Neonates and Infants – Pharmacology across the Lifespan (Nursing)

00:01 Okay, so let's start with the tiniest, but the cutest little patients that we have.

00:06 We're going to look at neonates and infants.

00:08 Now, stop for a minute, pause, go back and look at that sheet, and make sure you're very clear on the age definition that we're calling for neonates and infants.

00:18 Now, they're really cute, but their organ systems are really immature, and they have an increased sensitivity to drugs because their organs can't deal with medications like adult medic- -- adult organs can.

00:30 So here's a good example.

00:31 We talked about the variability of responses.

00:34 Absorption -- remember that – from route to the bloodstream is different with neonates and infants.

00:41 Absorption of IM drugs, which is an intramuscular injection, is slower in neonates, but faster in infants, if we compare it to adults.

00:51 So, if I give an IM injection to a neonate, their absorption is going to be slower than compared to adult.

00:58 If I give an IM injection to a infant, it's going to be faster than an adult.

01:05 Now, also, protein binding capacity is limited in these little guys in comparison to adults, so they have lots of extra free drug that's around it might be relatively high.

01:15 These are both a couple of reasons why their organ system immaturity gives us increased sensitivity.

01:22 Now, speaking of immaturity, the blood brain barrier – we wrote that on your slide as just BBB but the blood brain barrier is not fully developed, so neonates and infants are really sensitive to central nervous system medications, or CNS medications.

01:40 Remember, the junctions in that blood brain barrier, when it's fully developed, are really tight.

01:45 So medications have to go through the cells instead of having the big spaces that they have in other areas of the body.

01:52 But these little guys, these neonates and infants, those capillary beds are not as tight and the junction aren't as tight, so that immature blood brain barrier let's all kinds of medications into their brain.

02:04 So we have to be extremely careful with any CNS or central nervous system medications.

02:11 Now, the drug metabolism ability of neonates is lower, and they have an increased sensitivity to drugs that have hepatic metabolism.

02:20 So, because their drug-- their livers are immature, that's the – the liver should be the one that metabolizes those drugs and their liver just isn't quite up to speed yet because they're still immature.

02:33 They don't process those drugs as well, so that's why they have an increased sensitivity with drugs that are normally processed by the liver.

02:41 And lastly, we're looking at renal excretion.

02:44 Remember, we've looked at absorption, distribution, and metabolism in neonates and infants; and the fourth process is renal excretion.

02:52 Now, renal excretion in neonates and infants is relatively lower.

02:56 Remember, those systems, those kidney systems are just kind of getting up to speed because they're immature.

03:03 All right. Now, I want you to take a chance to pause and reflect and think about this question.

03:08 What are the three causes of neonates' and infants' increased sensitivity to drugs? Now, I know there's more than three, but I just want you to pause and reflect and see if you can write three examples of neonates and infants increased sensitivity to drugs in the margin of your notes.

03:31 Okay, well done that you took the time to do that.

03:34 That is the best way for you to start encoding that information in your brain so you can learn to apply it.

03:40 So let's look at more than three reasons and see how many of these you're able to get.

03:44 All of these are correct.

03:46 So causes of increased sensitivity to drugs in neonates and infants are, number 1, organ system immaturity and increased sensitivity to drugs.

03:56 Number 2, absorption of IM drugs is slower in neonates, but faster compared to adults.

04:04 Protein binding capacity is limited, so in comparison to adults, the concentration may be relatively high.

04:11 Remember, the concept is, why are these neonates and infants' increased sensitivity to drugs, what causes it? So the first three we came up with: organ system immaturity, absorption of IM drugs is different, and their protein combining capacity is limited.

04:28 All right. Now see, if you got any of these three.

04:30 Their blood brain barrier is not fully developed.

04:34 So that makes them really sensitive to central nervous system drugs.

04:38 Neonates' drug metabolism abilities are lower, so they have an increased sensitivity to drugs that have hepatic metabolism.

04:45 And finally, of the top six reasons, renal excretion is relatively lower in neonates.

04:52 Now, if you didn't get all six of those, just take a second and jot down notes to yourself, because the time you take to think about these reasons and write them down will help you remember them, as you go forward.