Nursing Field Notes / Pharmacology · Complementary & Alternative Agents
Herbal Supplements 🌿
Not "just vitamins" — they interact like drugs because many act like drugs
NG-230PHARMADHD-friendly visual edition
Herbal & dietary supplements are NOT regulated by the FDA the same way prescription drugs are — no proof of efficacy is required before sale. Patients often don't think of them as "medications" and don't report them unless specifically asked. Yet several of the most common ones cause serious, well-tested bleeding and serotonin interactions.
Induces CYP450 + serotonin syndrome risk — see next section
🧠 "SP treats the Swollen Prostate." Match the letters to the body part: SP → prostate, black co-HOT → hot flashes, hawthorn → heart.
🩸 The bleed-risk family
These raise bleeding risk, especially combined with anticoagulants/antiplatelets (warfarin, DOACs, aspirin, clopidogrel):
🌳Ginkgo Biloba
🧄Garlic
🫚Ginger
🧴Vitamin E
🐟Omega-3
🌱Ginseng
🧠 "The G's (mostly) bleed." Ginkgo, Garlic, Ginger, ginseng — plus Vitamin E and omega-3 — round out the bleed-risk crew.
⛽ Not FDA-regulated the same way
Supplements are regulated as food-category products, not drugs — manufacturers don't have to prove safety or efficacy before selling them. Potency and purity can vary between brands and even between bottles.
🧠 "Not tested like a drug ≠ not acting like a drug." Just because it's sold OTC in the supplement aisle doesn't mean it's inert.
⚠️
INTERACTIONS
STEP 2 · THE HIGH-YIELD DANGERS
St. John's Wort is the single most heavily tested herb — it both weakens drugs and can trigger serotonin syndrome.
☀️ St. John's Wort — induces CYP450
EXAM TIP St. John's Wort speeds up the liver's CYP450 enzymes, which clears many drugs faster than normal — so blood levels drop and the drug becomes less effective.
🧠 "St. John's Wort works against your other drugs." It doesn't just fail to help — it actively lowers the level of many drugs it's combined with, including birth control and warfarin. Reduced INR on a client taking both = St. John's Wort is the classic culprit.
🚨 St. John's Wort + antidepressants — serotonin syndrome
St. John's Wort has serotonergic activity of its own. Combined with SSRIs, MAOIs, or TCAs, serotonin can build to dangerous levels.
Never mix St. John's Wort with SSRIs, MAOIs, or TCAs — screen for it every time an antidepressant is on the med list.
🧠 "Sunshine herb, serotonin storm." St. John's Wort feels harmless because it's "natural" — but stacked serotonin from any source (herb + antidepressant) can kill.
🔪 Stop before surgery
Because so many supplements affect bleeding, sedation, or drug metabolism, the general teaching point is: stop most herbal supplements 2–3 weeks before a scheduled surgery, and always disclose supplement use during pre-op screening. Hawthorn is specifically flagged as a priority drug-drug interaction to review before any procedure.
🧠 "2 to 3, before they cut on me." Two to three weeks is the standard teaching window for stopping most herbal supplements pre-op.
🗣️
ALWAYS ASK
STEP 3 · THE NURSING PRIORITY
If you don't ask, they usually won't tell you — this is the single highest-yield nursing action on this whole page.
✅ Medication reconciliation must include herbs
1
🗣️ Ask specifically — "any vitamins, herbs, or supplements?" Don't assume they'll volunteer it
2
🩸 Screen for bleed-risk herbs if the patient is on any anticoagulant/antiplatelet
3
☀️ Screen for St. John's Wort if the patient is on an antidepressant, OCP, or warfarin-type drug
4
🔪 Ask about supplements at every pre-op assessment — plan to stop 2–3 weeks out
5
🍬 Watch glucose if glucosamine + anti-diabetic medications are both on the list
🧠 "Ask like it's a drug — because it acts like one." This is the single testable nursing action across this entire topic.
💊 One-glance interaction map
Client is on…
Ask about…
Warfarin / DOAC / aspirin
Ginkgo, garlic, ginger, vitamin E, omega-3, ginseng
SSRI / MAOI / TCA
St. John's Wort — serotonin syndrome risk
Oral contraceptives
St. John's Wort — reduced efficacy
Anti-diabetic medication
Glucosamine — hypoglycemia risk
Cardiac / antihypertensive meds
Hawthorn — priority drug-drug interaction
🧠 Big-picture mnemonic
"BLEED & BLOCK":
BLEED — ginkgo, garlic, ginger, vitamin E, omega-3, ginseng
BLOCK — St. John's Wort blocks other drugs from working by speeding their clearance
🧠 One family raises bleeding risk, the other lowers everything else's effectiveness — know which is which.
⚡
QUICK RECALL
SAY IT OUT LOUD
🗣️ Not FDA-regulatedpatients don't report it — always ask
🩸 Ginkgo/garlic/ginger/vit E↑ bleeding with anticoagulants
🔪 Stop 2–3 weeks pre-opdisclose at every pre-op screen
🎯 Cover & check — 4 rapid-fire questions
Q1: A client on warfarin also takes ginkgo biloba and garlic supplements. What's the concern?
Increased bleeding risk — ginkgo, garlic, ginger, vitamin E, omega-3, and ginseng all add to anticoagulant/antiplatelet bleeding risk.
Q2: How does St. John's Wort reduce the effectiveness of oral contraceptives and warfarin?
It induces liver CYP450 enzymes, which metabolizes those drugs faster — blood levels drop and efficacy is reduced (e.g., breakthrough bleeding on OCPs, falling INR on warfarin).
Q3: A client taking St. John's Wort and an SSRI develops shivering and diarrhea. What is this an early sign of?
Mild serotonin syndrome — stop the combination and notify the provider before it progresses to muscle rigidity, fever, seizures, or death.
Q4: Why must nurses specifically ask about herbal supplement use?
Supplements aren't FDA-regulated the same way as drugs, and patients often don't consider them "medications," so they frequently go unreported unless asked directly — especially important pre-op and when starting anticoagulants or antidepressants.