Warfarin, which is used to prevent blood clots after a heart attack, stroke or major surgery, is one of the world’s most widely prescribed drugs. But it’s also notoriously difficult to find the correct dose. An international research team, including pharmacist Minoli Perera from UChicago, recently found a genetic variation that could help estimate the correct dose for African Americans.
In the first genome-wide association study to focus on warfarin dose requirement in African-Americans, Perera and her colleagues from a consortium of 42 researchers from 17 institutions around the world found that people of African ancestry who carry this variant — more than 40 percent of the patients enrolled in this study — need significantly less warfarin to obtain optimal benefits compared to those who lack this variant.
“It’s very important to get warfarin dosing right,” said the study’s lead author, Minoli Perera, PharmD, PhD, assistant professor of medicine at the University of Chicago. “People take this drug because they’ve had a clotting problem. If you give them too little, they could form another clot, possibly causing a stroke or pulmonary embolism. If you give too much, they could bleed.”
But dose requirements vary widely, making it difficult to get the quantity right. “Some people need a few milligrams per day and some need 20,” Perera said. The average dose for African-Americans generally has been about 30 percent higher than that for Caucasians.
Video provided by University of Florida Health.
Perera, M., Cavallari, L., Limdi, N., Gamazon, E., Konkashbaev, A., Daneshjou, R., Pluzhnikov, A., Crawford, D., Wang, J., Liu, N., Tatonetti, N., Bourgeois, S., Takahashi, H., Bradford, Y., Burkley, B., Desnick, R., Halperin, J., Khalifa, S., Langaee, T., Lubitz, S., Nutescu, E., Oetjens, M., Shahin, M., Patel, S., Sagreiya, H., Tector, M., Weck, K., Rieder, M., Scott, S., Wu, A., Burmester, J., Wadelius, M., Deloukas, P., Wagner, M., Mushiroda, T., Kubo, M., Roden, D., Cox, N., Altman, R., Klein, T., Nakamura, Y., & Johnson, J. (2013). Genetic variants associated with warfarin dose in African-American individuals: a genome-wide association study The Lancet DOI: 10.1016/S0140-6736(13)60681-9