Critical Care Paramedic 6 Introduction to Pharmacology Part 2
I’m going to go ahead and get started here. I’m going to talk a little bit about we’re going to talk about a little bit review things, give a couple cases, and then we’re going to start talking right away. So we talked about pharmacokinetics a little bit in the first lecture, bioavailability,.
We talked about half lives. A little bit of definitions before we get started, related to whether a drug is an agonist, antagonist, partial agonist, or antagonist agonist, at the receptor site. And you’ll see me talk a little bit more about the specific drugs and where they work. But this is a little bit to introduce you.
To the different opioids and narcotics I’m going to be talking about, and specifically where they work. And it’s important to know how these drugs work, because then you can add additional medications and the medications that you’re going to be adding, you’ll know specifically how they work in the body and whether you’re causing additional harm to the patient.
Or actually treating them for their condition. So a simple definition with an agonist is, a medication binds to a specific receptor site and it actually stimulates this receptor site, so you get more activity on it. An antagonist is a drug actually binds to that receptor site, or kicks the drug out that binds that receptor site, and you get the opposite effect.
So a really simple definition. Morphine is an agonist at a specific receptor. In our CNS, it’s called the mu receptor. It’s associated with relieving pain. Naloxone, OK, that is an antagonist drug that will kick out whatever has bound to that mu receptor, and then you get the opposite action. OK.
Partial agonist, I have a couple examples of that. But that would be something that maybe weakly binds to not necessarily the specific receptor, but maybe a side part of the receptor. It doesn’t initiate as much stimulation, and this full stimulation that you would a complete agonist. OK.
And then a partial agonist would be the opposite of that. An antagonist and agonist effect so even though I’ve just given an example of just a mu receptor, there’s a lot of different receptors that are associated with where opioids bind in the CNS. OK. Now some of these receptors have different properties to them, and some of them actually have negative properties to them.