This post was written by Quyen Nguyen, PharmD, BCACP, Internal Medicine Residency Clinic.
Green tea dates back to the 8th century and remains a popular beverage due to its plethora of health benefits, including cancer-fighting and anti-inflammatory properties, as well as a reduced risk of cardiovascular and neurodegenerative diseases. However, because of its caffeine content and potential to interact with certain medications, some people should only drink this beverage in moderation.
Medications to avoid with green tea
When you start consuming green tea or taking a green tea supplement, consult your primary care provider and pharmacist. There are many drugs that interact with green tea to some degree. Consider avoiding this drink if you take the following medications:
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Statins (atorvastatin and rosuvastatin): Green tea may reduce the levels and benefits of statin drugs. It may also lead to an increase in unhealthy cholesterol.
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Beta blockers (nadolol): Green tea may reduce the effectiveness and benefits of these prescriptions. It may also lead to an increase in blood pressure.
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Warfarin: Green tea may affect how long it takes blood to clot, increasing the bleeding risk for patients taking this medication.
Interactions and side effects
Green tea can inhibit intestinal and hepatic (relating to the liver) drug transporters and drug-metabolizing enzymes, which may affect how the body absorbs, distributes, and breaks down medications. This could result in reduced drug exposure or bioavailability. It could also increase the risk of side effects.
Because this beverage also contains caffeine, when used in excess or in combination with certain medications, it can cause rapid heartbeat, anxiety and restlessness. This is especially relevant if used with other medications containing caffeine, such as caffeine Excedrin Migraine®, or with medications that contain stimulants such as Sudafed®.
While the caffeine content in green tea is generally lower than that of a cup of coffee, it can vary widely depending on the type of leaves used and how it's prepared. Always confirm the caffeine content of the specific product you are consuming and consider your total daily caffeine intake. Keep in mind, abrupt withdrawal from caffeine can cause headaches, fatigue, nausea, difficulty concentrating and irritability.
Sources:
Potential Role of Green Tea Catechins in Various Disease Therapies: Progress and Promise
Green Tea Catechins as Perpetrators of Drug Pharmacokinetic Interactions.
Update of Green Tea Interactions With Cardiovascular Drugs and Putative Mechanisms
Enzyme- and transporter-mediated beverage-drug interactions: An update on fruit juices and green tea