Clonazepam

Boxed warning: 

Using benzodiazepines and opioids together can cause sedation, difficulty breathing, coma, death, and clinically significant physical dependence. Avoid alcohol use while taking benzodiazepines. Alcohol and other recreational drugs may increase the risk of life-threatening side effects, misuse, and addiction.

The drug should be prescribed at the minimum doses needed to treat the condition and only when no appropriate alternative is available. Using clonazepam outside the direction of your doctor, in the context of a longer-term treatment, or at a higher daily dose significantly increases the risk of dependence, misuse, and withdrawal. 

Consult your doctor before abruptly discontinuing your medication or changing your dose, as this may lead to severe and life-threatening withdrawal symptoms. It's essential to reduce your dose gradually and under the supervision of a doctor to reduce the risk of withdrawal.

What is clonazepam?

Clonazepam is a benzodiazepine, which is a class of drugs that helps calm the brain and nervous system. Also called benzos or BZs, benzodiazepines work by changing how the signaling chemical gamma-aminobutyric acid (GABA) functions within the body.

Clonazepam is a long-acting benzodiazepine, which means it stays in the body longer than others, like alprazolam (Xanax) and lorazepam (Ativan). The leading brand of clonazepam in the US is Klonopin, but many other name brands are available in other countries. 

What is clonazepam used to treat?

Clonazepam is a prescription-only medication used mainly for seizure and panic disorders. It is approved by the US Food and Drug Administration (FDA) for treating the following:¹

What Is Panic Disorder: Everything You Need To Know

• Seizure disorders:

  • Childhood motor seizures:

    • Absence seizures (petit mal)

    • Lennox-Gastaut syndrome (a severe form of epilepsy)

    • Infantile spasms (a type of seizure occurring in babies)

  • Other seizure disorders:

    • Tonic-clonic seizures (grand mal)

    • Psychomotor seizures (complex partial seizures)

    • Myoclonic seizures (muscle jerks and twitches)

    • Focal motor seizures

  • Panic disorder and panic attacks, including agoraphobia

Clonazepam can be used alone or with other medications for combination therapy. Your doctor will determine the right medications and dosages for you based on your condition.

Clonazepam is sometimes prescribed off-label for the following conditions:²

• Acute mania, as a sedative or tranquilizer

• Restless legs syndrome

• Insomnia, REM sleep disorders, and sleep terrors in children two years and older

• Rapid eye movement behavior disorder

• Tourette syndrome³

• Alcohol withdrawal⁴

• Anxiety and related disorders

• Bruxism (grinding, gnashing, or clenching the teeth)

• Treatment-resistant depression

Dosage forms and strengths

Clonazepam is taken orally and is available in tablet and oral disintegrating tablet (ODT) forms.

Clonazepam tablets are available in the following strengths:⁵ ⁶

• Tablets: 0.5mg, 1mg, 2mg (generic, Klonopin)

• ODTs: 0.125mg, 0.25mg, 0.5mg, 1mg, and 2mg (generic only)

The dosage you take will depend on your age, your condition and its severity, your other medications and health conditions, and other factors.

Your dosage will depend on your age, condition and severity, other medications and health conditions, and other factors. Your doctor will likely prescribe a low dose and gradually increase it to determine the lowest adequate amount.

 Typical doses are as follows:⁷

• For panic disorder:

• Adults usually start with a dose of 0.25mg twice daily, with increases as needed up to a maximum amount of 4mg daily. Seniors may begin with a lower dose.

• Clonazepam hasn't been proven safe and effective for children under 18 years for the treatment of panic disorders.

• For seizure disorders:

• Adults typically start with a dose of 0.5mg three times daily with gradual increases up to a maximum daily dose of 20mg. Seniors often start with a lower dose.

• In children, the dose varies based on age and weight.

Always follow your doctor's instructions precisely when taking clonazepam, even if your prescribed dose doesn’t fall within the usual range. In some cases, clonazepam may be taken as needed to control seizures and panic attacks.

How do you take clonazepam?

Some people take clonazepam once daily, usually before bed. Others take two or three daily doses. Follow your doctor’s instructions closely. If anything is unclear, as your doctor or pharmacist for clarification.⁸

All forms of clonazepam can be taken with or without water or food. However, if you experience stomach upset after taking the medication, it might be best to take it with food.

It's important to take clonazepam at around the same time each day. Set an alarm or cell phone alert to remind you, or have a close friend or family member check in to ensure you're taking your medication as directed.

If you take the ODT form of clonazepam, keep the tablets in the foil packaging until you’re ready to take them. Once you remove a tablet from the packaging, take it right away. Place the tablet on your tongue and let it dissolve. You can drink water once the tablet has dissolved completely.⁹

Seeing results

It may take a few days to weeks to experience the maximum benefits when taking clonazepam; however, the drug starts working quickly, reaching the maximum blood concentration within four hours. It is also long-acting and can remain active in your body for up to 40 hours.¹⁰

You will feel effects such as calmness, sleepiness, reduced panic, and reduced anxiety soon after you take clonazepam, but those taking it for seizure disorders may not see significant improvements in seizures and involuntary muscle spasms for a few weeks.

