Anxiolytics Flashcards
How do benzodiazepines work and where is their site of action?
- work to enhance GABA mediated inhibition
- binds between α1 - γ2 subunits on GABAa receptor complex
How do barbituates work and where is their site of action?
- works as a GABAa agonist and can directly open the Cl- channel at high doses
- binds to α or β subunit on GABAa receptor complex
Patient presents with altered consciousness and reduced respirations. Her brother says that he’s pretty sure she ODed on her anxiety pills, which are some class of benzo. What’s the dosing profile of benzos and what’s an important question to ask to determine prognosis of this patient? What drug do you want on hand to treat the overdose?
Benzodiazepines produce a “ceiling effect”; because they only potentiate GABA activity, and do not directly act on the channel itself, an overdose rarely leads to coma or death. If you have flumenazil handy, this is a benzo antagonist!
However, if the patient had recently been drinking alcohol or had taken a barbituate, all bets are off and can lead to death.
A patient presents to the ER with episodic seizures. Which benzodiazepines exhibit anticonvulsant activity?
diazepam and lorazepam
Your 50 yo patient is about to go in for their first colonoscopy and is wondering about the drugs that will be used. They are getting a benzodiazepine; which drug will they receive?
midazolam, which is given IV, has a short half life, and acts as an anesthetic while producing anterograde amnesia.
Which benzodiazepine is used as a sleeping aid and what is important about its pharmacologic properties?
triazolam, which has a short half life (2.9 hrs) so there is less likely to be a hangover effect produced upon awaking
How does diazepam’s actual half life vs. the functional half life compare?
Actual half life is 43 hrs, but active metabolites stick around for up to 100 hrs. This is a common theme among benzos, which produce unwanted daytime sedation
What is unqiue about lorazepam’s metabolism when compared to other benzodiazepines?
- metabolized directly to inactive glucuronides, so elimination is more predictable than other benzos
A 23 yo comes to your clinic asking for something to aid with her fear of flying. What is the most commonly prescribed drug for this?
alprazolam, with a half life of 12 hrs
What is the main use of BDZ-1 selective agonists? What is the main drug you should know in this class? What are the main precautions you should advise patients of before prescribing?
used for sleeping pills (there is little muscle relaxation or anticonvulsant activity)
- zolpidem! Many engage in sleep activities (walking, eating, driving - hide yo cakes, hide yo keys)
What is phenobarbital, what is it used for, and how long does it stick around in the body?
A barbituate used as anticonvulsant. Slow onset and half-life is 4-5 days.
What is thiopental and how is it used?
A barbituate used to induce anesthesia. Very lipid soluble, so onset is quick!
A patient presents with increasing episodes of anxiety over the past 2 months. They work as an airline pilot, so you decide against prescribing anything that could increase sedation. What do you prescribe?
- buspirone, which is a partial agonist of 5HT1a. No GABAa interaction!
Because benzos, barbs, and alcohol all work on the same receptor complex, what is something that you should be aware of as a prescribing physician?
cross tolerance develops, which can affect metabolism and/or receptor availability in the CNS
- NOTE: buspirone is an anxiolytic that will not produce any cross tolerance as it does not work on the GABA system.
List these benzos in order of shortest to longest acting functional effects in the body: A. lorazepam B. triazolam C. diazepam D. midazolam E. alprazolam
midazolam < triazolam < alprazolam < lorazepam < diazepam (as well as chlordiazepoxide and flurazepam)
