Last reviewed by Miljan Krcobic on August 28th, 2018.
What is Klonopin? What is Klonopin used for?
Klonopin is a Brand name for anxiolytic medicine that contains benzodiazepine drug clonazepam as an active ingredient. Clonazepam is used as anti-seizure medicine in adults and children.
It also affects neurotransmitters in the brain that may be unbalanced in patients with anxiety disorders. Klonopin is most commonly prescribed as an antiepileptic drug in the treatment of the Lennox-Gastaut syndrome (epileptic petit mal variant), akinetic and myoclonic seizures and for the treatment of panic disorders including agoraphobia. Klonopin indications are:
- Akinetic seizures
- Essential tremor
- Lennox-Gastaut Syndrome
- Manic Episode
- Panic disorder
- Rapid Eye Movement Sleep Disorder
- Tardive dyskinesia
- Tourette Syndrome
- burning mouth syndrome
- mixed episode
- myoclonic seizures
- refractory absence seizure
- restless leg syndrome
This drug is available in the form of tablet tablet and disintegrating (dissolving) tablet taken by mouth in doses of 0.5 mg, 1 mg and 2 mg. FDA approved clonazepam in 1975 under the brand name Klonopin. It is originally manufactured by Roche drug company.
Clonazepam is listed as a controlled substance because it’s possible for people to abuse the drug and cause dependency. In 2011, there were 76,557 emergency room visits resulting from the abuse or misuse of clonazepam, an increase of 122 percent from 2004.
How Klonopin and Xanax work in the body?
Alprazolam, the active ingredient of Xanax works as an agonist of benzodiazepine BNZ-1 receptors, which are responsible for induction of sleep and benzodiazepine BNZ-2 receptors which are responsible for motor coordination, anticonvulsant activity and memory functions.
BNZ1 and BNZ2 receptors are coupled with GABAA receptors, and when alprazolam binds to them it increases affinity of GABA neurotransmitter to its receptor places and thus its inhibitory effects. After that GABA opens the chloride channel, which results in a neuron’s membrane hyperpolarization and prevention of further cell excitation.
Clonazepam from Klonopin works by causing allosteric interactions between benzodiazepine receptors and gamma-aminobutyric acid (GABA) receptors in the CNS, enhancing the effects of GABA, which is the major inhibitory neurotransmitter in the brain.
Final results are increased inhibition of the ascending reticular activating system. Clonazepam block the cortical and limbic arousal that occurs following stimulation of the reticular pathways.
Differences and similarities between Klonopin and Xanax
Is Xanax and Clonazepam the same thing? Both medicines are central nervous system depressants and are classified as benzodiazepines. Chemically they are very similar. Clonazepam is 1,3-dihydro-7-Nitro-5-(2-chlorophenyl)-2H-1,4.benzodiazepin-2-one while alprazolam is 8-Chloro-1-methyl-6-phenyl-4H-S-triazolo(4,3-a)(1,4)benzodiazepine.
So, Clonazepam contain nitro group more than alprazolam, which in theory means that it should be more reactive than alprazolam. However, both compounds contain chloride atom that gives more reactivity to the drug.
Both drugs affect gamma-aminobutyric acid or GABA which is a major inhibitory neurotransmitter in the brain. This causes nerve impulses to slow down, resulting in a sedating, calming effect.
Drugs have almost same bioavailability of 80-90% after administration; they are both metabolized by Cytochrome P450 3A4 in the liver and both drugs are excreted through kidneys.
Both medicines are available only with a doctor’s prescription. Alprazolam is available only in tablet form while clonazepam is also formulated as sublingual tablet, intramuscular and intravascular injection.
Both drugs are addictive and may cause dependency and withdrawal symptoms if they are abrupt suddenly.
Main difference between these two medicines is in their label indications. While both drugs can be prescribed for the treatment of anxiety disorders including panic attacks, Klonopin can be also prescribed to treat seizure disorders such as: tremors, seizures, and spasticity and other conditions, including multiple sclerosis, epilepsy and Tourette syndrome.
The other difference is that Xanax has less duration of action, and will have effects only for a few hours, while clonazepam has a longer duration of action. Xanax has a half-life time of 9-16 hours while Klonopin’s half life time is about 18-39 hours depending on individual factors.
However, Xanax has faster onset of action than Klonopin, as it reaches maximum concentrations after approximately 1 hour compared to Klonopin that reaches after 2-3 hours.
