This is Chapter Five: Neuro and in this video, we'll be discussing the drug class
benzodiazepines. Benzodiazepines are known as sedative-hypnotics.
The only difference between a sedative and a hypnotic is the dosing, so drugs are sedatives at lower doses
and they are considered hypnotics at higher doses.
Before we had
benzodiazepines for sedation and
the use of hypnotics, we used to prefer the drug class called barbiturates, but those have really fallen out of favor.
Barbiturates were known for causing a lot of respiratory depression because they were infinitely able to
depress the central nervous system, so
they had a pretty high risk of suicide
and it didn't take a lot of medication to overdose and lose the ability to breathe.
They were also high risk for abuse and they had a lot of dru-drug interactions through the liver and different enzymes that metabolize drugs.
Now,
benzodiazepines are a lot better and we use them a lot more often
because they only have a finite ability to depress the central nervous system,
so there's less of a chance for that respiratory depression, so it makes them a little bit safer,
and there are a lot less drug drug interactions.
Today, we typically use
benzodiazepines for anxiety and insomnia.
None of the medications we'll discuss today have the indication for insomnia,
but they can be used for that.The different reasons that we pick the different
benzodiazepines is typically for the duration of action needed, so short-acting
benzodiazepines last between 1 and 12 hours,
and they can be used for panic attacks or for seizures that are known as status epilepticus.
The medium or intermediate acting
benzodiazepines can work for between 12 and 14 hours, and those can be used for anxiety, insomnia, and
panic disorder as well as seizures.
The long-acting benzodiazepines can work from 40 to
250 hours and can be used for alcohol withdrawal among other things.
The four benzodiazepines we'll discuss today are alprazolam
with the brand name Xanax, midazolam or Versed,
clonazepam or Klonopin, and lorazepam or Ativan. We can remember that these are
benzodiazepines by their stem - either that '-azolam' stem, or the '-azepam' stem.
Now we'll go over five practice questions,
so the first practice question is: 'A benzodiazepine
that is metabolized by the liver is?' and so for the remaining questions, A) will be alprazolam, B) will be midazolam
C) will be clonazepam, and D) will be lorazepam.
The correct answer is D) lorazepam. Lorazepam is metabolized by the liver. There's three different
benzodiazepines that are metabolized by the liver and we can remember them as 'LOT, so it is lorazepam,
oxazepam, and temazepam. The rest are metabolized by the kidneys. A reason we might prefer a drug that is
metabolized by the liver is because in
certain patients, especially the elderly population, they are more likely to have
renal impairment and worse kidneys, so in patients that are older
It would take longer to clear the drug and so we might have more of a sedative effect in those patients,
so that's one reason we might consider using a medication that's cleared by the liver instead.
Lorazepam is an intermediate acting
benzodiazepine and we can use it for alcohol withdrawal and anxiety as well as seizure disorders.
For the next three questions, we'll have the same answers in the same order
and we'll just change the question to make the answer correct.
So the next question, make A) correct: 'A benzodiazepine
that is intermediate acting and available as an oral solution is?' and the answer is A) alprazolam.
Alprazolam is pretty cool in that it has quite a few different dosage forms - we can have an extended-release tablet, a
disintegrating tablet for those who can't swallow, as well as a solution for those who can't swallow pills.
Midazolam is short acting so that's not correct and clonazepam and lorazepam are both intermediate acting,
but clonazepam is only available as a tablet. Lorazepam does have some different dosage forms namely
one that can be injected, but it is not available as a solution.
We typically use alprazolam for anxiety disorders and panic disorders.
So question three make B) correct:
'A benzodiazepine that is short acting and can cause anteretrograde amnesia is?' and the answer is B) midazolam.
so A)
B) and D) are incorrect because they are all intermediate acting, and while all of the all of these
benzodiazepines can be associated with the amnesia, midazolam is pretty well known for
causing this so anteretrograde amnesia.
'Ante-' means before, so you can think of it as maybe the ante in poker that you
bet before the dealer deals, and so anteretrograde amnesia
just means that after you take the medication, you are unable to form new memories,
so if you do things shortIy after taking the medication, you might not remember that you did them.
Midazolam can also be used in the hospital especially for sedation procedures like when we're intubating someone.
So question four make C)
correct: 'A benzodiazepine
that is used for seizures is?' and select all that apply. The correct answer is C) clonazepam and D) lorazepam
Those are both indicated for seizures,
especially for status
epilepticus.
A) is incorrect -
alprazolam is only indicated for anxiety - and B) midazolam is incorrect because it is used for anxiety and also
induction of anesthesia.