Potential Drug Interactions with Quercetin

Given quercetin’s potent effects, it may enhance or interfere with certain prescribed medications and treatments, such as:

• Blood thinners.¹⁷
• Chemotherapy agents doxorubicin and cisplatin.¹⁷
• Corticosteroids.¹⁷
• Liver-Metabolized Drugs—may increase the effects and side effects of cyclosporine and other drugs processed in the liver by slowing down the metabolic process.^17-19
• Quinolone antibiotics—may reduce the efficacy of these types of antibiotics, also known as fluoroquinolones.^4,10

By inhibiting actions of the protein in cell membranes responsible for transporting a number of different drugs (e.g., Cardizem®, Zantac™, Allegra®, and Lanoxin™), quercetin may increase the absorption and the risk of side effects.¹⁹