Benzodiazepines are medications that help calm and depress the central nervous system. This review will discuss the mechanism of action of benzos, what conditions they treat, nursing implications, side effects, and patient education.
Don’t forget to take the Benzodiazepines NCLEX questions quiz after reviewing this material.
Benzodiazepines Pharmacology Nursing Review
Benzodiazepines (Benzos, BZDs): a class or group of medications that calms the central nervous system (CNS). Therefore, they are CNS depressants: anxiolytic and sedative-hypnotic medications.
Results in a calmer central nervous system and produces a sedative type or tranquilizing effect on the body. There are different types of Benzos with various levels of potency….some are very potent while others are mild, some act fast with a short duration while others act slowly with a long duration.
How to recognize them? The middle of the generic drug name will have either “ze” or “zo” and most end with “pam” or “lam” except, Clorazepate and Chlordiazepoxide.
Popular ones you may encounter in practice are: Alprazolam, Lorazepam, Clonazepam, Temazepam, Diazepam, Midazolam
Due to their ability to depress the central nervous system they can be used to treat a variety of disorders where there is too much CNS stimulation occurring. Remember various types of Benzos are available and some are better at treating certain conditions.
- Alcohol withdraw
- Panic attacks
- Before a procedure with moderate sedation
Can be given various routes IV, PO, IM, rectally etc.
How do they work….mechanism of action?
Benzos amplify the effect of the neurotransmitter GABA (gamma-aminobutyric acid). GABA is an inhibitory neurotransmitter.
What is a neurotransmitter? It’s a chemical agent produced and released by a neuron that TRANSMITS messages to a specific structure that it was designed to target via that target’s special receptors. Many times the target is another neuron.
Neurotransmitters can be grouped as being excitatory or inhibitory. Some neurotransmitters can do both depending on where they are acting in the body. However, GABA is one of the main types of neurotransmitters in the body that is an inhibitory neurotransmitter.
What’s the difference between excitatory and inhibitory neurotransmitters?
Excitatory: they excite and increase the potential of an action… like the neuron firing and the message being carried out
- If we were treating anxiety or seizures, we wouldn’t want to excite the neurons even more but calm them down.
Inhibitory: they impede and decrease the potential of an action by preventing an action…hence stopping the message from being carried out….this helps create a CNS depressant state or calming effect.
The neurotransmitter GABA binds to GABA receptors. Many GABA neurons are located in the limbic system, which is the place in our brain that helps us process our emotions and the way we behave. Now there are two types of GABA receptors: GABAA and GABAB receptors
Benzos influence GABAA receptors.
So, let’s talk in depth about these receptors….
GABAA receptors are ligand-gated or also called ionotropic receptors. These terms describe how the receptor works to complete its job. When these GABA receptors are influenced by BENZOS and binding occurs a channel opens to allow the movement of ions, specifically chloride (CL-). This is going to majorly affect how the neuron fires (hence it will inhibit action potential).
Now let’s talk a closer look at these types of receptor and how they work to depress the CNS.
GABAA receptors have the following characteristics that allow them to work:
The receptor is designed with 5 sections. Notably called subunits:
- 2 alpha “α” subunits
- 2 beta “β” subunits
- 1 gamma “γ” subunit
In between these subunits, is a hole (pore). And when the channel opens due to binding, it allows chloride to move through the channel into the cell. This causes hyperpolarization and is responsible for inhibiting potential action…hence providing calm, tranquilizing effects.
It has a total of three binding sites: Two sites for GABA (the neurotransmitter) and one special site for Benzodiazepine (it has its own site). The two GABA binding sites are found between each alpha and beta subunit, and the one Benzo site is found between the alpha and gamma site.
So, what happens? Neurons release the neurotransmitter GABA. GABA rains down onto GABA receptors and finds its binding site between the alpha and beta subunits. Now if a BENZO has been administered, its chemical substance that is hanging out finds its special binding site between the alpha and gamma subunit.
Then due to this binding the channel opens and through the pore of the receptor, chloride flows down into the cell and hyperpolarizes it. This makes it negative and decreases the firing potential, hence calm, tranquilizing effects. Therefore, it’s important to note that the binding of benzos at its site, plus GABA binding at their own sites will create this exaggerated effect of how GABA normally chills the body out….which results in: decreased anxiety, stops seizures, helps a patient sleep, calms the withdrawal effects of alcohol etc.
Now let’s talk about nursing responsibilities, side effects, and education pieces for the patient.
BEERS list: not appropriate for older adults (this is a list of medications created by the American Geriatric Society that list medications that should not be prescribed for older adults but avoided due to the older adults inability to handle the medication)
- Older adults are at risk for toxicity, dependence and abuse, increased risk of falls and accidents, and altered mental status etc. If you would like to see all the medications listed on this list by the American Geriatric Society you can access it here: https://geriatrictoolkit.missouri.edu/drug/Beers-Criteria-AGS-2019.pdf
ETOH, opioids, and other CNS depressants should be avoided while taking this medication…EDUCATE this to the patient…increases risk for overdose and death (FDA has a black box warning about this)
Not recommended for long-term usage due to the high risk of dependence, withdrawal symptoms, and abuse…best for short-term usage
- Can’t abruptly just stop the medication if taking over a period of time MUST be tapered off
Zzzs (sleeping), hypnotic/sedative effect: educate about avoiding activities that require focus and coordination
Overdose reversal with antidote: Flumazenil (use with caution…assess if benefits greater than the risks)
- Be familiar with signs of toxicity…can happen due to inability to handle the medication like older adults are more susceptible or when dependence of the drug develops and abuse occurs (patient will need higher dosage to keep getting the same effect) : “Abused”
- Altered mental status (very drowsy or coma, agitated, confused)
- Unable to walk or coordinate movements (ataxia)
- Speech garbled or slurred
- Experience hallucinations and memory loss
- Decreased respirations
American Geriatrics Society 2019 Updated AGS Beers Criteria® for Potentially Inappropriate Medication Use in Older Adults. (2019), 67(4), 680. https://doi.org/10.1111/jgs.15767
Department of Justice Drug Enforcement Administration. (2020). Benzodiazepines Drug Fact Sheet [Ebook] (p. 1). Retrieved 2 March 2021, from https://www.getsmartaboutdrugs.gov/sites/getsmartaboutdrugs.com/files/files/Benzodiazepenes-2020.pdf.
FDA Expands Boxed Warning to Improve Safe use of Benzodiazepine Drug. U.S. Food and Drug Administration. (2020). Retrieved 2 March 2021, from https://www.fda.gov/drugs/drug-safety-and-availability/fda-requiring-boxed-warning-updated-improve-safe-use-benzodiazepine-drug-class.