How many times do we hear people complain that drugs don’t work for them? Have you heard of people who have suffered from medicine-related side effects? How about people who hate taking medication because they fear possible side effects?

In this advanced age of molecular medicine, scientists found that certain genes are associated with how humans respond to drugs. Some genes are predictive of drug response. For instance, variations resulting in the deactivation of the gene VKORC1 can make one prone to bleeding because vitamin K activation is prevented. Another example is the loss of the effectiveness of clopidogrel, an anticoagulant commonly used for the prevention of heart attack, with variations in the activating enzyme encoded by CYP2C19.

One of the most promising genes that can be used for drug testing is CYP2D6, which encodes for a liver protein that is involved in the metabolism of about 25 percent of all know human medications. Changes in the gene may result in people taking more time, or becoming faster in eliminating drugs from their body. Slow elimination may result in a patient becoming prone to side effects, whereas rapid elimination may result in the need of a higher dose of the drug or an alternative drug.

However, the use of a genetic testing for drug response requires that variations should be present in the Filipino population. Using microarray technology that generates high output, researchers from the University of the Philippines Manila studied the prevalence of CYP2D6 variations among Filipinos.

The research found at least 18 variants in Filipinos. Among these are variants that are previously strongly linked to low-dose aspirin-induced gastrointestinal bleeding. This is important because aspirin is widely prescribed for patients with cardiovascular disease and for those with diabetes. Some bleeding may result in clinically important anemia that may result in weakness, blood transfusion or, in worst cases, death.

Other variants that are interesting include those linked with cancer and Timolol – showing of heart rate. No variant is associated with lung cancer.

Researchers hope that the findings of the study would set the stage for personalized treatment in the future. Who knows? Only time will tell when someone would CYP2D6 test to preemp gastrointestinal bleed. Hopefully, it will happen sooner than later.

Written by: 
Dr. Eva Cutiongco Dela Paz and Mr. Roemel Luna
University of the Philippines Manila

Published by:Department of Science and Technology-Science and Technology Information Institute (DOST-STII)