When these drugs are taken during pregnancy, they may cause harm to the fetus. Newborns could also develop a tolerance to the medication when born and require treatment. Both medications can also pass into your breast milk and may cause slowed heartbeat, drowsiness, and breathing problems in nursing infants. It is never recommendable to take these drugs during pregnancy.
Which drug stay longer in the body, Xanax or Klonopin?
Xanax has an elimination half-life time of approximately 9 hours to 16 hours in healthy individuals. This means that for the most patients it will take 9 to 16 hours after ingestion to eliminate 50% of the drug from the body. However, in elderly subjects the elimination half-life time may exceed 16 hours, and among those with liver disease, the average half-life is 19.7 hours.
For most patients the average half-life of Xanax is around 12 hours. So the most patients will fully eliminate Xanax from their system within 4 days. However, term average clearance time doesn’t apply to everyone; that’s why some patients may eliminate Xanax from their system much faster than others.
This means that fast metabolizers may fully eliminate Xanax within 2 days. Many factors may influence on how much Xanax will stay in system. Those factors include: age, body weight, deposition of fats, genetics, liver and kidney function, metabolic rate, urinary pH, dosage and frequency of use and other drugs used at the same time.
Klonopin has much longer elimination half-life within the range of 30 to 40 hours after oral administration. This means that it may take between 1 and 2 days to eliminate 50% of the drug from systemic circulation. Based on its elimination time, it is estimated that Klonopin is likely stay in the body for 6.8 to 9.2 days after final dose is taken.
But, some other data also suggest that clonazepam may in some situations have a longer half-life between 19 to 60 hours. In that case, it could take between 4.3 and 13.75 days for complete Klonopin excretion.
Clonazepam is metabolized in the liver, forming a metabolite known as 7-aminoclonazepam. 7-aminoclonazepam half-life time is either shorter than, or similar to that of clonazepam. That’s why body will eliminate Klonopin, as well as its 7-aminoclonazepam metabolites within 2 weeks.
Klonopin and Xanax side effects
|Klonopin possible side effects||Xanax possible side effects|
|Somnolence (37%)||Drowsiness (41%)|
|Abnormal coordination (5-10%)||Headache (10-15%)|
|Ataxia (5-10%)||Depression (10-15%)|
|Depression (5-10%)||Diarrhea (10-15%)|
|Dizziness (5-10%)||Dry mouth (10-15%)|
|Fatigue (5-10%)||Constipation (10-15%)|
|Memory impairment (5-10%)||Confusion (5-10%)|
|Upper respiratory infection (5-10%)||Tachycardia (5-10%)|
|Confusion (1-5%)||Insomnia (5-10%)|
|Dysarthria (1-5%)||Blurred vision (5-10%)|
|Rhinitis (1-5%)||Nasal congestion (5-10%)|
|Coughing (1-5%)||Nausea/vomiting (5-10%)|
|Urinary frequency (1-5%)||Hypotension (1-5%)|
|Impotence (1-5%)||Akathisia (1-5%)|
|Decreased libido (1-5%)||Syncope (1-5%)|
|Increased salivation (frequency not defined)||Dizziness (1-5%)|
|Worsening tonic-clonic seizures (frequency not defined)||Increased salivation (1-5%)|
|Weight change (1-5%)|
Klonopin and Xanax withdrawal effects
Xanax and Klonopin may also cause withdrawal symptoms. However in lower rate, because these drugs are rarely used for a long-term. Patients who abruptly discontinued Klonopin or Xanax, in most cases experience rebound symptoms for which the drug was originally prescribed. These symptoms may include:
- increased anxiety
- more frequent panic attacks
- loss of appetite
Many of these symptoms pass with time, however some of them require medical help. One thing is certainly known, Klonopin and Xanax should never be discontinued abruptly. The best method for drug discontinuation is a slow, methodical decrease, over a period of time, under doctor’s supervision.
Which one is expensive, Klonopin or Xanax?
According to drugs.com:
- The cost for Klonopin tablet 0.5 mg is around $264 for a supply of 100 tablets
- The cost for Klonopin tablet 1 mg is around $300 for a supply of 100 tablets
- The cost for Klonopin tablet 2 mg is around $414 for a supply of 100 tablets
- The cost for Xanax tablet 0.25 mg is around $323 for a supply of 100 tablets
- The cost for Xanax tablet 0. 5 mg is around $400 for a supply of 100 tablets
- The cost for Xanax tablet 1 mg is around $533 for a supply of 100 tablets
- The cost for Xanax tablet 2 mg is around $902 for a supply of 100 tablets
Prices depend on the pharmacy you visit. Prices are for cash paying customers only and are not valid with insurance plans.
