When you consider that the average 65-year-old American takes 13-16 medications at any given time, the worry of polypharmacy, drug interactions, and adverse reactions is very real!
At this point in the course, we have considered many aspects of pharmacokinetics. We have studied “rapid metabolizers” of codeine in unit 2, and you are currently studying renal drugs and the most important determinant of drug dosing in the elderly–creatinine clearance. Recently, new renal markers have been identified that can help monitor kidney function (and ostensibly, drug clearance) even before serum creatinine levels increase. In the cardiac drugs, we have examined the different aspects of warfarin metabolism in patients who have varying responses to that drug. And by now, hopefully, you are also getting an appreciation for a certain handful of drugs that you must always be mindful and careful of–the drugs that are potent inhibitors or inducers of certain P450 enzymes and P-glycoprotein.
In this post, I would like you to share a clinical experience you may have had where pharmacokinetics have had to be considered and why. It is not enough to post “I had to measure CrCl because the patient was old”. Think about how drugs may interact and cause adverse reactions, near-misses, or events that necessitate a re-visit to a health care provider.
Your initial post requires a reference other than your textbook, and remember, side effects are not necessarily pharmacokinetics! Pharmacokinetics has to do with absorption, distribution, metabolism and excretion–drugs that are affected by those may have an adverse reaction in your patient–but why? Make sure your post is not simply describing a side effect (or allergic reaction) unless you can tie it to pharmacokinetics.
