How clonazepam works
Like other benzodiazepines, clonazepam binds to the docking sites (receptors) of the nerve messenger gamma-aminobutyric acid receptor (GABA). As a result, it exerts anticonvulsant (antiepileptic), antianxiety (anxiolytic), sedative (sedative), and muscle relaxant (muscle relaxant) effects.
The nerve cells of the brain communicate with each other via messenger substances known as neurotransmitters. In the process, a nerve cell releases these excitatory or inhibitory neurotransmitters at a contact point (synapse) and the downstream cell, which perceives the messenger via docking sites (receptors), is subsequently excited or inhibited.
One of the most important inhibitory neurotransmitters is GABA. This neurotransmitter binds to GABA receptors, among others. These can be influenced by many substances, for example non-specifically by alcohol or specifically by barbiturate sleeping pills such as phenobarbital.
Benzodiazepines such as clonazepam also bind to the GABA receptor. They thus enhance the effect of the naturally present GABA and are thus suitable as sleeping pills, sedatives and anticonvulsants.
Absorption, degradation and excretion
In the liver, clonazepam is converted into ineffective degradation products and then excreted mainly in the urine, to a lesser extent also in the stool. After one and a half days, the clonazepam level in the body has decreased by half again (half-life).
When is clonazepam used?
In Germany, clonazepam is only approved for the treatment of various forms of epilepsy in adults and children (including infants) when the epilepsy has not responded to other medications.
Clonazepam can be used either alone (monotherapy) or together with other medications (add-on therapy). In certain forms of epilepsy, the active ingredient is indicated exclusively as an add-on therapy.
Clonazepam is also approved for epilepsy treatment in Austria and Switzerland.
In several countries as well as in Germany, clonazepam is also used “off-label” (outside the respective approved indications) for the treatment of anxiety disorders, sleepwalking and movement disorders (restless legs syndrome, spasms of the masticatory muscles, sitting restlessness), among others.
How clonazepam is used
Treatment with clonazepam is started gradually:
Adults usually begin therapy with 0.5 milligrams of clonazepam twice daily. The dosage is then slowly increased over several weeks until the optimal effect is achieved. The total daily dose of eight milligrams – divided into three to four individual doses – should not be exceeded. It is taken independently of meals with sufficient fluids.
Younger patients receive a reduced dose. Children under six years of age and patients with swallowing difficulties may take clonazepam drops instead of tablets.
As with other anticonvulsants, treatment must not be stopped abruptly, as this may provoke seizures. To stop treatment, the dosage must be gradually reduced (“tapering”).
What are the side effects of clonazepam?
The side effects of clonazepam are similar to those of other benzodiazepines. Fatigue, drowsiness, faintness, dizziness, lightheadedness, and weakness are common, especially at the beginning of treatment and at higher doses.
What should I be aware of when taking clonazepam?
Contraindications
Clonazepam must not be used in:
- severe respiratory dysfunction (respiratory insufficiency)
- severe liver dysfunction (hepatic insufficiency)
- known dependence on medicines, drugs or alcohol
Drug interactions
If clonazepam is used in addition to other agents for epilepsy, lower doses of the agents are usually sufficient because of the mutual effect enhancement. This may improve the tolerability of the therapy.
Drugs that lead to higher concentrations of degrading enzymes in the liver (so-called enzyme inducers) can thereby increase the degradation of clonazepam – its effect is reduced. Some of these drugs are also used in epilepsy, for example phenobarbital, phenytoin, carbamazepine and oxcarbazepine.
Because of the risk of unpredictable interactions, alcohol should never be consumed during treatment with clonazepam.
Driving and operating heavy machinery
Even when used as directed, clonazepam may impair alertness and responsiveness. Therefore, especially during the first days of therapy, patients should not drive vehicles or operate heavy machinery.
Age Limitation
Clonazepam may be used as early as infancy, if necessary. Dosage is based on body weight.
Pregnancy and lactation
If possible, therapy with clonazepam should not be started during pregnancy. However, women who are already stable on clonazepam can continue to take clonazepam during pregnancy. The lowest effective dose should be aimed for.
Small amounts of the active ingredient pass into breast milk. If continued use is absolutely necessary during breastfeeding, women should wean beforehand. Due to the long half-life of clonazepam, there is a risk that the active substance will accumulate in the child’s body.
Preparations containing clonazepam are subject to prescription in Germany, Austria and Switzerland.
How long has clonazepam been known?
After the market launch of the first benzodiazepine (chlordiazepoxide in 1960), numerous other benzodiazepines were developed with different properties and profiles of action. The active ingredient clonazepam was patented in 1964 and marketed in the USA from 1975.
