Xanax dosage, forms, and strengths

Xanax is a prescription drug that is commonly used for the short-term management of symptoms of generalized anxiety disorder (GAD) and panic disorder. The active ingredient in Xanax, alprazolam, belongs to a class of drugs called benzodiazepines. It helps calm the brain by boosting the effects of a chemical called gamma-aminobutyric acid (GABA).

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Xanax forms and strengths

Xanax is available as an immediate-release tablet in four different strengths.

• Immediate-release tablets: 0.25 mg, 0.5 mg, 1 mg, and 2 mg

Xanax is also available as an extended-release tablet called Xanax XR. The available strengths are as follows:

• Extended-release tablets: 0.5 mg, 1 mg, 2 mg, and 3 mg

The active ingredient in Xanax may be found in other dosage forms, such as orally disintegrating tablets and oral solutions, for easier administration. However, they may have different brand names. 

Xanax dosage for adults

The Food and Drug Administration (FDA) has approved Xanax for the short-term treatment of generalized anxiety disorder and panic disorder in adults. Xanax is typically started at a lower dose three times daily. The starting dosage may then be gradually increased every three to four days by no more than 1 mg daily.

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Xanax dosage for generalized anxiety disorder (GAD)

Mental health professionals diagnose generalized anxiety disorder when a person experiences excessive worry about a range of problems almost daily for six months or more. 

• Starting dosage for generalized anxiety disorder: 0.25–0.5 mg taken orally three times per day

• Maximum dosage for generalized anxiety disorder: 4 mg per day

Xanax dosage for panic disorder

Xanax is approved to treat panic disorder with or without agoraphobia (fear of places that may cause panic or embarrassment) in adults. People with panic disorder may experience frequent and uncontrollable “panic attacks”—periods of intense and overwhelming fear—that come on suddenly and affect daily functioning. 

• Starting dosage for panic disorder: 0.5 mg taken orally three times per day

• Maximum dosage for panic disorder: Not specified

While no maximum dose for panic disorder has been defined, studies have shown that up to 10 mg per day have been used in some patients.

Xanax dosage restrictions

Some people may require a lower dosage of Xanax. The medication should be started at the lowest possible dose and increased slowly in older patients who may experience higher levels of the drug. 

Those starting treatment with ritonavir are recommended to take a lower dosage of Xanax due to an increased risk of Xanax levels and serious side effects. The dosage of Xanax may be gradually increased after 10 to 14 days of taking Xanax and ritonavir together.

In addition, alprazolam is processed by the liver. Therefore, people with liver (hepatic) problems generally start at a lower dosage to reduce the risk of Xanax side effects.

Xanax dosage for pets

Alprazolam and other benzodiazepines are often used in dogs and cats on an as-needed basis to treat symptoms of specific phobias, such as car rides or noises. Alprazolam is also sometimes given to cats with soiling or urine-marking behaviors. 

Dogs and cats are only rarely put on long-term alprazolam therapy. In most cases, the drug will be given before an anxiety-triggering event, like a thunderstorm, or when the animal is experiencing panic or anxiety. A veterinarian will determine each dose by the animal’s weight. Always talk to a veterinary professional before using medications to calm an animal. 

How to take Xanax

Xanax is taken as a tablet several times a day with or without food.

• Take the medicine as directed. The dose may need to be adjusted regularly until an effective dose is reached.

• A Xanax prescription will include a medication guide. Read and follow the patient instructions included in the medication guide.

• Store Xanax tablets at room temperature (68–77°F) in a secure container out of the reach of children.

• Swallow tablets whole with a glass of water. Do not crush, chew, or break the tablet.

Xanax dosage FAQs

Xanax vs. Xanax XR: What’s the difference in doses?

Xanax is FDA-approved to treat generalized anxiety disorder and panic disorder. The extended-release version, Xanax XR, however, is only FDA-approved to treat panic disorder. Xanax immediate-release tablets are started at dosages ranging from 0.25 mg to 0.5 mg three times daily, depending on the condition being treated. Xanax XR, however, is intended to be taken once daily—usually in the morning—in doses ranging from 0.5 to 6 mg.

How long does it take Xanax to work?

Xanax starts working within an hour of taking a dose. It reaches its peak concentration in the blood within about two hours. Xanax can be taken with or without food. Food does not typically affect the body’s ability to absorb and use the drug.

How long does Xanax stay in your system?

Xanax has an average half-life of about 11 hours, meaning it takes this long for half of the dose to be cleared from your body. Because it can take four to five half-lives for drugs to be completely cleared from the body, it may take around two to three days for Xanax to be completely eliminated. The exact duration may vary based on factors like age, metabolism, and dosage.

What happens if I miss a dose of Xanax?

Take the missed dose when remembered. However, if it is nearly time for the next scheduled dose, skip the missed dose and take the next dose as scheduled. Do not, under any circumstances, take extra medicine or a double dose to make up for a missed dose.

How long can you take Xanax?

Xanax is only intended to be taken for the short term. Alprazolam is a Schedule IV controlled substance, meaning it has the potential for drug abuse, dependence, and withdrawal. It is unknown if Xanax is safe and effective when used to treat anxiety disorder for more than four months and panic disorder for more than 10 weeks.

How do I stop taking Xanax?

Stopping Xanax should be done gradually and under the supervision of a doctor or healthcare provider. Abruptly stopping the medication may lead to withdrawal symptoms, such as anxiety, dizziness, fatigue, depression, and, in severe cases, psychosis, mania, or seizures. Your healthcare provider will likely create a tapering schedule to slowly reduce your dosage over time, minimizing the risk of withdrawal. Always consult a healthcare professional before making any changes to your medication regimen.

What is the maximum dosage for Xanax?

For general anxiety disorder, the maximum daily dose of Xanax should not exceed 4 mg. While there is no specified maximum Xanax dosage for panic disorder, patients have been prescribed doses as high as 10 mg per day.

Can you overdose on Xanax? 

Yes, it is possible to overdose on Xanax. Taking large doses of Xanax may lead to severe drowsiness, confusion, impaired coordination, and even life-threatening conditions like respiratory depression or coma. If you suspect an overdose, seek medical attention immediately. Always use Xanax as prescribed by your healthcare provider to avoid the risk of overdose.

What happens when you mix Xanax and alcohol?

Do not drink alcohol when taking Xanax. Both are central nervous system depressants. The combination will increase the sedative effects of both substances, including sleepiness, lightheadedness, memory impairment, loss of coordination, breathing problems, coma, and even death. For the same reason, the use of Xanax should be avoided or monitored while taking other CNS depressants like opioids, muscle relaxants, and first-generation antihistamines. 

Sources

• Xanax highlights of prescribing information, U.S. Food and Drug Administration (2023)

• Xanax XR highlights of prescribing information, U.S. Food and Drug Administration (2021)

• Anxiety disorders, National Institute of Mental Health (2024)

• Agoraphobia, National Institute of Mental Health (2024)

• Absence of food effect on the extent of alprazolam absorption from an orally disintegrating tablet, Pharmacotherapy (2007)

• Alprazolam, StatPearls (2023)

• A review of alprazolam use, misuse, and withdrawal, Journal of Addiction Medicine (2018)