Cultural Considerations in Ethnopharmacology: Impact on Drug Responses

1. Ethnopharmacology by Sue Henderson

2. Ethnopharmacology • Study of the effect of ethnicity on responses to prescribed medication and incorporates pharmacogenetics, the study of genetic variations in responses to drugs.

3. Ethnicity: Shared cultural bonds, common genetic heritage or both Race Common lineage and geographic origin of ancestry (genetics) Culture Common learned beliefs and customs

4. Effects of ethnicity on drug response • Pharmacokinetics (drugs absorption, metabolism, distribution, and elimination) • Pharmacodynamics (drugs mechanism of action and effects at the target site) • Consumer adherence and education • Wide variation in drug response within each ethnic group

5. Cultural competence involves: • Working within the consumers cultural context Knowledge of consumers: • Beliefs/values about health/illness • Responses to treatment, including drug therapies.

6. Assessment • “What do you think caused your health problem?” • “What treatment do you think will help you?”

7. Metabolism of drugs • Most drugs metabolized by liver enzymes. • Cytochrome P-450 (CYP) is a common group of liver enzymes • Rate of metabolism will affect drug blood levels • Genetic abnormalities in enzymes common • Enzymes vary by race/ethnic group

8. Genetic abnormalities Ultrarapid metabolizers • > 2 functional copies of CYP2D6 gene faster than normal enzyme activity = lower levels of drug in blood Poor metabolizers • 2 non-functional copies of CYP2D6 gene slower than normal enzyme activity = higher level of drug in blood

9. Asians: Antipsychotics Asians same dose as whites: • Higher blood levels of typical antipsychotics • Have more EPSE • Need lower doses (Atypicals may be better but few ethno-pharmacologic studies on atypicals)

10. Tricyclic antidepressants Asians compared whites have: • Faster therapeutic response • Higher blood levels drug • More adverse effects (such as delirium) • Adverse effects occur at much lower dosages. (Few ethno-pharmacologic studies on SSRIs)

11. Non White: Lithium • Require lower doses • Report more lethargy and dizziness (even when blood levels similar). • Monitor closely for symptoms of toxicity (blood levels may be higher than in white’s given same dosage).

12. Cultural/Lifestyle • Tobacco/alcohol use (influenced by cultural & genetic factors) affect drug response. • Tobacco/alcohol increase or decrease rate of drug metabolizm & drug clearance. • Smoking decreases blood levels of typical antipsychotics (? caused by effects of smoking on liver enzymes).

13. Adherence • Adverse effects contribute to non-adherence. • Drug effects may be interpreted as negative or positive depending on the consumers beliefs/expectations. Factors affecting drug adherence: • Language barriers • Clinicians’ beliefs/preconceptions • Consumers distrust of the health care system

14. References Muñoz, C., & Hilgenberg, C. (2005). Ethnopharmacology American Journal of Nursing, 105(8), 40 - 48.