When you sit down to enjoy a beverage, do you think about whether it might affect the medications you take? Years ago, research on grapefruit juice showed that what you drink can indeed affect your pills. Coffee may also interact with some drugs. To begin with, it reduces absorption of levothyroxine. What’s more, fluoroquinolones such as ciprofloxacin or levofloxacin increase the effects of caffeine in the body. What about a beverage that is supposed to be extremely healthful? Does green tea interact with prescription medicines?

How Does Green Tea Interact with Medications?

Q. After reading about green tea having a positive effect on vision, I wondered if there were any adverse interactions between green tea and prescription drugs. I take several heart drugs since having stents placed in 2012.

My Google search found an article suggesting it might interact with drugs. I’ve recently started drinking green tea, but I’m worried that it could interact with the beta blocker metoprolol I need to take. Should I not drink green tea at all?

A. We have seen only a few studies of the effects of green tea on vision. However, it seems that the polyphenol compounds in green tea can help protect retinal nerve cells (Pakistan Journal of Pharmaceutical Sciences, Nov. 2015). 

Could Green Tea Interact with Metoprolol?

Luckily, green tea and its active ingredient, epigallocatechin-3-gallate (EGCG), do not appear to interact with metoprolol (European Journal of Heart Failure, May, 2008). Green tea does have other interesting interactions, however. It can lower concentrations of the beta blocker blood pressure drug nadolol (European Journal of Clinical Pharmacology, June 2018). This could make the drug less effective.

In addition, green tea compounds might affect blood levels of the cholesterol-lowering drugs simvastatin and rosuvastatin (Journal of Food and Drug Analysis, April 2018). Recent research suggests that EGCG and other polyphenols may affect the microbiome of the digestive tract (Critical Reviews in Food Science and Nutrition, Aug. 26, 2019).

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