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Author: Admin | 2025-04-28
US Pharm. 2007;32(3)93-98.Perhaps the most common question patients ask about their medication, aside from "Why does this medication cost so much?" is, "Should I take this with or without food?" In most cases, upon looking in the package insert or drug information resource, the pharmacist discovers that most drugs in question may be administered without regard to meals. However, some food products are fortified with vitamins and/or minerals that can interact with certain drugs. Therefore, the more appropriate question to ask is, "Which foods should I avoid taking with my medications?" Furthermore, many patients consume mega-vitamins and supplements with known drug interactions, yet they are often unaware of these interactions. The purpose of this article is to equip pharmacists with a better understanding of drug–food interactions. This article differs from traditional reviews on this topic because the food substance is categorized individually, with the interacting drugs discussed under each heading. While there are hundreds of drug–nutrient interactions reported in the literature, the aim here is to focus on those that are more common and clinically significant.Grapefruit JuiceOne of the most well known food–drug interactions is grapefruit juice and the HMG-CoA reductase inhibitors, more commonly known as statins. Grapefruit juice, in large quantities (32 oz. or more per day), can inhibit the cytochrome P450 3A4 (CYP3A4) enzyme and increase blood levels of drugs metabolized by this pathway, such as certain statin drugs.1,2 Note that this interaction applies to grapefruit juice, not the whole fruit itself. Furthermore, not all statins exhibit this interaction: Only atorvastatin (Lipitor), simvastatin (Zocor), and lovastatin (Mevacor) are metabolized by the CYP3A4 isoform. Of these three statins, atorvastatin is least affected by grapefruit juice. Thus, the other statins, namely rosuvastatin (Crestor), pravastatin (Pravachol), and fluvastatin (Lescol), may be acceptable alternatives for patients who regularly consume large amounts of grapefruit juice.3 Underlying this interaction is the ability of some constituents of grapefruit juice to inhibit CYP3A4 in the intestine, thereby reducing the metabolism of the statins and increasing the drug's bioavailability. Thus, when large amounts of grapefruit juice are consumed in combination with these drugs, patients are at an
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