Benzodiazepine anticonvulsants refer to those benzodiazepines that are also effective at controlling or preventing convulsions or seizures.
All benzodiazepines act on gamma-aminobutyric acid-A (GABA-A) receptors, but there are several different GABA-A receptor subtypes. Benzodiazepines can differ in their affinity for some of these subtypes which results in them having different effects.
Research has shown that one of the GABA-A subtypes, called α-1-GABA-A, appears to be responsible for moderating sedation, amnesia, and anticonvulsant activity. Another subtype, called α-2-GABA-A, moderates for anxiety.
Benzodiazepines that are classified as benzodiazepine anticonvulsants have a higher affinity for α-1-GABA-A. Examples of benzodiazepine anticonvulsants include clobazam, clonazepam, clorazepate, diazepam, lorazepam, and midazolam.
What are benzodiazepine anticonvulsants used for?
Diazepam and lorazepam are usually used for the management of seizure emergencies. Midazolam may sometimes be used as an alternative to these two benzodiazepine anticonvulsants, or for the treatment of status epilepticus (prolonged, consecutive seizures with no intermittent recovery of consciousness).
Clobazam, clonazepam, and clorazepate may be used in some chronic epilepsy conditions, such as partial and generalized seizures that have not responded to other medications and Lennox-Gastaut syndrome, as a preventive medication.
Benzodiazepine anticonvulsants may also be used to manage febrile seizures, acute repetitive seizures and alcohol withdrawal seizures.
What are the differences between benzodiazepine anticonvulsants?
Benzodiazepine anticonvulsants vary widely with regards to their absorption from the gastrointestinal tract into the blood stream, how quickly they start to work, and how long they work for.
Some are metabolised by the liver to active metabolites – these are breakdown products of the main drug that still have activity in the body. Benzodiazepine anticonvulsants that are metabolised into active metabolites include diazepam and clobazam. These benzodiazepines or their metabolites can persist for several days.
Common Benzodiazepine Anticonvulsants Available in the U.S.
|
Generic Name |
Brand Name |
Half-life* |
|
*The half-life is the amount of time it takes for half of the drug to be eliminated from the body. The shorter the half-life, the quicker the drug is eliminated. |
|
clobazam |
Onfi |
71-82h (long-acting) |
|
clonazepam |
Klonopin |
20-50h (long-acting) |
|
clorazepate |
Tranxene T-Tab |
20-100h (long-acting) |
|
diazepam |
Valium |
20-100h (long-acting) |
|
lorazepam |
Ativan |
10-20h (medium-acting) |
|
midazolam |
Generic |
2.5h (short-acting) |
All benzodiazepines are listed as DEA scheduled IV controlled substances. As controlled substances, all benzodiazepines have the potential for abuse, addiction and diversion.
Are benzodiazepine anticonvulsants safe?
Benzodiazepine anticonvulsants are potentially addictive and the risk of becoming emotionally and physically dependent on them increases the more you take. In addition, tolerance can develop with their use. This is when the same dose no longer gives the same effect, and a dosage increase is needed to ease symptoms again.
Benzodiazepine anticonvulsants such as diazepam, lorazepam, and midazolam are usually only given for seizure emergencies, and for a very short time (just one or two doses). The risk of becoming addicted to these drugs during this time is negligible.
Benzodiazepine anticonvulsants such as clobazam, clonazepam, and clorazepate may be used long-term in some seizure disorders that are unresponsive to typical anticonvulsants. In this situation, the benefits of these benzodiazepine anticonvulsants at preventing seizures are considered to outweigh their long-term risks.
What are the side effects of benzodiazepine anticonvulsants?
Drowsiness, sleepiness, or dizziness are the most common side effects reported. This can make it dangerous for people taking benzodiazepine anticonvulsants to drive or operate machinery or perform other hazardous tasks. Alcohol may potentiate these effects.
Other commonly reported side effects include:
- amnesia (forgetfulness)
- confusion
- constipation
- nausea
- sexual dysfunction
- unsteadiness when walking or standing
- unusually slow and shallow breathing
- vision problems (blurred or double vision).
Withdrawal symptoms may occur with abrupt discontinuation – symptoms may include convulsions, cramps, insomnia, sweating, tremors, and vomiting.
Rarely, benzodiazepine anticonvulsants may cause agitation, anxiety, or hallucinations in some people.
