Ethnopsychopharmacology

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Ethnopsychopharmacology - Ethnic Drug Vibes

  • Studies ethnic variations in drug response & metabolism.
  • Key Factors: Genetic (e.g., CYP450 enzymes), environmental, cultural beliefs, diet.
  • Impacts: Drug efficacy, side effects, optimal dosage.
    • E.g., Asians may require ↓ doses of some antipsychotics (e.g., risperidone) due to slower metabolism (CYP2D6 variants).
  • Considers cultural views on illness & treatment acceptance.

⭐ Certain ethnic groups (e.g., some East Asians) show higher rates of Stevens-Johnson syndrome with carbamazepine due to HLA-B*1502 allele presence. Test before prescribing!

Pharmacokinetics (PK) - Ethnic Drug Routes

  • Ethnic variations significantly alter drug ADME (Absorption, Distribution, Metabolism, Excretion).
  • Metabolism: Cytochrome P450 (CYP) enzyme polymorphisms are key drivers.
    • CYP2D6: Metabolizes many antidepressants (e.g., TCAs, SSRIs) & antipsychotics (e.g., risperidone).
      • Indian populations show diverse frequencies of poor (PM), intermediate (IM), extensive (EM), and ultra-rapid (UM) metabolizer phenotypes.
      • Alters drug efficacy and risk of adverse drug reactions.
    • CYP2C19: Affects diazepam, clomipramine, citalopram. Higher PM prevalence in some Asian populations, including Indian groups.
    • CYP2C9: Important for warfarin, phenytoin metabolism.
  • Absorption: Genetic variations in drug transporters (e.g., P-glycoprotein encoded by ABCB1 gene).
  • Distribution: Differences in body composition (fat vs. muscle), plasma protein binding. Drug Metabolism and Detoxification Pathway ⭐ > CYP2D6 polymorphism is a major determinant of response and tolerability to risperidone; Indian populations exhibit considerable allelic diversity, impacting optimal dosing strategies for schizophrenia treatment.

Pharmacodynamics (PD) - Ethnic Drug Targets

  • Genetic variations in drug targets (receptors, transporters) cause differing drug effects across ethnicities.
  • Examples:
    • SERT (SLC6A4) (5-HTTLPR): Impacts SSRI response (S-allele vs. L-allele).
    • DRD2 (Taq1A): Affects antipsychotic efficacy & Tardive Dyskinesia risk (A1 allele).
    • COMT (Val158Met): Influences dopamine breakdown, affecting drug response.
    • BDNF (Val66Met): May modify antidepressant outcomes.
  • Result: Varied efficacy & side effect profiles.

⭐ The DRD2 Taq1A A1 allele, linked to ↓ D2 receptor density, often predicts poorer response to typical antipsychotics.

Genetic Polymorphisms - DNA Drug Codes

  • Genetic variations alter drug pharmacokinetics (PK) & pharmacodynamics (PD).
  • Cytochrome P450 (CYP) Enzymes:
    • CYP2D6: Metabolizes many antidepressants (TCAs, SSRIs), antipsychotics (risperidone).
      • Phenotypes: Ultrarapid (UM), Extensive (EM), Intermediate (IM), Poor (PM).
      • UMs: ↑ metabolism → therapeutic failure. PMs: ↓ metabolism → toxicity.
    • CYP2C19: Metabolizes diazepam, clomipramine. Higher PM prevalence in Asians.
  • HLA Alleles & Hypersensitivity:
    • HLA-B*1502: Strong link to carbamazepine-induced SJS/TEN.
    • HLA-A*3101: Carbamazepine hypersensitivity.
  • Impact: Guides drug selection & dosing for personalized therapy.

Pharmacogenomic tests by number of genes and specific genes

⭐ HLA-B*1502 testing is crucial before carbamazepine in at-risk populations (e.g., Asian ancestry) to prevent SJS/TEN.

Cultural Factors & Clinical Pearls - Mind Over Meds

  • Diet & Herbs: Turmeric (CYP3A4 inducer), grapefruit (inhibitor) alter drug levels. Inquire about traditional remedies (e.g., Ashwagandha) for interactions.
  • Beliefs & Stigma: Influence illness perception, help-seeking, and medication adherence. Address with sensitivity.
  • Genetic Variations: CYP2D6, CYP2C19 polymorphisms common; may require dose adjustments (↑ or ↓).
  • Clinical Pearls: Start low, go slow. Psychoeducation is vital. Culturally sensitive family involvement.

⭐ CYP2D6 polymorphisms, prevalent in Indian populations, significantly impact metabolism of many TCAs, SSRIs, and risperidone, often necessitating dose adjustments.

High‑Yield Points - ⚡ Biggest Takeaways

  • Genetic polymorphisms (e.g., CYP2D6, CYP2C19) alter psychotropic metabolism across ethnicities.
  • Some Indian populations show slower metabolism of TCAs & SSRIs, needing dose ↓.
  • Dietary habits (e.g., turmeric) can cause drug interactions.
  • Cultural views affect medication adherence and side effect reporting.
  • Therapeutic Drug Monitoring (TDM) is key with suspected ethnic variations.
  • ADR profiles may differ; e.g., ↑ risk of antipsychotic-induced metabolic syndrome in some groups.
  • Always consider ethnicity for dose individualization.

Practice Questions: Ethnopsychopharmacology

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Flashcards: Ethnopsychopharmacology

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In _____, the affected male person has the belief that his penis is shrinking and may disappear into his abdominal wall and he may then die

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In _____, the affected male person has the belief that his penis is shrinking and may disappear into his abdominal wall and he may then die

Koro (culture-bound syndrome)

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