St John's Wort and Clopidogrel

Q: 54 years old Asian male, recently discharged from the hospital after cardiac intervention due to an acute myocardial infarction, and on Dual Antiplatelet Therapy (DAPT), presented with severe upper GI bleed. Patient reports depressive mental health issue after his 'heart attack', and starts taking herbal medicines to feel better. Which widely used non-prescription drug should be suspected?

Answer: St. John's wort

The botanical name of St. John's Wort is Hypericum Perforatum. It is one of the most widely used herbal antidepressants worldwide. In the United States, an estimated 4.4 million adults are using it. It is particularly very popular in Eastern and Asian cultures. Frequently, its use goes unreported. 

St. John's wort increases the activity of clopidogrel by inducing CYP P450 enzymes, and can put patients at higher risk of bleeding. The objective of this question is to highlight patients' education on the risk of over-the-counter (OTC) and non-prescription herbal products when they are on life-saving drugs.

But here is the curveball: Some physicians use it in patients who are non-responders to clopidogrel to enhance its activity! The authors of this question would advise against such an adventure.

#pharmacology

#cardiology

References:

1. Monteiro MD, Dias ACP, Costa D, Almeida-Dias A, Criado MB. Hypericum perforatum and Its Potential Antiplatelet Effect. Healthcare (Basel). 2022 Sep 15;10(9):1774. doi: 10.3390/healthcare10091774. PMID: 36141386; PMCID: PMC9498564.

2. Trana C, Toth G, Wijns W, Barbato E. St. John's Wort in patients non-responders to clopidogrel undergoing percutaneous coronary intervention: a single-center randomized open-label trial (St. John's Trial). J Cardiovasc Transl Res. 2013 Jun;6(3):411-4. doi: 10.1007/s12265-013-9455-2. Epub 2013 Mar 6. PMID: 23463297.

3. Lau WC, Welch TD, Shields T, Rubenfire M, Tantry US, Gurbel PA. The effect of St John's Wort on the pharmacodynamic response of clopidogrel in hyporesponsive volunteers and patients: increased platelet inhibition by enhancement of CYP3A4 metabolic activity. J Cardiovasc Pharmacol. 2011 Jan;57(1):86-93. doi: 10.1097/FJC.0b013e3181ffe8d0. PMID: 20980920.

Trivia: St. John's wort plant is named after John the Baptist. The plant blooms around the feast of St. John the Baptist in late June.