Which over-the-counter item is contraindicated for patients taking ranolazine?

Ranolazine is a medication primarily used for treating chronic angina. It works by altering the way the heart uses energy and can improve blood flow, thus helping angina patients. One of the concerns when patients are undergoing treatment with ranolazine is the potential interaction with other substances that can affect how the drug is metabolized.

St. John's Wort is a herbal supplement that is known to induce certain enzymes in the liver, particularly CYP3A4, which play a significant role in the metabolism of various drugs, including ranolazine. When these enzymes are induced, the effectiveness of ranolazine can be reduced, potentially leading to worsened angina symptoms since the drug may not work as intended. Thus, patients taking ranolazine should avoid St. John's Wort to ensure that the medication can exert its full therapeutic effect.

In contrast, Vitamin C, aspirin, and ibuprofen do not have documented interactions or contraindications with ranolazine in the same substantial way that St. John's Wort does. While they might have their own side effects or interactions in different contexts, they do not significantly impact the metabolism of ranolazine in a manner that would compromise its efficacy or safety. Therefore, St. John's Wort stands out as a contraindicated item