Klonopin (clonazepam) is in a class of anxiolytic (antianxiety and antipanic) medications called benzodiazepines. It works by decreasing abnormal electrical activity in the brain. Doctors prescribe this drug to treat seizures and panic attacks. Off-label use (meaning not indicated on the U.S. Food and Drug Administration-approved packaging) includes restless legs syndrome, sleepwalking, and social phobia in adults.

Klonopin has been prescribed for a number of neurological conditions, such as epilepsy and anxiety, since the 1950s and 1960s. Klonopin was originally brought to market in 1975 to treat epileptic seizures.

Dosage FAQs

  • What is a safe dose of this drug?
    • Panic and anxiety: An initial adult dose of Klonopin is 0.25 mg two times a day. The dose can be increased to 1 mg per day every three days. The maximum dose of this drug should not exceed 4 mg per day. In such cases, the dose of Klonopin may be increased by 0.125 mg to 0.25 mg two times a day every three days until panic is controlled.
    • Seizures: Klonopin is useful alone or as an adjunct in the treatment of Lennox-Gastaut, akinetic, and myoclonic seizures. An initial adult dose should not exceed 1.5 mg per day in three divided doses. Dosage may be increased by 0.5 mg to 1 mg every three days until the conditions improve. A maintenance dosage of this drug must be given according to individual need and depending upon response. Maximum daily dose should not exceed 20 mg.
    • Posttraumatic stress: Doses of Klonopin for PTSD typically range from 0.25 mg to 3 mg per day.
    • Social phobia in adults: For social phobia, a dose ranging from 1 mg to 2.5 mg is usually administered.
       
  • What are other off-label uses for this drug?
    Off-label use refers to any time a doctor uses this drug for treatment not specified by the FDA packaging. This is a regular practice and for this drug includes:
    • Burning mouth syndrome
    • Essential tremors
    • Tourette syndrome
    • Major depression
    • Multiple sclerosis
    • Periodic limb movement disorder
    • Restless legs syndrome
    • Tinnitus
    • Vertigo
    • West syndrome (infantile spasms)
       
  • How is this drug processed by my body?
    Klonopin is well-absorbed after oral administration and reaches a maximum plasma concentration after one to four hours. It has a bioavailability of about 90%. 85% of this drug is bound to plasma protein. The elimination half-life of Klonopin is typically 30 to 40 hours. Less than 2% of unchanged Klonopin is excreted in urine. Metabolites are also excreted in the urine.
     

  • Find a Therapist

    Advanced Search
    Is this drug safe to use while pregnant?
    The FDA has placed this medication in pregnancy category D, which means there is evidence of risk to human fetuses during pregnancy. However, many conditions for which this medication is prescribed also pose a risk to pregnant mothers and their babies. A thorough assessment should be performed by you and your doctor to determine if the risks outweigh the benefits if you are prescribed this drug.
     
  • How can I get the most out of my treatment with this drug?
    Panic and anxiety, two conditions treated with this drug, are also treated with success by various types of psychotherapy. If you are experiencing anxiety or panic, consider finding a therapist or counselor to help you develop healthy coping strategies, learn more about what you are experiencing, and develop a self-care routine to mitigate symptoms in the future.

Drug Interactions of Klonopin   

Like many anxiolytic medications, this drug has several important interactions of which to be aware, including:

  • Cimetidine: Cimetidine inhibits liver enzymes. This causes a decrease in metabolism and increases the effects of this medication.
  • Clozapine: Clozapine may cause an increased risk of toxicity when taking with this medication.
  • Fluconazole, Ketoconazole, Indinavir, Nelfinavir and Itraconazole: These drugs may increase the effects of Klonopin by decreasing its metabolism.
  • Omeprazole: Omeprazole inhibits the cyp450 enzyme system and causes an increase in the effects of this drug.
  • Ritonavir, Saquinavir, and Voriconazole: Protease inhibitors reduce the metabolism of this medication and may increase its effects.
  • Telithromycin: Telithromycin may reduce metabolism of Klonopin and increase the occurrence and severity of side effects.
  • Triprolidine: This drug and Klonopin both depress the central nervous system.
  • Vigabatrin: This drug increases the plasma concentration of Klonopin by 30% and decreases the time to reach maximum concentration by about 45%.
  • Oral contraceptives: Oral contraceptives decrease the metabolism of Klonopin causing an increase in its adverse and therapeutic effects.
  • Monoamine Oxidase Inhibitors (MAOIs): This category of drugs can lower blood pressure and increase sedation. When taken with Klonopin, the respiratory system is also depressed.
  • Sedatives or sleeping pills: These medications may cause severe sedation and may be fatal when taken with this medication.
  • Carbamazepine, Phenytoin and Theophylline: All of these drugs can decrease the effectiveness of this medication.
  • Tricyclic antidepressants (TCAs): Klonopin may cause increased sedation when administered with tricyclic antidepressants.    
  • Alcohol and caffeine: Alcohol and excessive caffeine intake should be avoided when taking this medication.

Possible Side Effects

Klonopin's side effects may be different depending on the condition it is being used to treat. It may cause the following reactions:

  • Drowsiness
  • Ataxia (shaky movements and unsteady gait)
  • Memory problems
  • Allergic reaction or inflamed sinuses or nasal passages
  • Fatigue
  • Menstrual problems for women
  • Sleep issues including insomnia
  • Speech problems
  • Tremors
  • Abnormal eye movements
  • Constipation, nausea, or Diarrhea
  • Thrombocytopenia (fewer platelets in the blood which can cause spontaneous bruising and excessive bleeding)
  • Respiratory depression
  • Difficulty urinating
  • Psychological and/or physical dependence

Withdrawing from Klonopin

You should not stop taking this medication abruptly. In order to reduce the withdrawal symptoms you should gradually taper down the dose based on a safe plan formulated with your doctor. Possible symptoms of withdrawal include:

  • Hallucinations
  • Seizures
  • Behavioral changes
  • Sweating
  • Tremors or uncontrollable shaking
  • Anxiety
  • Insomnia

Chemistry of Klonopin

Klonopin is a derivative of nitrazepam and has a molecular mass of 315.715. It has an additional chlorine added to the structure of nitrazepam and is therefore a chloro-nitrobenzodiazepine. It has a light yellow color, a crystalline structure, and a faint odor. Klonopin is insoluble in water, slightly soluble in alcohol, sparingly soluble in acetone and chloroform, and slightly soluble in ether.

References:

  1. Rudolph U, Mohler H: GABA-based therapeutic approaches: GABA A receptor subtype functions. Current Opinion in Pharmacology 2006;6:18.
  2. Sanger DJ. The pharmacology and mechanism of action of new generation, nonbenzodiazepine hypnotic agents. CNS Drugs 2004;18(Suppl 1):9.
  3. Chouinard G: Issues in the clinical use of benzodiazepines: Potency, withdrawal, and rebound. Journal of Clinical Psychiatry 2004;65(Suppl 5):7.
  4. Clayton T et al: An updated unified pharmacophore model of the benzodiazepine binding site on gamma-aminobutyric acid(a) receptors: Correlation with comparative models. Current Medicinal Chemistry 2007;14:2755.
  5. Cloos JM, Ferreira V: Current use of benzodiazepines in anxiety disorders. Current Opinion in Psychiatry 2009;22:90.

Page content reviewed by James Pendleton, ND.