Clonazepam: 7 things you should know
Medically reviewed by Carmen Fookes, BPharm. Last updated on Nov 5, 2020.
1. How it works
- Clonazepam acts on nerve cells to calm abnormal electrical activity within the brain.
- Clonazepam calms and sedates and may be used for the treatment of anxiety, as an anticonvulsant, or for its sedative effects.
- Experts aren't exactly sure how clonazepam works, but believe its effects are due to its ability to strongly bind to the GABA-benzodiazepine receptor complex, which enhances the affinity for GABA (a neurotransmitter that blocks impulses between nerve cells in the brain). Low levels of GABA have been linked to anxiety, mood disorders, seizure disorders, and pain.
- Clonazepam belongs to the class of medicines known as benzodiazepines.
- May be used for the short-term treatment of panic disorder and certain forms of anxiety.
- May also be used to treat certain seizure disorders (for example, Lennox Gastaut).
- May also be used off-label, that is, prescribed for conditions that are not FDA-approved but may be well established.
- Generic clonazepam is available.
If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:
- Drowsiness, sleepiness, or dizziness are the most common side effects reported. Any one of these side effects may impair reaction skills and affect a person's ability to drive or operate machinery or increase the risk of falls. Alcohol may potentiate these effects and should be avoided.
- Body aches and pains, palpitations, memory disturbance, headache, tiredness, and several other side effects have also been reported.
- May rarely cause respiratory depression (unusually slow and shallow breathing). The risk is greater with larger dosages of clonazepam, in people with pre-existing respiratory conditions, or if clonazepam is used in addition to other medications that also cause respiratory depression (such as opioids).
- Clonazepam is potentially addictive and may cause both emotional and physical dependence. The lowest dose should be used for the shortest possible time. Clonazepam supplies may be sought out by drug seekers.
- Withdrawal symptoms (including convulsions, tremors, cramps, vomiting, sweating, or insomnia) may occur with abrupt discontinuation; taper off slowly under a doctor's supervision.
- As with other anticonvulsants, clonazepam may increase the risk of suicidal thoughts or behavior which may be noticeable as early as one week following initiation.
- Women should not breastfeed their baby while receiving clonazepam.
- Clonazepam may increase the risk of depression or unmask depression or increase the risk of suicidal thoughts. Monitor for worsening of mood.
- Occasionally, paradoxical reactions (the opposite of what is to be expected) may occur. Symptoms include anxiety, agitation, rage, sleep disturbances, sexual disinhibition, or hallucinations.
- May interact with several other medications including opioids, other medications that cause sedation (such as alcohol, antipsychotics, antidepressants, or sedative antihistamines), clozapine, probenecid, and valproate.
- May not be suitable for some people including those with pre-existing respiratory disease (such as COPD or sleep apnea), acute narrow-angle glaucoma, a history of drug or alcohol abuse, at high risk of falls, women who are pregnant or breastfeeding, or people with kidney or liver disease. The elderly or frail may be especially sensitive to clonazepam's effects.
Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects
- Take exactly as directed by your doctor. Do not increase or decrease the dosage without his or her advice. If you have been taking clonazepam for a long time do not stop suddenly as withdrawal reactions (blurred vision, insomnia, sweating, rarely seizures) may occur. Your doctor will advise you on how to taper off the dose. Keep out of sight of potential drug seekers.
- Swallow regular-release tablets whole with water.
- For orally disintegrating tablets, open the pouch and peel back the foil on the blister; do not push the tablet through the foil. Use dry hands to remove the tablet and place it in the mouth; it will dissolve rapidly in saliva.
- Clonazepam may cause sleepiness and affect your ability to drive or perform other complex tasks. Avoid doing these activities if clonazepam has this effect on you.
- Avoid drinking alcohol while taking clonazepam because it may enhance the side effects of sedation and respiratory depression.
- Clonazepam may make you feel dizzy, increasing your risk of falls. Be careful when sitting or standing up after lying down.
- If you think you have become dependant on clonazepam or addicted to it, talk with your doctor.
- Do not take any other medications with clonazepam including those bought over the counter without first checking with your pharmacist or doctor that they are compatible.
- If your mood changes or you experience depression or a worsening of depression, talk with your doctor.
- Do not use clonazepam if you are allergic to it or other benzodiazepines like alprazolam, lorazepam, or oxazepam.
- Do not start or discontinue clonazepam during pregnancy without speaking to your provider first.
6. Response and Effectiveness
- Clonazepam takes approximately 20-60 minutes to start working. The peak effects of clonazepam are reached in 1-4 hours.
Medicines that interact with clonazepam may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with clonazepam. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.
Common medications that may interact with clonazepam include:
- anti-anxiety medications, including other benzodiazepines, such as diazepam and oxazepam
- anticonvulsants such as phenytoin
- antidepressants, such as amitriptyline, imipramine, nortriptyline
- antihistamines that cause sedation, such as diphenhydramine
- monoamine oxidase inhibitors, such as selegiline, isocarboxazid, or phenelzine
- opioid analgesics such as oxycodone and morphine
- muscle relaxants such as cyclobenzaprine
- sleeping pills, such as zolpidem
- some chemotherapy treatments
- some medications used to treat mental illness, such as clozapine and thioridazine.
Alcohol may worsen the side effects of clonazepam such as drowsiness and dizziness.
Note that this list is not all-inclusive and includes only common medications that may interact with clonazepam. You should refer to the prescribing information for clonazepam for a complete list of interactions.
Clonazepam. Revised 04/2020. Drugs.com https://www.drugs.com/ppa/clonazepam.html
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use clonazepam only for the indication prescribed.
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