Genetic Differences In Minorities May Cause Varied Reactions To Medicines.

Genetic differences among minorities may explain why some medicines are more effective in some patients than others, a new study finds. The study advises physicians and managed care plans to be aware of the need to tailor drug regimens for individuals considering their ethnic or racial group, and to be on alert for uncommon responses or side effects from medicines used by minority patients.

The study, to be published as a supplement to the October Journal of the National Medical Association, shows that responses to medications among minority patients can vary based on genetic, cultural and environmental factors. The researchers advise that such factors must be considered by health plans and providers in order to ensure access by minority patients to clinically appropriate prescription drugs and to prevent further widening of disparities in the healthcare that minority populations receive.

“A ‘one-drug-fits-all’ approach to therapy does not take into account individual patient responses to medicines,” said L. Natalie Carroll, M.D., president of the National Medical Association. “New science is helping to identify differences in the ways individuals react to drug therapy. Any attempt to control spending should take such differences into account.”

The study, Racial and Ethnic Differences in Response to Medicines: Towards Individualized Treatment, was co-authored by the National Medical Association (NMA) and the National Pharmaceutical Council (NPC). It shows that genetic variations can affect how the body processes a drug and its overall effect on the body, and that certain genetic variations are more prevalent among specific population groups. Although race and ethnicity are imprecise indicators of genetic differences, they can be helpful in anticipating variations in response to a medicine. For example:

* There are general differences in the underlying characteristics of high blood pressure for black and Caucasian patients. For instance, because black patients tend to retain more salt and have a higher incidence of salt-sensitive high blood pressure, diuretics used in combination with other blood pressure medications may be necessary to achieve targeted blood pressure levels among black patients.

* Medicines used to treat pain, such as codeine, have been shown to affect Caucasians and East Asians differently. Because many East Asians metabolize codeine differently than Caucasians, East Asians often require higher dosages for effective pain relief.

* Ashkenazi Jews are significantly more susceptible to a potentially life-threatening blood disorder that can develop as a result of therapy with the drug clozapine used to treat schizophrenia. The specific set of genes thought to be associated with this disorder is found in 10 to 12 percent of the Jewish population in Israel and the U.S., but in less than one percent of the total Caucasian population of the U.S.

In addition to genetic factors, cultural factors (such as attitudes towards medicines, health beliefs, and family influence) common to members of different ethnic groups, and environmental factors (such as pollutants, smoking and climate) can affect how patients respond to drugs and compliance with prescribed treatments.

Varying cultural beliefs lead to actions that may increase health risk; for example, self-treatment with herbal and folk remedies may not effectively treat the disease or may interact with other treatments. Communication barriers are also common obstacles to optimum care.

“Multiple factors affect a patient’s response to a given drug and thus the effectiveness of therapy,” said Dr. Carroll. “Physicians, who work in a clinical setting, know this. Problems can arise if clinical decisions, which must be based on the individual’s specific health needs, are constrained by techniques designed to control costs.”

The authors make several recommendations:

* Patients from diverse racial and ethnic groups must receive care tailored to their specific needs so that disparities in health care do not become even greater than those identified by the IOM report.

* Health plans should not restrict access to specific drugs based on cost alone or impose drug preferences that preclude individual patients from accessing medicines that are safe and effective for them.

* When treating minority patients, physicians and other health care providers must be mindful of uncommon responses or unexpected side effects from medicines. Dosage adjustments may also be necessary.

* Efforts to include greater numbers of diverse populations in clinical trials and outcomes studies should be strongly encouraged in order to further understand the clinical implications of drug therapies among racial and ethnic groups.

* Health care providers should stay abreast of developments in pharmacogenomics, the growing field that studies the genetic basis of differences in patients’ response to drugs. Such studies will increasingly enable physicians to customize care for patients and should be used by health plans to refine strategies that manage drug spending.

The full study can be found at http://www.npcnow.org