What are Klonopin and Xanax interactions with other drugs?
Xanax and Klonopin may interact with following drugs:
- Opioid analgesics such as: Codeine, Lortab, Morphine, Vicodin and OxyContin. These drugs may cause sedation and increase drowsiness in patients.
- Allergy and Cold preparations such as: Benadryl, Diabetic Tussin Night Time and Contac Day and Night Cold and Flu. Active ingredient in these products is diphenhydramine, which increases the risk of drowsiness.
- Acid Reducers such as: Prevacid, Prilosec, Zantac, Tums or Rolaids, Nexium, Mylanta and Maalox. These drugs may reduce acid amount in the stomach preventing Xanax absorption in bloodstream.
- Prescription sleep aids such as: Ambien, Lunesta, Sonata and Halcion. Taking these drugs with Xanax may increase the risk of severe side effects such as respiratory depression, bradycardia, coma and even death.
- OTC Sleep Aids such as: Melatonin, Simply Sleep, Unisom and Sleep Ease. These products may increase risk of causing sedation.
- Medications Containing Propoxyphene such as: Darvocet, Darvon, Balacet and Propacet.
Can Xanax and Klonopin be used during pregnancy and breastfeeding?
Xanax and Klonopin have been assigned to Pregnancy Category D by the FDA list of drugs, which means that there is positive evidence of risk to the fetus. The highest risk is if these drugs are used in moderate to large amounts during the first and third trimester of pregnancy.
Like other drugs in the class, pregnant women should only take Klonopin or Xanax if the benefits of the medication clearly outweigh any of the potential risks to the unborn baby. Babies born to mothers who used benzodiazepines the days before birth will in most cases have from trace to moderate of clonazepam or alprazolam in their blood, as these drugs may pass through placenta.
There are reported cases of infants who were lethargic and cry less than usual during their first few days of life before becoming irritable and difficult to console for several hours to days. However, there are serious side effects associated with this are very rare, although respiratory depression and low blood pressure do occur on occasion.
All benzodiazepines and also Klonopin and Xanax are excreted into breast milk therefore they can be ingested by infant in very small amounts. Concentrations are usually not lethal, but they can cause sedation and severe respiratory distress.
Warnings and precautions during Klonopin and Xanax use
- Patients should not take Klonopin or Xanax if they have acute narrow-angle glaucoma. Patients should tell their doctor about any other eye symptoms.
- Patients who have severe liver disease, lung disease or sleep apnea should not take Klonopin and Xanax
- You should inform your doctor if you have heart problems, alcohol or drug abuse, and depression before taking Klonopin or Xanax.
- Antifungal drugs such as itraconazole and ketoconazole should not be taken with Klonopin and Xanax
- Patients with seizures or epilepsy have to avoid Xanax
- Do not use Xanax or Klonopin if you are pregnant. This medicine can cause birth defects. Newborn may also become dependent on these drugs. These drugs can cause life-threatening withdrawal symptoms. Such newborns may need medical treatment for several weeks. You should tell your doctor if you are pregnant or plan to become pregnant. Use effective birth control to prevent pregnancy while you are taking Xanax or Klonopin.
- These drugs can pass into breast milk and may harm a nursing baby. You should not breast-feed a baby while you are taking Valium or Xanax.
Do Klonopin and Xanax interact with grapefruit juice?
Benzodiazepines such as Klonopin and Xanax may interact with grapefruit juice. Combining Xanax or Valium with Grapefruit can lead to significant drug interactions and that’s why they should not be used together. Antioxidants from grapefruit juice can block the action of the liver enzyme CYP3A4. This inhibition may in some cases last even for 1 day.
CYP3A4 enzyme is responsible for metabolism of medications, including Klonopin and Xanax. High amounts of grapefruit may inhibit the actions of this enzyme, reducing elimination of these drugs from the body.
Also, high amounts of grapefruit in the diet may lead to abnormally high and potentially toxic levels of Klonopin and Xanax. Grapefruit is also known to inhibit the metabolism of other drugs that include some antihypertensive drugs, cholesterol-lowering drugs and anti-anxiety drugs.
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