9 Clonazepam Side Effects You Should Know About

Clonazepam (Klonopin) is FDA approved to treat certain seizure disorders and panic disorder. It’s also sometimes used off-label for anxiety and restless leg syndrome. But it’s not a first-choice medication for these conditions.

Clonazepam is part of the benzodiazepine medication class (sometimes referred to as “benzos”). If you have a prescription for clonazepam, you’ll want to know about the potential risks of taking it. Below, we cover nine clonazepam side effects and how you might manage them.

1. Drowsiness

In clinical trials, up to 50% of people taking clonazepam experienced drowsiness. This is because clonazepam works by slowing down brain activity. It attaches to receptors (chemical binding sites) in the brain called gamma-aminobutyric acid (GABA) receptors. Binding to GABA receptors has a calming effect on the brain. But this can also cause sedative effects, or drowsiness. 

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Many other medications also have sedative effects. These include:

• Other benzos, like alprazolam (Xanax)

• Sleep medications, like zolpidem (Ambien, Ambien CR)

• Barbiturates, like phenobarbital

• Opioids, like hydrocodone/acetaminophen and morphine (MS Contin)

Alcohol can also slow down the brain. So it’s a good idea to avoid combining clonazepam with alcohol or any of the medications discussed above.

For people taking clonazepam throughout the day, drowsiness may be a problem during the daytime. When you start clonazepam, avoid activities that require you to be alert. This is especially true for driving or operating other machinery.

If clonazepam makes you too drowsy, talk to your healthcare provider. Depending on why you’re taking it, they may recommend a different dose or another medication.

2. Coordination problems

In clinical trials, coordination problems (ataxia) occurred in up to 30% of people taking clonazepam for seizures. It’s less common in people taking it for panic disorder. But it’s still reported to occur in about 2% of people taking the typical daily dose for panic disorder (1 mg per day).

Symptoms of poor coordination include trouble walking normally. And with poor coordination, the risk of falls increases, especially in older adults. This can be dangerous.

While taking clonazepam, keep an eye out for signs that you’re having trouble moving as well as you normally do. Talk to your healthcare provider if you notice something out of the ordinary. They can help determine the cause and whether to adjust your clonazepam dose.

3. Dizziness

Dizziness is another possible clonazepam side effect. It can happen in about 5% of people taking clonazepam at usual doses for panic disorder. The risk is greater at higher doses, which are more common in seizure disorder.

Similar to drowsiness, feeling dizzy can make it more dangerous to do certain activities. You should be careful moving around if you feel dizzy. You may need to sit or lay down for the dizziness to pass. This may mean you need to avoid driving or performing other activities that require alertness.

After you’ve taken clonazepam for a few days, you’ll have a better idea of how the medication affects you. Let your healthcare provider know if your dizziness is severe or if it continues long term.

4. Upper respiratory tract infections

Upper respiratory tract infections (URTIs) may be more likely while taking clonazepam. This includes infections like the common cold and sinus infections.

It may seem odd that clonazepam can increase the risk of infections. The reason isn’t fully clear, but this may occur because of benzos’ effect on GABA receptors. Binding to these receptors may decrease the body’s immune response.

URTI symptoms may include facial pain or pressure, runny nose, or a sore throat. Coughing is also a common symptom. If you’re experiencing these symptoms, talk to your healthcare provider. They may suggest over the counter medications to treat your symptoms. If your infection is caused by bacteria, taking an antibiotic may be necessary. But many URTIs are caused by viruses and get better on their own. 

5. Depression

Depression is another possible side effect of clonazepam. Other mood-related problems, like nervousness and mood swings, can also occur. These side effects are more likely to happen in people with existing mental health conditions.

If you have new or worsening depression while taking clonazepam, let your healthcare provider know. They may adjust your dosage or suggest changing to another medication.

6. Suicidal thoughts or behaviors

All seizure medications, including clonazepam, can cause suicidal thoughts or behaviors. This is a rare side effect. But it can happen to anyone.

If you have any new or worsening symptoms of depression, or unusual changes in your behavior or mood, contact your healthcare provider immediately. And if you or someone you know is having thoughts of suicide, you’re not alone, and help is available. Call the National Suicide Prevention Lifeline at 988, or text HOME to 741-741 to reach the Crisis Text Line.

7. Memory problems

Short-term memory loss is a possible side effect of benzos. But the risk of having long-term memory loss (like dementia) is less likely.

If you have memory problems or changes in thinking while taking clonazepam, let your healthcare provider know. You may need to switch to an alternative medication.

8. Misuse

Like all benzos, clonazepam is a controlled substance. Controlled substances can cause mental and physical dependence, which can lead to misuse. In fact, the FDA warned that benzos may cause dependence, misuse, and overdose in September 2020. They gave all benzos a boxed warning for this reason. This is the most serious warning the FDA can assign a medication.

Dependence and misuse can happen even if benzos are taken exactly as prescribed. But it’s more likely if you use them differently than how they were prescribed to you. This includes taking higher doses or taking doses more often than recommended. That’s why it’s important to follow your healthcare provider’s instructions on how to take clonazepam. And only take it if it’s really needed.

If you or someone you know struggles with substance use, help is available. Call SAMHSA’s National Helpline at 1-800-662-4357 to learn about resources in your area.

Keep in mind: Abruptly stopping clonazepam can cause withdrawal symptoms. This is more likely if you’ve been taking clonazepam on a regular basis. Symptoms include anxiety, tremors, or sweating. More seriously, withdrawal can lead to seizures or hallucinations. So always check with your healthcare provider before stopping clonazepam. They can help you lower your dose safely.

9. Overdose

Benzo overdose can occur with clonazepam. High doses, or combining clonazepam with other medications that slow down the brain, can make overdose more likely. To lower the risk of overdose with clonazepam, avoid other medications or substances that can also slow down breathing. Examples include alcohol and opioids. And take the lowest effective dose for the shortest amount of time possible.

Symptoms of clonazepam overdose may include severe drowsiness, slowed breathing, and confusion. This is a medical emergency that requires immediate medical care. If you think you or someone you know has taken too much clonazepam, call 911 and get medical help right away.

When should you contact your healthcare provider about clonazepam side effects?

It’s a good idea to talk to your provider or pharmacist about clonazepam side effects before you begin taking it. This will help you be aware of any risks before you start the medication.

If you’re taking clonazepam and having mild side effects like drowsiness, you may be able to manage them at home. Still, let your provider know if you have any side effects after starting clonazepam. They can help you decide if it makes sense to continue the medication.

If you’re having serious side effects, like suicidal thoughts or overdose, you should seek emergency care.

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Written by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

Edited by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

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