How Long Does Xanax Last?

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How long does Xanax last depends on several key factors. Xanax is a benzodiazepine prescribed for treating severe anxiety and panic disorders. It works by increasing the ability of a neurotransmitter called gamma-aminobutyric acid (GABA) to suppress functioning of the central nervous system.


How long the anxiolytic effects of Xanax tablets last various by how much a person takes and whether they have built a tolerance to the drug.  It varies among individuals depending on;

  • age
  • health
  • weight

Tolerance to benzodiazepines like Xanax builds quickly, usually after two or three weeks of taking Xanax. As tolerance builds to Xanax, it will eventually take longer for you to feel its effects. Although Xanax is not prescribed for treating insomnia, some new users may fall asleep for a short time after taking a dose of Xanax. Since Xanax is not formulated to impact the sleep centers of the brain, it will not help you stay asleep all night but can relieve anxiety at bedtime so you can fall asleep.

Xanax tablets are available in four different dosages:

  • 0.25 mg
  • 0.5 mg
  • 1mg
  • 2mg


The length of time someone takes Xanax has a direct affect on how long it takes for the body to reach peak plasma level and metabolize the drug.

People taking Xanax daily for several months will maintain higher concentrations of Xanax in their blood. However, they may not feel the effects of Xanax longer because of building tolerance to the drug.

  • Smaller doses of Xanax provide calming effects for several hours but this depends heavily on factors affecting a person’s ability to metabolize Xanax.


Those with severe panic disorders may need to be prescribed 10mg daily to prevent debilitating panic attacks from interfering with their ability to lead a normal life.

  • For some people, 2mg of Xanax per day alleviates their anxiety for up to eight hours.


Standard starting doses for relieving anxiety and panic are between 0.25 and 0.5mg, three to four times a day. Doctors may increase doses of Xanax gradually to a maximum 4mg per day.

  • If you are taking 4mg of Xanax daily, effects are likely to last 10 to 12 hours.

How Long Does It Take Before Someone Feels the Effects of Xanax?

Xanax, like other benzodiazepines, is metabolized by the liver.

  • In people with normal liver functioning, Xanax’s sedative effects should be felt within 30 to 60 minutes of ingestion.

How Much is Too Much Xanax Per Day?

Anytime you take more Xanax than what your doctor prescribes will put you at risk for overdose. Signs of a possible Xanax overdose include:

  • Confusion
  • Inability to walk properly
  • Slurred speech
  • Sudden drop in blood pressure (hypotension)
  • Slowed breathing/respiratory depression
  • Unresponsiveness/coma-like condition
  • Hallucinations

Mixing Xanax with other drugs or alcohol increases the chance of overdose and could worsen signs of an overdose. According to the National Institute of Drug Abuse, overdose deaths due to misuse of benzodiazepines increased from approximately 2000 to 9000 deaths. In addition to combining Xanax and alcohol, Xanax abusers who end up in emergency rooms because of life-threatening symptoms have been known to mix Xanax with heroin, cocaine, fentanyl and methamphetamine.

How Long Does It Take for Xanax to Expire?

The U.S. FDA states that expired prescriptions may be less effective or pose a risk to your health if you take them. The chemical composition in oral and liquid medications can change over time, provide reduced strength and even develop bacterial growth if medicines are kept in warm, humid conditions.

  • The expiration date of Xanax and most other prescription drugs is one year from the date filled.

Although Xanax may still exert its sedative effects after one year, users are strongly recommended to discard expired Xanax properly to avoid suffering possible adverse side effects.