Who should not take clonazepam?

Clonazepam is not suitable for everyone. It is contraindicated in people who have:¹¹

• Significant liver disease

• Had a previous allergic reaction to clonazepam or other benzodiazepines

• Acute narrow angle glaucoma

Doctors typically don’t prescribe the drug for people with obstructive sleep apnea, as there’s evidence the drug may increase the risk of acute respiratory failure (a serious condition in which the lungs can’t get enough oxygen into the blood) in people with the condition.¹²

Clonazepam may be prescribed cautiously for patients who:¹³

• Have myasthenia gravis, a rare condition causing muscle weakness

• Have a diagnosed personality disorder

• Experience suicidal thoughts or tendencies or have recently lost a loved one

• Are currently using alcohol or any illicit substances or have an alcohol or substance use disorder

• Are planning a surgical or dental procedure in the near future

• Have cerebellar or spinal ataxia (loss of voluntary muscle control and coordination)

• Are pregnant, trying to get pregnant, or breastfeeding

While some patients with the above-mentioned conditions can take clonazepam safely, alternative medications are often better suited.

People aged 65 and older may need a blood test to assess liver function before starting clonazepam. They may also be more sensitive to the action of benzodiazepines and must stay vigilant in monitoring for adverse effects.

Potential side effects of clonazepam

Taking clonazepam can cause mild or severe side effects. While each person's reaction to the medication is unique, commonly-reported side effects include the following:¹⁴

• Problems with coordination and balance

• Dizziness

• Tiredness or fatigue

• Sleepiness 

• Depression

• Heart palpitations

• Memory problems or confusion

Common side effects usually resolve within a few days. If you experience persistent side effects, even mild ones, speak with your doctor.

Less common side effects include the following:

• Confusion

• Low libido

• Urinary retention

• Insomnia and other sleep disturbances

• Muscle weakness or pain

• Lack of motivation

• Blurred vision

• Short-term memory loss or anterograde amnesia (inability to form new memories)

• Restlessness

• Depression

Some patients have also reported changes in personality or behavior, poor muscle control and clumsiness, and general discomfort, but these are uncommon.

Rare adverse effects from clonazepam include the following:

• Agitation, aggression, hostility, or impulsive behavior

• Suicidal tendencies

• Incontinence (inability to control urination or bowel movements)

• Psychosis (being disconnected from reality, including delusions and realistic hallucinations)

It’s essential to monitor for sudden changes in personality, mood, thoughts, or behavior while taking clonazepam. These changes, as well as suicidal thoughts or attempts, are serious side effects and require urgent medical attention.

Overdose

Like other benzodiazepines, clonazepam has a significant potential for misuse. For this reason, there’s a high risk of overdose in people taking the drug.

Symptoms of an overdose may include any of the following:¹⁵

• Extreme sleepiness

• Very slow breathing

• Blurred or double vision

• Difficulty thinking and extreme confusion

• Slurred speech

• Loss of muscle control

• Loss of consciousness, coma

Severe overdoses can result in start-and-stop breathing, a heart attack, a very low heart rate, and coma.

A clonazepam overdose can occur with blood levels above 0.08mcg/mL and happen quickly if the patient has taken other sedatives such as alcohol, opioids (including heroin, fentanyl, morphine), or barbiturates (such as some sleeping pills).¹⁶

If you suspect you or someone in your care has taken too much clonazepam, call 911 immediately. Take the bottle of pills with you to the hospital to aid the healthcare team in providing appropriate treatment.

Allergy information

Severe allergic reactions to clonazepam are rare. However, some people may be allergic to the inactive ingredients used to produce the drug.

If you notice symptoms of an allergic reaction, such as a swollen face or tongue, skin rashes or hives, vomiting, severe dizziness, and trouble breathing, seek immediate medical attention.

Long-term use of clonazepam

Clonazepam and other benzodiazepines are usually prescribed for short-term treatment due to the risk of addiction and dependence, which may occur even when the drug is used in low doses and as directed.

Additionally, the body tends to develop resistance to the effects of the drug (tolerance) over time, requiring patients to take higher doses to achieve the same results. When a person builds tolerance to a drug, the risk of developing dependence is elevated. Stopping the medication at that point could cause severe withdrawal symptoms, which is why clonazepam is usually not prescribed for longer than a month.

The high risk of addiction and dependency led the US Drug Enforcement Administration (DEA) to classify clonazepam as a Schedule IV controlled substance.¹⁷ ¹⁸

Pregnancy category

The US FDA designated clonazepam as a pregnancy category D drug. There is evidence clonazepam may harm the fetus and increase the risks of premature birth, low birth weight, and congenital anomalies.¹⁹ ²⁰

Clonazepam and pregnancy

Clonazepam should only be used during pregnancy if the benefit to the patient justifies the risk of fetal adverse effects. It’s worth noting that newborns exposed to the drug while in utero, particularly in late pregnancy, may experience withdrawal symptoms.

