Clonazepam 160micrograms/5ml oral suspension
Requires a prescription from a doctor or prescriber
Antiepileptic drugs
Minimal controls; includes benzodiazepines and anabolic steroids
Legal requirements and restrictions
Benzodiazepines and similar medicines. Subject to minimal controlled drug requirements.
Legal requirements
- Prescriptions valid for 28 days
- No controlled drugs register required
- No safe custody requirements
- Record keeping requirements for imports/exports
Other medicines in this category
Safety information for pregnancy and breastfeeding
Pregnancy
Breastfeeding
Always consult your doctor or midwife before taking any medicine during pregnancy or while breastfeeding. Source: DrugBank (CC BY-NC 4.0).
Official documents, adverse reaction reporting, and safety monitoring
Report a side effect
Submit a Yellow Card report to the MHRA
Official medicine documents
Safety monitoring data
Yellow Card reports
The MHRA Yellow Card scheme collects reports of suspected side effects from healthcare professionals and patients. View the Drug Analysis Profile (iDAP) for real-world adverse reaction data.
View Drug Analysis Profile
Suspected adverse reactions reported for Clonazepam
Browse all iDAP reports
Interactive Drug Analysis Profiles for all medicines
Report a side effect
Submit a Yellow Card report to the MHRA
Data from the MHRA Yellow Card scheme. A reported reaction does not necessarily mean the medicine caused it. Contains public sector information licensed under the Open Government Licence v3.0.
EudraVigilance
The European Medicines Agency (EMA) collects suspected adverse reaction reports from across the EU/EEA through the EudraVigilance system. Search for safety data on this medicine.
View EudraVigilance report
Suspected adverse reactions reported for Clonazepam
About EudraVigilance
Learn about EU pharmacovigilance and safety monitoring
EudraVigilance data is published by the European Medicines Agency (EMA). A suspected adverse reaction is not necessarily caused by the medicine.
1 branded products available
WHO defined daily dose (DDD)
8 mg
Not a recommended dose. The DDD is the assumed average maintenance dose per day for a drug used for its main indication in adults. It is a statistical measure used for research and comparison purposes only.
Source: WHO Collaborating Centre for Drug Statistics Methodology, distributed via NHS dm+d BNF mapping files. Contains public sector information licensed under the Open Government Licence v3.0.
Therapeutically similar medicines
Similarity based on WHO Anatomical Therapeutic Chemical (ATC) classification and NHS BNF section grouping. Source data: NHS dm+d via TRUD (OGL v3.0), WHO ATC/DDD Index.
NHS prescribing volume and spending trends
Clinical guidelines and formulary information
British National Formulary
Clonazepam
Source: British National Formulary, NICE. Joint Formulary Committee. Contains public sector information licensed under the Open Government Licence v3.0.
NICE clinical guidance(4)
Parkinson's disease in adults (NG71)
Unilateral MRI-guided focused ultrasound thalamotomy for treatment-resistant essential tremor (HTG474)
Restless legs syndrome: Oxycodone/naloxone prolonged release (ESNM67)
Epilepsies in children, young people and adults (NG217)
Source: National Institute for Health and Care Excellence (NICE). Contains public sector information licensed under the Open Government Licence v3.0.
Check stock at pharmacies and supply information
Pharmacy stock checkers
Search for this medicine at major UK pharmacy chains. These links open the retailer's own website — results depend on their current online catalogue.
Supply & product information
Official product databases and supply status monitoring
Pharmacy links redirect to the retailer's own search and do not represent real-time stock levels. emc (electronic medicines compendium) is operated by Datapharm Ltd. Shortage information sourced from NHS Specialist Pharmacy Service (SPS), sps.nhs.uk.
Codes for healthcare professionals and prescribing systems
These codes are used by healthcare IT systems and prescribers to identify this medicine.
NHS UK identifiers
Browse tools
SNOMED CT and dm+d codes from NHS TRUD (Technology Reference data Update Distribution), licensed under the Open Government Licence v3.0. BNF codes from NHS Business Services Authority (NHSBSA). ATC codes from the WHO Collaborating Centre for Drug Statistics Methodology (whocc.no).
Active and completed clinical studies from ClinicalTrials.gov
Source: ClinicalTrials.gov, a database of the U.S. National Library of Medicine (NLM), National Institutes of Health (NIH). Data accessed via ClinicalTrials.gov API v2. Trial information is provided for research purposes and does not constitute medical advice.
