Many medications require a metabolic transformation before they can actually have a therapeutic effect. This transformation often involves what pharmacologists call a phase 1 reaction. There are three classes of phase 1 reactions: oxidation, reduction, and hydrolysis. All three reactions tend to make drugs more water soluble and thus more able to exert their effects within target cells.

A medication that requires such a metabolic transformation before it can work is called a prodrug. A wide variety of medications are prodrugs. Codeine, Tamoxifen, Enalapril, and L-DOPA are among the many medications that are administered as prodrugs and then metabolized to active, therapeutic compounds. (more…)

The July 18 New York Times “Science Times” features Nicholas Wade’s story “The Quest for the $1,000 Human Genome”. By some estimates, it now costs about $10-15 million to sequence an entire human genome (down from the $500 million it cost to do the first such sequence as part of the Human Genome Project). The production of a new generation of sequencing machines raise the possibility that the costs of a complete sequence will continue to fall. All of this begs the question of what we will do with all this information if it is available for approximately the same cost as a CT scan.

I talked with a molecular geneticist about this article, and he agreed that the $1,000 genome sequencing is not pie-in-the-sky. It may really happen.

This morning’s “Morning Edition” on National Public Radio did a story on pharmacogenetics that managed without being technical to touch on most of the important points. The story mentioned that the Mayo Clinic would be doing more of this testing in the future. Not mentioned was the fact that there are other institutions offering this service, including DNA Direct of San Francisco.

“Genes and Drugs” is a place for physicians and others learn more about how a person’s genetic makeup can affect his or her response to a particular medication–the field of pharmacogenetics or pharmacogenomics. For several dozen medications, there already exist tests that can help predict how a particular patient will respond to a specific drug. These tests have yet to have widespread adoption, but is inevitable that they will find their way into our clinical practice.

Your moderator here, is Alan Eshleman, MD, otherwise known as doctore. I’m neither a geneticist nor pharmacologist. Instead, I’m a board certified general internist with an abiding interest in how new science can affect the social, ethical, and economic aspects of medical practice. I welcome you all.