Intravenous vs. Oral Medications – Elimination Kinetics

00:01 Let's talk about intravenous versus oral medications. You can see here in the chart how intravenous drugs and oral drugs differ in terms of their serum levels.

00:12 When we give oral drugs, even as often as every 4 hours, we are not going to get as smooth the curve in terms of your blood levels as you will with intravenous drugs. When we stop the drug at hour 14, you can see that both go through first order elimination kinetics and both will end up with roughly zero drug in the body at roughly the same time.

00:39 Let's do a peak and trough evaluation. So the peak level is the maximum level that you want that drug at, and the trough is the lowest level that you want that drug at.

00:51 In this particular case, you have a minimum toxic concentration and a minimum effective concentration.

00:57 And in between those two values is our therapeutic window. We want peak and trough levels to be in that range.

01:04 We can do calculations to figure out what our dosing regimen and our frequency and our doses going to be.