Tuesday, October 19, 2010

Drug Interactions- Wading through the data

Posted by Sarah Thiel at Tuesday, October 19, 2010

For my third rotation, I have been working on drug information with LexiComp. My preceptor works specifically on all topics related to drug interactions, including writing the monographs seen in LexiInteract.

It can be crazy to think about, but all those useful resources, such as Micromedex, the Drug Information Handbook, and Facts and Comparisons, all had to be written by somebody.

And while as students we may use those resources on a daily basis, it is easy to take for granted the concise and direct nature of the text and all the long hours put into reading the research that is the foundation for such resources.

One of the most valuable skills all students should take away from their drug information rotation is the ability to critically evaluate literature and to be able to consolidate those tens to possible hundreds of pages of research to a concise but thorough piece of writing.

Critically evaluating and reviewing literature is more than "there were some typos and the funding source could have biased the results". You have to dig so much deeper.

For drug interactions specifically, there are many factors that can influence findings. Many of the cytochrome P450 enzymes are polymorphic, resulting in different phenotypes of enzymes. Medications that are classified as "inhibitors" don't all inhibit to the same degree. Concentrations used for in vitro experiments may not represent concentrations seen in humans. Transporter proteins, both efflux and uptake pumps, can also influence magnitudes of interactions.

Then there is the issue of conflicting results: study A found increased risks of poor outcomes from combination therapy of drugs X and Y, but study B found no difference in risks. Now it's your job to wade through the data, the study design, and yes- even the statistical methods, to understand the possible reasons behind the difference in results. Because what would you tell a physician who is asking you, the pharmacist, if they could put a patient on drug Y who is already on drug X? Clearly, knowing how to critically evaluate the literature and explain it to another person in a concise manner can further make the pharmacist a critical member of the health care team.

So despite the hundreds of hours I've spent running PubMed literature searches, reading primary research, writing and revising interaction monographs, I can be assured that I'll never read a research paper the same way I did prior to this rotation.

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