Benzodiazepines are a class of drugs used to treat generalized anxiety disorder, tension, insomnia, seizure disorders, procedural/surgical sedation or amnesia, skeletal muscle spasm, tremor, and delirium (Comerford & Durkin, 2022). The precise action of benzodiazepines is not fully understood but they have been found to work selectively on polysynaptic neuronal pathways throughout the central nervous system (CNS). Let’s take a closer look at the mechanism of action for benzodiazepines.
Mechanism of Action
Benzodiazepines enhance or facilitate the action of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter in the CNS that suppresses the activity of nerves. The drugs appear to act at the limbic, thalamic, and hypothalamic levels of the CNS to produce anxiolytic, sedative, hypnotic, skeletal muscle relaxant, and anticonvulsant effects (Comerford & Durkin, 2022).
At the cellular level, the speed of impulses from a presynaptic neuron across a synapse is influenced by the number of chloride ions in the postsynaptic neuron. The passage of chloride ions into the postsynaptic neuron depends on the inhibitory neurotransmitter GABA. When GABA is released from the presynaptic neuron, it travels across the synapse and binds to GABA receptors on the postsynaptic neuron. This binding opens the chloride channels, allowing chloride ions to flow into the postsynaptic neuron, resulting in a slowing of the nerve impulses. The result is a different type of depression. Benzodiazepines bind to receptors on or near the GABA receptor, enhancing the effect of GABA and allowing more chloride ions to flow into the post-synaptic neuron. This depresses the nerve impulses, causing them to slow down or stop.
Drugs and Indications
| Benzodiazepine Drugs and Indications (Facts and Comparisons, 2021; Comerford & Durkin, 2022) |
| Generic Name |
Brand Name |
FDA-Approved Indications |
| Alprazolam |
Xanax® |
Anxiety, panic disorder |
| Chlordiazepoxide |
Librium® |
Anxiety, alcohol withdrawal |
| Clobazam |
Onfi®, Sympazan® |
Seizure disorder |
| Clonazepam |
Klonopin® |
Anxiety, panic disorder, seizure disorder |
| Clorazepate |
Tranxene® |
Anxiety, seizure disorder |
| Diazepam |
Valium® |
Anxiety, muscle relaxant, procedural anxiety/surgical sedation, seizure disorder |
| Estazolam |
N/A |
Insomnia |
| Flurazepam |
N/A |
Insomnia |
| Lorazepam |
Ativan® |
Anxiety, procedural anxiety/surgical sedation, seizure disorder |
| Midazolam |
Versed® |
Procedural anxiety/surgical sedation, seizure disorder |
| Oxazepam |
Serax® |
Anxiety |
| Quazepam |
Doral® |
Insomnia |
| Remimazolam |
Byfavo® |
Sedation |
| Temazepam |
Restoril® |
Anxiety, insomnia |
| Triazolam |
Halcion® |
Anxiety, insomnia |
Contraindications (Facts and Comparisons, 2021)
Benzodiazepine use is contraindicated in patients with a known hypersensitivity to any component of the drug; severe hypersensitivity to dextran or products containing dextran; pregnancy; acute narrow-angle glaucoma; untreated open-angle glaucoma; significant liver disease; infants younger than 6 months; myasthenia gravis; coadministration with CYP3A inhibitors; sleep apnea; and severe respiratory impairment.
Side Effects & Monitoring (Comerford & Durkin, 2022)
Major sides effects of benzodiazepines include drowsiness, impaired motor function, visual disturbances, and cardiovascular irregularities. Toxic doses may cause issues with short-term memory, confusion, severe depression, vertigo, slurred speech, bradycardia, respiratory depression, respiratory arrest, or severe weakness. Prolonged or frequent use may lead to the development of addiction and withdrawal symptoms with a decrease in dose or termination of therapy. The antidote for benzodiazepine overdose is intravenous flumazenil.
For complete information, please consult the drug’s specific package insert or the
Nursing2022 Drug Handbook® + Drug Updates.
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