This is Chapter 7: Endocrine/Miscellaneous, and in this video we'll be discussing emergency medicines.
The four medications, we'll be discussing today
Make up the acronym 'LEAN', and so the first medication is lidocaine, also known as Solarcaine,
and that is a local anesthetic. As you'll recall from the video from Chapter 5: OTC Neuro Agents,
lidocaine is a local anesthetic of the amide type, and the amide just refers to its shape.
When it's an amide, it just means that it has less of an allergic reaction
potential then the ester type like benzocaine.
The 'E' stands for epinephrine, also known as an EpiPen,
and that's an adrenergic agonist,
which works by stimulating the sympathetic nervous system. As you'll recall, the sympathetic nervous system is our fight-or-flight
response, so epinephrine stimulates alpha 1 and alpha 2 and beta 1 and beta 2.
Atropine or AtroPen is an anticholinergic agent, and it works in the peripheral nervous system,
which is known for causing things like rest and digest.
Naloxone or Narcan, that's our last medication and that is an opioid antagonist.
Now we'll go over some practice questions regarding the medications in this video,
and we'll keep all the answers the same as we work through these questions.
'A medication that works by blocking axonal conduction is?'
A) will be lidocaine, B) will be epinephrine, C) will be atropine, and D will be naloxone.
The correct answer is A) lidocaine.
B), C) and D) (epinephrine, atropine, and naloxone) are all incorrect
because they work on synaptic transmission.
As you will recall from your neuro section, the neuron is the basic cell of the nervous system and
the nervous system works by sending signals through electrical impulses and then release of
neurotransmitters, so epinephrine, atropine, and naloxone all work on synaptic transmission - and the synapse
Is the just the gap between cells - so the way that those work is that they mostly work to
change the way the neurotransmitters are released, how they are stored, or how they bind to the next cell.
Lidocaine on the other hand works on axonal conduction.
The axon is the long protrusion that sticks out of the end of the neuron, and
it inhibits electrical impulses that are sent down the axon, so it works as an anesthetic and it blocks pain.
For the rest of the video, we will just change the questions to make each of the answers correct .
Practice question three - 'A sympathomimetic that increases blood pressure and heart rate and causes bronchodilation is?'
The correct answer is B) epinephrine.
A) is incorrect because it doesn't affect any of those things - it just blunts pain response.
Atropine can increase the heart rate, but it works on the parasympathetic nervous system,
and naloxone is incorrect because it works on opioid receptors.
Epinephrine is a sympathomimetic which means that it stimulates the sympathetic nervous system,
and it works to do all of the things listed in the question so since it stimulates alpha one receptors,
we get vasoconstriction of the vasculature
Since it stimulates beta 1 receptors in the heart, we see an increase in heart rate. Since it stimulates beta 2 receptors
in the lungs, we get bronchodilation.
Epinephrine is a really good drug to use for allergic reactions.
Practice question four - 'A medication that is known for its drying effect is?'
The correct answer is C) atropine
Lidocaine, epinephrine and naloxone are all incorrect as they really don't have any drying properties.
As you'll recall atropine is anticholinergic medication, so
this works in the parasympathetic nervous system.
The parasympathetic nervous system is known for causing functions that equate to rest and digest,
so we digest food,
works on excretion and things like that.
Cholinergic medications, which are parasympathetic drugs
activate the parasympathetic nervous system,so when we activate that system
we get wet effects, so we get sweating, crying,
urinating and digestion.
Since atropine is an anticholinergic and 'anti-' means opposite, we get the opposite effect of stimulating
the parasympathetic nervous system, so we get drying effects.
We see side effects like dry mouth, dry eyes and urinary retention. It can also cause confusion in the elderly.
Okay, last practice question - 'A medication that is used for opioid overdose is?'
The correct answer is D) naloxone
A) lidocaine is incorrect because it is an anesthetic.
B) epinephrine is incorrect because it's used in allergic reactions.
C) atropine is incorrect because it reverses cholinergic effects by a causing drying.
Naloxone is used to
antagonize the effects of opioids. Opioid overdose is pretty common in the news today.
The reason we can overdose on opioids is because too much opioids can cause respiratory depression and
slow heart rate, so then patients can be knocked unconscious, and it can even lead to death.
Naloxone binds opioid receptors to displace the opioid that is bound, and thus reverse the overdose.
The important thing to remember with naloxone is that it works for a really short amount of time, so it will knock
patients into withdrawal since we're knocking the opioid off of the opioid receptor and replacing it with Naloxone.
It's really important to get these patients to the hospital quickly to get further care.