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Since the manual doesn’t list the specific herbs, we have to rely on the standard “hit list” that usually appears in pharmacy exams. Here is the cheat sheet of the most clinically significant interactions you need to memorize for the Herbal Pharmacotherapy section:
Use: Depression.
The Problem: It is a potent Inducer of CYP450 enzymes (specifically CYP3A4).
The Interaction: It lowers the concentration of many critical drugs, leading to treatment failure.
Exam Examples:
Contraceptives: Risk of unintended pregnancy.
Warfarin: Risk of clotting (low INR).
Digoxin: Reduced heart control.
Antiretrovirals (HIV): Risk of viral resistance.
If the question involves a patient on Warfarin, Aspirin, or Clopidogrel, watch out for these herbs. They promote bleeding.
Ginkgo Biloba: Used for memory/dementia. It has anti-platelet effects.
Garlic: Used for cholesterol/BP. High doses increase bleeding time.
Ginseng: Used for energy. Can decrease the effect of Warfarin (lowers INR) but also has variable effects on bleeding.
The Syllabus Link: The manual specifically asks for “Interactions with food”4.
The Problem: It is a potent Inhibitor of CYP3A4 (in the gut wall).
The Interaction: It increases the levels of drugs, leading to toxicity.
Key Drugs to Avoid:
Statins (Atorvastatin/Simvastatin) $\rightarrow$ Risk of Rhabdomyolysis (muscle breakdown).
Calcium Channel Blockers (Nifedipine/Amlodipine) $\rightarrow$ Risk of hypotension/flushing.
Exam Tip: If you see a question about a patient whose BP medication or HIV drugs “suddenly stopped working,” look for St. John’s Wort in the options!
