African genes in addiction treatment – buprenorphine
Addiction treatment is one of the exciting new applications of genetic testing in the field of pharmacogenetics.
In addiction treatment, the speed at which one metabolizes a drug can mean the difference between an effective treatment and a toxic one. It turns out that metabolism of a drug (pharmacokinetics) – that is, the time it takes to absorb, use, and eliminate a drug – is highly individual. It depends quite a bit on the enzymes in the liver, and those enzymes are determined by genetics.
“The vast majority of medications are metabolized by a group of enzymes called the Cytochrome P450 (CYP450) enzymes,” says Joseph Olechowski, the pharmacogenetic scientist in R & D at Addiction Labs. “We study seven genes that control the production of the CYP450 enzymes.”
In treating opioid addictions, buprenorphine is an attractive medication for reducing withdrawal symptoms. Olechowski sees African ancestry play a significant role when prescribing buprenorphine. Because it has a complex profile of interaction, precise metabolic information is key to an effective buprenorphine prescription. Genetic testing can be invaluable – and variants related to African genetics can make a big difference.
Dr. Wetsman says that the same African mutation in his liver enzyme, if found in a patient, could make all the difference in how someone might prescribe buprenorphine in treating the patient for opioid addiction.
“I have the 3A4 mutation. If you have this mutation and someone gives you buprenorphine, you metabolize it faster. In the case of buprenorphine, metabolizing degrades it, reducing its effectiveness.”
Such a patient is an example of someone who might benefit from a higher-than-average buprenorphine dosage.
Historically, according to Wetsman, when African-American patients reported the ineffectiveness of buprenorphine and requested larger doses, doctors misinterpreted the feedback.