Curriculum
Module 10 · 75 min

Herbals & Botanicals — Curcumin, St John's Wort, Ashwagandha

Where botanicals have real RCT evidence — and real drug interactions.

CoreClinicalAdvanced
Core topics

Lessons in this module

Learning objectives

By the end of this module you will be able to

Lesson summary ↓Graded claims ↓Self-check ↓Vignettes ↓Glossary ↓
  • L01
    List five clinically important drug interactions with St John's Wort (SSRIs, warfarin, OCPs, TKIs, transplant immunosuppressants).
  • L02
    Counsel patients about curcumin hepatotoxicity case reports and bioavailability enhancers.
  • L03
    Identify pregnancy and thyroid contraindications for ashwagandha.
  • L04
    Apply identity-testing standards (USP, AHP) to a botanical purchase.
Expected takeaways

What you should walk away believing

  • →St John's Wort is a strong CYP3A4 inducer — among the most dangerous supplement-drug interaction sources.
  • →Curcumin with piperine or phospholipid carriers achieves drug-level interactions; reports of DILI.
  • →Ashwagandha has modest anxiolytic RCT support but is contraindicated in pregnancy and may suppress TSH.
  • →Botanical identity is a real problem — DNA-barcoding studies repeatedly find substitutions.
Lesson · Core emphasis

What this means for you

Patient summary

Some herbs do something. St John's Wort can lower depression but can also make many medications stop working. Turmeric/curcumin has been linked to liver inflammation in some people. Pregnant or trying-to-conceive patients should avoid ashwagandha.

Clinician summary

Always screen the med list for St John's Wort (and induce a reconciliation conversation). Caution curcumin in patients on warfarin, statins (myopathy), or with elevated baseline LFTs. Avoid ashwagandha in pregnancy, thyroid disorders, and autoimmune disease (theoretical immunostimulation).

Advanced note

St John's Wort hyperforin content drives PXR-mediated CYP3A4 and P-gp induction; effect persists 2 weeks post-discontinuation. Curcumin's principal PK problem is rapid glucuronidation — bioenhanced formulations (Meriva phytosome, BCM-95 with piperine, Theracurmin nano) raise plasma exposure 20–100×; DILI cases (LiverTox category C) cluster in these formulations. Ashwagandha hepatotoxicity is under enhanced pharmacovigilance after Australian TGA's 2023 safety review; baseline LFTs reasonable with concomitant statins or acetaminophen. Berberine activates AMPK and inhibits PCSK9; lowers fasting glucose ~0.5–1% and LDL ~20–25 mg/dL but inhibits CYP3A4, 2D6, 2C9 with meaningful interactions for statins, calcineurin inhibitors, and DOACs.

Evidence framework

Where this module sits on the device evidence map

Botanicals: a few specific actives have RCT support; pharmacology and adulteration risks dominate clinical relevance.

Tier map →Tier 2 →Tier 3 →Tier 4 →
Myth-buster

Herbs are gentler than drugs.

Reality

Pharmacologically active herbs are drugs — with the same interaction potential and sometimes less consistent dosing.

Evidence-graded claims

What the data says

B
St John's Wort has RCT evidence for mild-moderate depression
Comparable to SSRI in some trials.
A
St John's Wort induces CYP3A4 and P-gp clinically
Extensively documented.
B
Curcumin with enhanced bioavailability formulations has caused DILI
LiverTox case series.
F
Ashwagandha is safe in pregnancy
Animal teratogenicity, contraindicated.
Objective self-check

Test the learning objectives

Score0 / 1(0 answered)
Q1L01 — Most dangerous SJW interaction?
Case vignettes

Apply it: real-world counseling scenarios

Short patient encounters that test your judgment, not your recall. Pick the most defensible response, then reveal the rationale and a sample coaching script you could actually say at the bedside.

Vignette proficiency
In progress · 0/1 submitted
Correct0/1 (0%)Pitfalls avoided0/0 (0%)Composite0
Composite weighting
Accuracy 60%Pitfalls 40%
← all pitfallsbalancedall accuracy →
Composite = 60% answer accuracy + 40% pitfalls avoided. Your weighting is saved for this module.
Order · randomized[1]
Vignette 1 of 1· source #1

Transplant patient on St John's Wort

Objective · Recognize CYP3A4 induction risk.

A renal transplant recipient on tacrolimus started St John's Wort for low mood. Tacrolimus level now subtherapeutic.

Most urgent step?
Quick check

Test yourself

Q1St John's Wort interacts with all EXCEPT:
Q2Ashwagandha contraindication?
Flashcards · Spaced repetition

Lock it in — review what's due

Due2Total2
FrontNew
2 in queue
St John's Wort mechanism of drug interaction?
Click to reveal answer
Glossary

Key terms & abbreviations

PXR
Pregnane X Receptor — nuclear receptor that upregulates CYP3A4 and P-gp; activated by hyperforin.
DILI
Drug-Induced Liver Injury — bin for hepatotoxic supplement reactions.
Further reading

Optional deeper dive

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Probiotics & the Gut — Strain-Specific Reality
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Performance & Cognition — Creatine, Caffeine, Nootropics