Pharmacology and chemical data from DrugBank
Key facts
Drug status
Approved
Major interactions
1 found
Half-life
30-40 hours
Mechanism
Gamma-Aminobutyric acid (GABA) is considered the principal inhibitory neurotrans…
Food interactions
3 warnings
Human targets
2 targets
Data: DrugBank · CC BY-NC 4.0
Pharmacokinetics at a glance
Absorption
1-4 hours
Half-life
30-40 hours
Protein binding
82–86%
Volume of distribution
3 L/kg
Metabolism
Elimination
50-70%
Clearance
55 ml/min
Pharmacokinetic data: DrugBank · CC BY-NC 4.0
Since being first patented in 1960 and then released for sale from Roche in the US in 1975,[T469,T472] clonazepam has experienced a storied history in the treatment of the aforementioned medical conditions. Now available as a generic medication, the agent continues to see exceptionally high use as millions of prescriptions are written for the medication internationally every year. Unfortunately, however, like most benzodiazepines, clonazepam use has also been associated with recreational use and drug abuse.[FDA Label][L5572,F3763,F3787,F3796]
Alternatively, some regional prescribing information note that clonazepam is indicated for all clinical forms of epileptic disease and seizures in adults, especially absence seizures (petit mal) including atypical absence; primary or secondarily generalised tonic-clonic (grand mal), tonic or clonic seizures; partial (focal) seizures with elementary or complex symptomatology; various forms of myoclonic seizures, myoclonus and associated abnormal movements.[L5572,F3796] Such regional label data also has clonazepam indicated for most types of epilepsy in infants and children, especially absences (petit mal), myoclonic seizures and tonic-clonic fits, whether due to primary generalized epilepsy or to secondary generalization of partial epilepsy.F3796
Known interactions with other medications. Always consult a healthcare professional.
Showing 50 of 1576 interactions
Increased frequency of seizures may occur in patients at supratherapeutic plasma concentrations. Benzodiazepine respiratory depressant effects are more serious when compounded in patients with respiratory disease.
An increased risk of congenital malformations associated with the use of benzodiazepine drugs like clonazepam has been suggested in several studies [FDA Label] [F3763, F3796]. There may also be non-teratogenic risks associated with the use of benzodiazepines during pregnancy [FDA Label] [F3763, F3796].
There have been reports of neonatal flaccidity, respiratory and feeding difficulties, and hypothermia in children born to mothers who have been receiving benzodiazepines late in pregnancy [FDA Label] [F3763, F3796]. In addition, children born to mothers receiving benzodiazepines late in pregnancy may be at some risk of experiencing withdrawal symptoms during the postnatal period [FDA Label] [F3763, F3796]. In general, it is best for patients who are of childbearing potential and also use benzodiazepines like clonazepam to discuss such matters with their health care professionals as careful consideration must be undertaken regarding the intersection of the risks of untreated seizure potential in the patient and any possible toxicity to the fetus [FDA Label] [F3763, F3796].
Although the active ingredient of clonazepam has been found to pass into the maternal milk in small amounts only, mothers receiving clonazepam should not breast-feed their infants [FDA Label] [F3763, F3796].
Since the possibility that adverse effects on the physical or mental development of the child could become apparent only after a number of years, the risk-benefit consideration of the long-term use of clonazepam in pediatric patients younger than five years of age is important [FDA Label] [F3763, F3796].
The pharmacological effects of benzodiazepines like clonazepam appear to be greater in elderly patients than in younger patients even at similar plasma benzodiazepine concentrations, possibly because of age-related changes in drug-receptor interactions, post-receptor mechanisms, and organ function [FDA Label] [F3763, F3796].
In general elderly patients should be started on the lowest possible dose of clonazepam and observed closely [FDA Label] [F3763, F3796]. There is an increased risk for falls and fractures among elderly and debilitated benzodiazepine users [FDA Label] [F3763, F3796]. The risk is increased in those taking concomitant sedatives, including substances like benzodiazepines, alcoholic beverages, and so on [FDA Label] [F3763, F3796].
Some oral LD50 values documented are >4000 mg/kg for the mouse model, >4000 mg/kg for the adult rat model, and >2000 mg/kg for the rabbit model F3763.
Subsequently, benzodiazepines like clonazepam can bind to benzodiazepine receptors that are components of various varieties of GABA(a) receptors [A175423, A175438, A175441, F3787, L5572, F3763]. This binding acts to enhance the effects of GABA by increasing GABA affinity for the GABA(a) receptor, which ultimately enhances GABA ligand binding at the receptors [A175423, A175438, A175441, F3787, L5572, F3763]. This enhanced ligand binding of the inhibitory neurotransmitter GABA to the receptors increases the aforementioned chloride ion conduction (perhaps reportedly via an increase in the frequency of the chloride channel opening), resulting in a hyperpolarized cell membrane that prevents further excitation of the associated neuron cells [A175423, A175438, A175441, F3787, L5572, F3763]. Combined with the notion that such benzodiazepine receptor associated GABA(a) receptors exist both peripherally and in the CNS, this activity consequently facilitates various effects like sedation, hypnosis, skeletal muscle relaxation, anticonvulsant activity, and anxiolytic action [A175423, A175438, A175441, F3787, L5572, F3763].
