medically reviewed by Alan Carter, PharmD on November 20, 2017Written by Jacquelyn Cafasso on November 20, 2017

Alprazolam, more commonly known by its brand name, Xanax, is a medication indicated to treat anxiety and panic disorders. Xanax is in a class of medications known as benzodiazepines. It’s considered a mild tranquilizer.

Xanax helps to calm the nerves and induces a feeling of relaxation. In high doses, however, it has the potential to be abused and can lead to dependence (addiction). For this reason, it’s classified as a federal controlled substance (C-IV).

If you’re new to taking Xanax, you may be wondering how long the effects will last in your body, factors that might influence how long Xanax stays in your system, and what to do if you decide to stop taking it.

How long does it take to feel the effects of Xanax?

Xanax is taken by mouth and is readily absorbed into the bloodstream. You should start feeling the effects of Xanax in under an hour. The medication reaches peak concentrations in the bloodstream in one to two hours following ingestion.

People who take Xanax will often build up a tolerance. For these people, it may take longer to feel the sedative effects of Xanax or the sedation may not feel as strong.

How long does it take for the effects of Xanax to wear off?

One way to find out how long a drug will last in the body is to measure its half-life. The half-life is the time it takes for half of the drug to be eliminated from the body.

Xanax has an average half-life of roughly 11 hours in healthy adults. In other words, it takes 11 hours for the average healthy person to eliminate half of the dose of Xanax. However, it’s important to note that everyone metabolizes medications differently, so the half-life will vary from person to person. Studies have shown that the half-life of Xanax ranges from 6.3 to 26.9 hours, depending on the person.

It takes several half-lives to fully eliminate a drug. For most people, Xanax will fully clear their body within two to four days. But you will stop “feeling” the sedative effects of Xanax before the drug has actually fully cleared your body. This is why you may be prescribed Xanax up to three times per day.

Factors that influence how long the effects of Xanax last

A number of factors can influence the time it takes for Xanax to clear the body. These include:

  • age
  • weight
  • race
  • metabolism
  • liver function
  • how long you’ve been taking Xanax
  • dosage
  • other medications

There’s no difference in the average half-life between men and women.

Age

The half-life of Xanax is higher in elderly people. Studies have found that the average half-life is 16.3 hours in healthy elderly people, compared to an average half-life of roughly 11 hours in younger, healthy adults.

Weight

For obese individuals, it may be more difficult for your body to break down Xanax. The half-life of Xanax in people who are obese is higher than average. It ranged between 9.9 and 40.4 hours, with an average of 21.8 hours.

Ethnicity

Studies have found that the half-life of Xanax is increased by 25 percent in Asians compared to Caucasians.

Metabolism

A higher basal metabolic rate may decrease the time it takes for Xanax to leave the body. People who exercise regularly or have faster metabolisms may be able to excrete Xanax faster than people who are sedentary.

Liver function

It takes longer for people with alcoholic liver disease to break down, or metabolize, Xanax. On average, the half-life of Xanax in people with this liver problem is 19.7 hours.

Dosage

Each tablet of Xanax contains 0.25, 0.5, 1, or 2 milligrams (mg) of alprazolam. In general, higher doses will take longer for your body to fully metabolize.

The total length of time you’ve been taking Xanax will also affect how long the effects last in your body. People who have been taking Xanax on a regular basis will consistently maintain a higher concentration in their bloodstream. It will take longer to fully eliminate all of the Xanax from your body, though you may not necessarily “feel” the sedative effects for longer because you’ve built up a tolerance to the medication.

Other medications

Xanax is cleared by your body through a pathway known as cytochrome P450 3A (CYP3A). Drugs that inhibit CYP3A4 make it more difficult for your body to break down Xanax. This means that the effects of Xanax will last longer.

Medications that increase the time it takes for Xanax to leave the body include:

On the other hand, certain medications help to induce, or speed up the process, of CYP3A. These medications will make your body break down Xanax even faster. An example is the seizure medication carbamazepine (Tegretol) and an herbal remedy known as St. John’s wort.

Alcohol use

Alcohol and Xanax taken in combination have a synergistic effect on one another. This means that the effects of Xanax are increased if you consume alcohol. It will take longer to clear Xanax from your body. Combining alcohol with Xanax can lead to dangerous side effects, including the possibility of a fatal overdose.

Withdrawal symptoms

You shouldn’t stop taking Xanax abruptly without consulting your doctor because you can have serious withdrawal symptoms. These may include:

  • mild dysphoria (feeling uneasy and restless)
  • an inability to sleep
  • muscle cramps
  • vomiting
  • sweating
  • tremors
  • convulsions
  • hallucinations

Instead, the dosage should be reduced gradually over time to prevent withdrawal. This is called tapering. It’s suggested that the daily dosage is decreased by no more than 0.5 mg every three days.

For panic disorders, the dosage of Xanax is often greater than 4 mg per day. This can lead to severe physical and emotional dependence and make it much more difficult to taper treatment. Your doctor will help you discontinue Xanax in a careful and safe way.

Takeaway

Xanax should fully clear the body in less than four days for most healthy individuals. However, there are a number of factors that could alter the time it takes for Xanax to clear the body, including age, race, weight, and dose.

If you’ve been prescribed Xanax, make sure your doctor knows what other medications and supplements you’re taking. Only take your prescribed dose of Xanax, even if you think the medication isn’t working anymore. High doses can cause dangerous side effects. It’s also possible to overdose on Xanax, especially if it’s taken with alcohol or in conjunction with opioid pain medications.

Although they’re prescription drugs, benzodiazepines such as Xanax have been associated with serious health issues, especially when it’s taken long term. It’s important to only stop taking Xanax under your doctor’s supervision. The withdrawal process can be dangerous without medical help.

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