Clonazepam and breastfeeding

Clonazepam passes through breast milk and can cause adverse effects in a breastfeeding infant. Your doctor will work with you to minimize the risks and determine the best course of therapy for your condition.

Missed doses

It is vital that patients taking clonazepam maintain the dosage schedule directed by their prescriber. If you miss a dose, take it as soon as you remember. However, if it's nearly time for your next dose, skip the missed one and take the next dose at the regular time. Do not double your dose to make up for a missed one.

Drug interactions

Clonazepam may interact with a variety of other medications, recreational drugs, and alcoholic beverages. These interactions can make clonazepam less effective, increase the action of the other drug, or cause adverse reactions. Some medications and other substances known to interact with clonazepam include:²¹ ²² ²³

• Ketoconazole (Nizoral) and itraconazole (Sporanox), used to treat fungal infections

• Nefazodone (Serzone) and fluvoxamine (Luvox), used to treat depression 

• Cimetidine (Tagamet), used to treat ulcers, heartburn, and indigestion

• Ritonavir (Norvir), a medication for treating HIV-AIDS

• Idelalisib (Zydelig), a cancer medication²⁴

• Carbamazepine (Tegretol) and phenytoin (Dilantin), used to treat seizures

• Phenobarbital (Luminal), used to control convulsions and seizures

• Other benzodiazepines, such as diazepam (Valium), alprazolam (Xanax), clorazepate (Tranxene), and chlordiazepoxide (Librium) 

• Ivacaftor (Kalydeco), used for treating cystic fibrosis

• Sodium oxybate (GHB), an illicit drug

• Opiates, such as morphine, oxycodone, codeine, hydrocodone, and heroin²⁵

• Valerian, an herb often used in traditional and complementary medicine

This list of possible interactions is not exhaustive. Give your doctor a complete list of any medications, supplements, and drugs you take (regularly or occasionally) so they can ensure clonazepam is safe for you.

Can I drink alcohol while taking clonazepam?

It is strongly recommended not to use alcohol while you're taking clonazepam. Alcohol and street drugs that slow the functions of the brain and nervous system increase the risk of life-threatening side effects.

When taken together, alcohol and clonazepam have cumulative sedative effects that could trigger severe breathing problems, low blood pressure, coma, or even death.²⁶

What to discuss with your doctor before starting clonazepam

Because clonazepam is a potent medication with potentially severe side effects and risks, you should be honest with your doctor about your lifestyle and history of drug and alcohol use. Here are some of the topics to discuss with your doctor before taking clonazepam:²⁷

• Any previous medications you have taken for your condition (especially benzodiazepines) and whether they caused any reactions or side effects

• Any other health issues you have, including medication allergies

• All other medications you currently or occasionally take, including over-the-counter products and herbal and nutritional supplements

• Your alcohol and recreational drug use

• If you have been thinking about harming or hurting yourself or have a history of psychiatric issues

• Upcoming medical or dental procedures

• Your career, lifestyle, and hobbies — some side effects of clonazepam may make certain activities, such as driving and operating machinery, less safe

• Other non-medicinal treatments you're receiving, including behavioral therapy, talk therapy, and treatment for alcohol or substance use

• If you're pregnant, planning to get pregnant, or breastfeeding

Stopping clonazepam

Clonazepam has a high risk of addiction and physical dependency. If you stop taking it suddenly, especially after taking high doses for a long time, you may develop withdrawal symptoms that could be life-threatening. These include irritability, insomnia, anxiety, depression, headaches, blurry vision, vomiting, diarrhea, muscle pain, confusion, hallucinations, sweating, rapid heart rate, and seizures.²⁸

Stopping clonazepam can also worsen the medical condition it’s treating, leading to a recurrence of seizures or anxiety symptoms. Do not change your dosage or stop taking the drug without guidance from a healthcare professional.

Drug approval history

• 1960: Clonazepam was patented²⁹

• 1975: The FDA approved clonazepam³⁰

Tips for taking clonazepam³¹

• You can take clonazepam with or without food.

• Try to take your medication around the same time each day.

• Speak with your doctor about eating grapefruit (or drinking grapefruit juice) while taking clonazepam.

• Store your medication at room temperature. Don’t store it in areas prone to moisture, like the bathroom.

Frequently asked questions

Does clonazepam affect mood?

Yes, clonazepam can cause changes in your behavior and mood. The drug calms the brain and nervous system, reducing irritation, mood swings, irritability, and anxiety. However, it can also increase suicidal thoughts and tendencies, which is why doctors screen for psychiatric disorders before prescribing clonazepam.

What will happen if I take clonazepam daily?

Clonazepam is usually not prescribed for long periods. However, those taking the drug will usually take it daily for the (short) prescribed period.

Is clonazepam a sleeping pill?

No, clonazepam is not a sleeping pill, but it’s known to cause drowsiness. Doctors may prescribe the drug off-label to treat insomnia and sleeping problems, but it is not FDA-approved for these uses.