In particular, when out of the ordinary rapid and repetitive electrical signals are released in the CNS, it is proposed that the brain can become over-stimulated and ordinary functions are disrupted - resulting in seizure activity [A175441]. By enhancing the neuro-inhibitory activity of GABA, it is believed that clonazepam can facilitate in decreasing any excessive electrical nerve activity in the CNS that might be contributing to seizures [A175441]. Concurrently, it is also believed that clonazepam's actions in enhancing GABA effects may inhibit neuronal activity proposed to occur in amygdala-centered fear circuits - therefore assisting in the management of anxiety or panic [A175438].
Generalized EEG abnormalities are more readily suppressed by clonazepam than are focal EEG abnormalities such as focal spikes [L5572]. Clonazepam has beneficial effects in generalized and focal epilepsies [L5572].
How the body processes this drug — absorption, distribution, metabolism, and elimination
Hydroxylation at the C-3 position also occurs [F3763, F3796]. Hepatic cytochrome P450 3A4 is implicated in the nitroreduction of clonazepam to pharmacologically inactive metabolites [F3763, F3796].
Proteins and enzymes this drug interacts with in the body
Response to specific ligands is species-specific. Activated by naturally occurring steroids, such as pregnenolone and progesterone. Binds to a response element in the promoters of the CYP3A4 and ABCB1/MDR1 genes
Enzymes involved in drug metabolism — important for understanding drug interactions
Proteins that carry this drug through the body
PMID:19021548
Major calcium and magnesium transporter in plasma, binds approximately 45% of circulating calcium and magnesium in plasma (By similarity).
Potentially has more than two calcium-binding sites and might additionally bind calcium in a non-specific manner (By similarity). The shared binding site between zinc and calcium at residue Asp-273 suggests a crosstalk between zinc and calcium transport in the blood (By similarity). The rank order of affinity is zinc > calcium > magnesium (By similarity).
Binds to the bacterial siderophore enterobactin and inhibits enterobactin-mediated iron uptake of E.coli from ferric transferrin, and may thereby limit the utilization of iron and growth of enteric bacteria such as E.coli .
PMID:6234017
Does not prevent iron uptake by the bacterial siderophore aerobactin PMID:6234017
ATC N03AE01
Chemical identifiers
CAS, UNII, InChI Key and database cross-references
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Chemical identifiers
CAS, UNII, InChI Key and database cross-references
Linked compound data from DrugBank Open Data (CC BY-NC 4.0)
Clonazepam
Additional database identifiers
Drugs Product Database (DPD)
2192
ChemSpider
2700
BindingDB
50019213
ZINC
ZINC000003813003
HUGO Gene Nomenclature Committee (HGNC)
HGNC:4075
GenAtlas
GABRA1
GeneCards
GABRA1
GenBank Gene Database
X13584
GenBank Protein Database
31631
Guide to Pharmacology
404
UniProt Accession
GBRA1_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:4076
GenAtlas
GABRA2
GeneCards
GABRA2
GenBank Gene Database
S62907
GenBank Protein Database
386422
Guide to Pharmacology
405
UniProt Accession
GBRA2_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:4077
GenAtlas
GABRA3
GeneCards
GABRA3
GenBank Gene Database
S62908
GenBank Protein Database
386424
Guide to Pharmacology
406
UniProt Accession
GBRA3_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:4079
GenAtlas
GABRA5
GeneCards
GABRA5
GenBank Gene Database
L08485
GenBank Protein Database
182916
Guide to Pharmacology
408
UniProt Accession
GBRA5_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:4086
GeneCards
GABRG1
GenBank Gene Database
AK122845
GenBank Protein Database
193783776
UniProt Accession
GBRG1_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:4087
GeneCards
GABRG2
GenBank Gene Database
X15376
GenBank Protein Database
31637
UniProt Accession
GBRG2_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:4088
GeneCards
GABRG3
GenBank Gene Database
S82769
GenBank Protein Database
1754749
UniProt Accession
GBRG3_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:7968
GenAtlas
NR1I2
GeneCards
NR1I2
GenBank Gene Database
AF061056
GenBank Protein Database
3511138
Guide to Pharmacology
606
UniProt Accession
NR1I2_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:2631
GeneCards
CYP2E1
GenBank Gene Database
J02625
GenBank Protein Database
181360
Guide to Pharmacology
1330
UniProt Accession
CP2E1_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:7646
GeneCards
NAT2
GenBank Gene Database
D90040
GenBank Protein Database
219412
UniProt Accession
ARY2_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:2637
GenAtlas
CYP3A4
GeneCards
CYP3A4
GenBank Gene Database
M18907
Guide to Pharmacology
1337
UniProt Accession
CP3A4_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:399
GenAtlas
ALB
GeneCards
ALB
GenBank Gene Database
V00494
GenBank Protein Database
28590
UniProt Accession
ALBU_HUMAN
International reference pricing
Reference pricing from DrugBank. Prices are indicative and may not reflect current UK costs.
Source: DrugBank. Used under CC BY-NC 4.0 academic licence for non-commercial purposes.
DrugBank citations
If you use DrugBank data in your research, please cite the following publications: