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Using Your Genes to Personalize Prescriptions


For many organ transplant recipients, staying healthy can be a delicate dance.

They rely on a drug called tacrolimus to tame the immune system and prevent it from rejecting a donated organ. The amount of the drug needed to protect the organ differs from person to person.

Here’s the challenge: Tacrolimus has what doctors call a narrow therapeutic window. Too little, and the organ can be rejected; too much can cause serious side effects, including diabetes and skin cancer. 

A few years ago, Vanderbilt Health doctor and researcher Kelly Birdwell discovered that a single gene variation influences how much medicine a patient needs to prevent organ rejection.

Information about this gene and seven more known to affect drug response is available in PREDICT, an innovative program that helps Vanderbilt Health’s patients get the right drug at the right dose.

PREDICT stands for Pharmacogenomic Resource for Enhanced Decision-Making in Care and Treatment. Here are a few basics about how PREDICT is defining personalized care.

What is pharmacogenomics?

Pharmacogenomics is a relatively new area of science that studies how a person’s genes affect his or her response to drugs. The name comes from pharmacology, the science behind medication, and genomics, the study of genes and how they work. The Food and Drug Administration has included pharmacogenomic information in guidelines for prescribing at least 70 medications.

What’s the goal of PREDICT?

To provide information to doctors in a way that helps them prescribe drugs that work better and more safely. That’s better for patients and can help reduce healthcare costs.

How does PREDICT work?

A single blood sample is tested for multiple genes known to influence drug response. The information is available to doctors in a patient’s electronic medical record.

How many genes are tested?

Currently, PREDICT tests eight genes known to influence how drugs are absorbed, distributed, metabolized and excreted by the body. The most recently added gene can help make dosage decisions for about 25 percent of medications on the market.

What types of medications are covered by PREDICT?

In addition to tacrolimus, PREDICT can help with prescribing medications used to treat leukemia, autoimmune disorders, depression, psychosis, pain, blood clotting, hypertension, allergies, high cholesterol and more.

As new genetic variations that affect drug response are identified, additional genes will be added to the panel.

Where can I learn more about PREDICT?

The latest information about PREDICT can be found at

Does PREDICT test for genes that cause cancer?

PREDICT tests the genes you inherited from your parents, known as “germ-line DNA.” Cancer is typically caused by genetic changes in normal cells that transform them into malignant cells.

Vanderbilt-Ingram Cancer Center is a world leader in “precision medicine” for cancer, which uses information about genetic changes in tumor cells to target therapy. The center’s scientists have developed as a tool to help healthcare providers around the world make treatment decisions based on the latest genomic information available.