Xanax and Klonopin: What Are the Adverse Effects?

Xanax and Klonopin Are Both Depressants


A question from a reader: I was in Iraq for more than two years, and I suffer from anxiety and panic attacks. I have been taking Xanax for about six months, and my physician just prescribed me Klonopin also. I am worried that if I take these drugs at the same time, I will experience adverse effects. Any help that you can provide would be very much appreciated.

Let's answer this question by first taking a closer look at what type of medications Xanax and Klonopin are and then looking at specific adverse effects.


Xanax (alprazolam) and Klonopin (clonazepam) belong to a class (or type) of medications known as benzodiazepines. Benzodiazepines are commonly used to treat anxiety and help many people who have a panic disorder.

Both of these medications have undesirable changes that may occur in some people, including the following:

  • Drug adverse effects may include daytime drowsiness, a hung-over feeling, mood changes, and allergic reactions;
  • These drugs can become less effective over time, and some people increase the dose to help relive anxiety. Such increases can lead to dependence and make it difficult to decrease the medication or stop it.

Because Xanax and Klonopin belong to the same drug class and are similar medications, they have similar adverse effects. Taking both of them at the same time may make it more likely that you will experience an adverse effect.

If you are not sure about the risk of adverse effects, you should check with the pharmacist at the drugstore where you get your medications.

Your pharmacist is an expert in drug information and can advise you about the risks.

You may also want to speak with your physician about how long you will be on Xanax and Klonopin and if it will be necessary for you to continue to take both medications. Xanax stays in your body for less time than Klonopin, and your physician may be starting the Klonopin to help you better control your anxiety and panic attacks.

If it helps, your physician may recommend that you decrease, and eventually stop, your Xanax.

Drug Interactions

You also need to be aware that both Xanax and Klonopin interact with many other medications. It is important that you tell your physician and your pharmacist about all medications that you are using, including over-the-counter drugs, and supplements such as vitamins and herbal remedies.

Both medications also interact with grapefruit juice, which may increase the amount of the medication that gets in your body. Exposure to grapefruit juice could increase your risk of adverse effects.

FYI: an article titled Grapefruit Juice: Is It Safe with Your Drug? provides information about grapefruit juice and drug interactions.

Post-Traumatic Stress Disorder (PTSD)

As you may know, many veterans returning from Iraq and Afghanistan suffer from PTSD and other problems related to their experience. Anxiety and panic attacks may be symptoms of PTSD in some people.

If you are concerned that you may have PTSD, please speak with your physician to make sure that you get properly diagnosed and receive access to appropriate services.

Listed below are some information resources about PTSD that you may find helpful.

Edited by Naveed Saleh, MD, MS, on 1/26/2016.

Selected Sources

Tsutaoka B. Chapter 31. Benzodiazepines. In: Olson KR. eds. Poisoning & Drug Overdose, 6e. New York, NY: McGraw-Hill; 2012. Accessed January 26, 2016.

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