Xanax (Alprazolam) Vs. Klonopin (Clonazepam): What Is The Difference?

In our latest question and answer, the pharmacist discusses the difference between Xanax (alprazolam) and Klonopin (clonazepam).


I ran out of my alprazolam 1mg. Can I take a 0.5mg clonazepam instead?

Asked by Nora On Jul 25, 2018

Answered by
Medical Content Reviewed By PharmacistAnswers Staff

On Jul 25, 2018

Both Xanax (alprazolam) and Klonopin (clonazepam) are classified as benzodiazepines, but have several characteristics that differentiate them from one another. In fact, within the benzodiazepine class as a whole, individual drugs are differentiated primarily by their pharmacokinetic profiles, which result in large differences in:

  • Onset of action
  • Duration of action
  • Presence of active or non-active metabolites
  • Metabolic pathways (e.g. metabolized via CYP liver enzymes or without CYP enzyme involvement)

Below, we discuss the key differences between Xanax (alprazolam) and Klonopin (clonazepam).

Xanax Information

Xanax (alprazolam) is considered a rapid acting benzodiazepine, with a short duration of action. Other key characteristics include:

  • It is metabolized by CYP liver enzymes and therefore has many potential drug interactions.
  • Metabolism produces active metabolites, although they are thought to be only minimally active.

Due to its rapid onset of action, Xanax may act faster when it comes to treating symptoms (e.g. symptoms of anxiety) but it has been associated with high rates of rebound anxiety and withdrawal symptoms. In addition, it has a higher risk of abuse. In fact, alprazolam is one of the most abused benzodiazepines.

While benzodiazepines in generally aren't often recommended for insomnia, the fast onset and short duration of action of Xanax may be better suited for treating certain sleep disorders on an intermittent basis.

Klonopin Information

Klonopin (clonazepam) is considered a rapid to intermediate acting benzodiazepine, with an intermediate to long duration of action. Like Xanax, Klonopin:

  • Is metabolized by CYP liver enzymes (increased likelihood of drug interactions)
  • Produces active metabolites (although most sources state they are clinically insignificant)

Due to the longer duration of action of Klonopin, it may be better suited in certain patients, including those treating persistant anxiety disorders and for the treatment of epilepsy. In addition, if a patient has been taking a rapid acting, short duration benzodiazepine (e.g. Xanax), Klonopin is often used to aid these individuals in tapering off their medication as it has a long duration of action and can reduce the likelihood of withdrawal symptoms.

Comparing Xanax To Klonopin: Summary

Onset Of Action

Xanax: Rapid (Onset of action 15-30 minutes after administration with peak concentrations reached within 1-2 hours)

Klonopin: Rapid to intermediate (Onset of action around 30 minutes after administration with peak concentrations reached within 1-4 hours)

Duration Of Action

Xanax: Short (generally dosed two to four times daily)

Klonopin: Intermediate to long (generally dosed twice daily)

Active Metabolites?

Xanax: Yes (minimally active)

Klonopin: Yes (thought to be insignificant)


Xanax: CYP3A4 (more likely to have drug interactions)

Klonopin: CYP3A4 (more likely to have drug interactions)


Xanax and Klonopin are both used for a wide range of indications but:

  • Klonopin may be preferred for panic disorders and preventing seizures due to it's longer duration of action. Xanax generally should not be used long term.
  • In regard to extended use, the risk of withdrawal and rebound symptoms with Klonopin are lower than with Xanax.

Can You Switch Between Xanax And Klonopin?

You can certainly switch between Klonopin and Xanax based on what you and your doctor think will best treat your symptoms. However, if you have only been prescribed one, you should not switch, or use someone else's medication, without speaking with your doctor.

Taking Klonopin instead of Xanax without first checking with your doctor could cause your symptoms to not be appropriately treated. There are other factors to consider as well, such as drug interactions with concomitant medications and your risk of withdrawal, based on how long you have been taking Xanax.

About the Pharmacist

Dr. Brian Staiger Pharm.D

Dr. Brian Staiger is a licensed pharmacist in New York State and the founder of PharmacistAnswers.com. He graduated from the University At Buffalo with a Doctor of Pharmacy degree in 2010. He has been featured in numerous publications including the Huffington Post as well as a variety of health and pharmacy-related blogs. Please feel free to reach out to him directly if you have any inquiries or want to connect! He's answered thousands of medication and pharmacy-related questions and he's ready to answer yours! Brian.Staiger@PharmacistAnswers.com Office: 716-389-3076

About Xanax (Alprazolam)

Xanax (alprazolam) is a rapid acting oral benzodiazepine used for the treatment of anxiety and panic disorders. It is also used off-label for the short-term treatment of insomnia. Xanax has a short half-life but has relatively high potential for abuse due to its quick acting effects. Discontinuation can sometimes be difficult as there is a high risk of withdrawal symptoms in-between doses and may need to be tapered over weeks to months. The onset of action of Xanax is around 15 to 30 minutes after taking by mouth, with peak concentrations occurring within 1—2 hours. Xanax is also available as an extended release dosage form, Xanax XR.

About Klonopin (Clonazepam)

Klonnopin (clonazepam) is an oral benzodiazepine used primarily in the management of seizures but is also used for the treatment of anxiety and short-term insomnia. Klonopin is considered a rapid acting benzodiazepine with an intermediate duration of action. After taking by mouth, the onset of effect is generally 15-30 minutes, with the duration of action being between 6 and 12 hours. Clonazepam metabolism does not create active metabolites and it is not thought to accumulate in the body. Klonopin may be taken without regard to food but should be taken with a full glass of water.

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