Klonopin vs. Xanax: differences and similarities

Anxiety can sometimes make day-to-day tasks seem overwhelming. If you’ve constantly been feeling on edge, and it’s interfering with your sleep, relationships, and work, then it may be time to consider talking to a healthcare professional. They may suggest short-term treatment with a prescription medication such as Klonopin or Xanax to ease your anxiety symptoms.

Read on to learn more about the similarities and differences between these two medications.

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Klonopin (generic name: clonazepam) and Xanax (generic name: alprazolam) are anxiolytic (anti-anxiety) medications. They both belong to a class of drugs called benzodiazepines, also known as “benzos.”

Benzodiazepines boost the activity of gamma-aminobutyric acid (GABA), a neurotransmitter. This neurotransmitter blocks certain brain signals to slow down the activity of your central nervous system (CNS) and produce a calming effect (Bounds, 2020). 

Other treatments—like antidepressants and therapy—are generally preferred over benzos for managing anxiety disorders long-term because antidepressants and therapy carry fewer risks. Benzodiazepines are controlled substances, and taking them can lead to addiction, withdrawal, and drug abuse (DEA, n.d.).

To minimize the risks of benzodiazepines, healthcare providers may prescribe Klonopin or Xanax as a short-term anxiety treatment. Or, they may instruct you to take a dose only as needed to stop a sudden seizure or ease a panic attack. It's important not to change your dose without talking to your healthcare provider. If you've been taking one of these medications for a while, suddenly reducing your dose or stopping treatment can cause withdrawal symptoms (Roche, 2021; Pfizer, 2021).

Here’s a quick summary of information about Klonopin (Roche, 2021):

• Generic name: clonazepam

• Drug class: benzodiazepine

• Controlled substance? Yes, schedule IV (DEA, n.d.)

• Year approved by the Food and Drug Administration (FDA): 1975

Clonazepam (Klonopin) is a drug that you take by mouth. Clonazepam (Klonopin) tablets come in three strengths: 0.5 milligrams (mg), 1 mg, and 2 mg. The drug is also available in an ODT (orally disintegrating tablet), which is a tablet that dissolves in your mouth. Clonazepam ODT is available in five strengths: 0.125 mg, 0.25 mg, 0.5 mg, 1 mg, and 2 mg (Roche, 2021; Alembic, 2018).

Clonazepam typically starts working within 30 minutes after taking a dose, reaching its maximum effects within one to four hours. Its effects usually last six to 12 hours or longer (Basit, 2021; Roche, 2021).

You should take this medication according to your healthcare provider’s instructions.

What is Klonopin used to treat?

Clonazepam is FDA-approved to treat (Roche, 2021):

• Panic disorder in adults.

• Seizure disorders, also called epilepsy, in adults and children.

Clonazepam (Klonopin) can also be used “off-label” to treat other conditions. Clonzaepam’s off-label uses include (Basit, 2021):

• Insomnia: a sleep disorder in which a person has trouble falling asleep or staying asleep.

• REM sleep behavior disorder: a sleep disorder that causes people to physically act out their dreams while asleep.

• Mania: a psychological condition that causes a person to experience changes in their mood and behavior, such as hyperactivity and intense euphoria (feeling “high”). Mania is often a symptom of bipolar disorder.

• Tardive dyskinesia: random uncontrolled movements that can occur as a side effect of taking certain antipsychotic medications.

• Restless leg syndrome: a nervous system disorder that causes a constant uncontrollable urge to move the legs, interrupting a person’s sleep.

Here’s a quick summary about Xanax (Pfizer, 2021):

• Generic name: alprazolam

• Drug class: benzodiazepine

• Controlled substance? Yes, schedule IV (DEA, n.d.)

• Year approved by the FDA: 1981

Like clonazepam, alprazolam is an oral medication. It’s most commonly prescribed in oral tablet form (Xanax), available in four strengths: 0.25 mg, 0.5 mg, 1 mg, and 2 mg. Alprazolam also comes in an extended-release tablet, an orally dissolving tablet, and a liquid solution (UpToDate, n.d.). 

Xanax starts working within 30 minutes after you take a dose. It reaches its maximum effects within one to two hours. Its effects usually last around six hours (George, 2020).

Alprazolam’s effects on the body do not last as long as the effects of clonazepam.

What is Xanax used to treat?

Xanax (alprazolam) is FDA-approved to treat the following conditions in adults (Pfizer, 2021):

• Generalized anxiety disorder (GAD)

• Panic disorder with or without agoraphobia

Alprazolam is also prescribed off-label to treat (Bounds, 2020):

• Short-term sleep problems like insomnia

• Severe delirium or agitation symptoms

Klonopin and Xanax can cause some similar side effects, as listed below. Because of these side effects, you should not drive or do other potentially dangerous tasks after taking clonazepam or alprazolam. Also, alcohol should be avoided because it can enhance the drowsiness side effect of these medications. 

The following lists include the most common side effects reported in separate clinical trials when each drug was compared to a placebo (Roche, 2021; Pfizer, 2021).

Side effects of Klonopin (clonazepam)

The most common side effects of clonazepam include (Roche, 2021):

• Sleepiness

• Dizziness

• Fatigue

• Problems with memory

• Trouble with coordination

Rarely, clonazepam (Klonopin) can cause serious side effects. People taking this medication may experience changes in mood or behavior, such as new or worsening depression and suicidal thoughts or actions.

Side effects of Xanax (alprazolam)

The most common side effects of alprazolam include (Pfizer, 2021; Ait-Daoud, 2018):

• Problems with coordination or unsteadiness

• Drowsiness

• Trouble speaking words clearly

• Lowered blood pressure

• Increased libido or sex drive

• Memory problems

• Dizziness

• Depression

Since Klonopin and Xanax belong to the same class of drugs, they carry similar interaction risks. This section includes just a few examples of important interactions that are possible.

The FDA has issued boxed warnings for potentially harmful interactions that can happen with benzodiazepine drugs, including clonazepam and alprazolam. Boxed warnings are the strongest type of warning from the FDA. 

While taking Klonopin or Xanax, you should not take medications or substances known as CNS depressants or “downers.” This is because these drugs or substances slow down the central nervous system, increasing the risk of side effects like excessive sedation, low blood pressure, or life-threatening overdose (FDA, 2020; Basit, 2021). Some examples of CNS depressants include:

• Alcohol

• Opioids like codeine, hydrocodone, tramadol, and heroin

• Other benzodiazepines like lorazepam (Ativan)

• “Sleeping pill” medications like zolpidem (Ambien)

Other drug interactions are possible with these medications. Klonopin and Xanax can potentially affect how your body metabolizes or breaks down other medications, including some used to treat anxiety or seizure disorders. So, it’s always a good idea to check with your pharmacist or healthcare provider before taking any other prescription drugs, over-the-counter medications, or herbal supplements with Klonopin or Xanax. 

We’ve given you a lot of information regarding the differences and similarities between these two medications. Here is a summary:

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How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

September 07, 2021

Written by

Patricia Weiser, PharmD

Fact checked by

Felix Gussone, MD

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About the medical reviewer

Felix Gussone, MD, Ro

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.