RH Herb-Drug Interaction Pharmacology 3

Question 1

Which mechanism best describes a pharmacodynamic herb-drug interaction?

Accepted Answer

Herb and drug produce additive or opposing effects at the same physiological target

Answer

Pharmacodynamic interactions occur when herb and drug act on the same receptor, pathway, or physiological system, producing additive, synergistic, or antagonistic effects.

Question 2

A patient on SSRIs for depression also begins taking high-dose St. John's Wort. The most serious potential pharmacodynamic concern is:

Accepted Answer

Serotonin syndrome due to combined serotonergic activity

Answer

St. John's Wort inhibits serotonin reuptake; combined with SSRIs, excess serotonergic activity can trigger life-threatening serotonin syndrome.

Question 3

Valerian and kava taken alongside benzodiazepines may cause excessive sedation. This is an example of:

Accepted Answer

Synergistic pharmacodynamic CNS depression

Answer

Valerian and kava both potentiate GABA activity, producing additive CNS depression when combined with benzodiazepines.

Question 4

Which herb most commonly interacts with antiplatelet drugs (e.g., aspirin, clopidogrel) via pharmacodynamic addition?

Accepted Answer

Ginger

Answer

Ginger contains gingerols that inhibit thromboxane synthesis and platelet aggregation, adding to antiplatelet drug effects and increasing bleeding risk.

Question 5

A patient on metformin for type 2 diabetes begins using berberine-containing herbs. The primary concern is:

Accepted Answer

Additive blood glucose lowering causing hypoglycemia

Answer

Berberine independently lowers blood glucose via AMPK activation and gut flora modulation, creating additive hypoglycemic risk with metformin.

(RH) Registered Herbalist Practice Test

(RH) Registered Herbalist Practice Test

RH Herb-Drug Interaction Pharmacology 3