Related Experiment Video
Updated: Jul 20, 2026
07:51
High-throughput Identification of Synergistic Drug Combinations by the Overlap2 Method
Published on: May 21, 2018
Management of grapefruit-drug interactions
Amy L Stump1, Terri Mayo, Alan Blum
1University of Alabama School of Medicine, Tuscaloosa, Alabama, USA.
American Family Physician
|August 31, 2006
Summary
Grapefruit consumption can dangerously interact with certain medications by affecting their metabolism. Alternative fruits or medications can prevent adverse drug reactions and toxicity risks.
Area of Science:
- Pharmacology
- Clinical Nutrition
- Drug Metabolism
Background:
- Grapefruit is a nutritious fruit but can alter the metabolism of numerous medications.
- This interaction poses risks of drug toxicity and adverse effects.
- Oral medications metabolized by intestinal cytochrome P450 3A4, with low bioavailability and narrow therapeutic indices, are particularly susceptible.
Purpose of the Study:
- To inform healthcare providers and patients about the risks of grapefruit-medication interactions.
- To identify specific drug classes known to interact with grapefruit.
- To present safe alternatives for patients at risk of or experiencing these interactions.
Main Methods:
- Review of existing literature on grapefruit's effect on drug metabolism.
- Identification of medication characteristics associated with grapefruit interactions.
- Listing of common drug classes and their grapefruit-interactive properties.
Main Results:
- Grapefruit significantly impacts the metabolism of drugs like statins, antiarrhythmics, immunosuppressants, and calcium channel blockers.
- Medications extensively metabolized by CYP3A4, having low bioavailability and narrow therapeutic indices, are prone to interaction.
- Effective alternative medications exist for these drug classes.
Conclusions:
- Patients on interacting medications should consider avoiding grapefruit or substituting alternative drugs.
- Dietary modifications, such as choosing other citrus fruits, can mitigate interaction risks.
- Awareness of grapefruit-drug interactions is crucial for patient safety and effective pharmacotherapy.
Related Concept Videos
01:26Pharmacokinetics: Drug–Food and Drug–Viral Interactions
A drug interaction occurs when the concurrent use of another drug, food, or an external substance alters the pharmacological activity of a drug. This interaction can modify the action of the original drug, affecting its effectiveness and safety.Drug–food interactions are significant as they impact drug absorption, metabolism, and excretion. For example, grapefruit juice is a well-known disruptor of drug metabolism. It inhibits the cytochrome P450 3A4 enzyme, crucial for the metabolism of many...
01:30Drug toxicity: Drug–Drug Interaction
Drug–drug interactions can precipitate toxicity through multiple mechanisms. Absorption interactions alter how drugs enter the body, exemplified when ranitidine increases the absorption of basic drugs, while cholestyramine decreases the levels of propranolol. Protein binding interactions occur when drugs share the same binding sites on plasma proteins. Drugs like aspirin and warfarin, when bound in excess, can lead to increased free drug concentrations, enhancing the potential for...
01:25Pharmacokinetics: Drug–Drug Interactions
Drug interactions occur when the pharmacological effect of one drug is altered by another substance, either enhancing or diminishing its activity. The drug whose activity is altered is known as the object drug, and the substance causing the alteration is called the agent drug or the precipitant. The net effects of these interactions are mostly undesirable, leading to decreased effectiveness or increased adverse effects. In rare cases, interactions can be beneficial, such as the enhanced...
01:23Factors Affecting Protein-Drug Binding: Drug Interactions
Drug interactions are a critical aspect of pharmacology and can occur when two or more drugs compete for the same binding site. This competition can result in one drug displacing another, altering the effect of the displaced drug. Drug interactions are complex processes that rely heavily on how much of the displacer drug is present and how strongly it can bind to the same sites as the displaced drug.
Displacement interactions can have varying outcomes, ranging from toxicity to virtually...
Displacement interactions can have varying outcomes, ranging from toxicity to virtually...
01:08Effect of Hepatic Disease on Pharmacokinetics: Dose Adjustments Due to Hepatic Impairment
Hepatic impairment, characterized by decreased liver function, does not uniformly mandate adjustments in drug dosage. Whether dosage modifications are necessary depends on various factors related to the drug's metabolism and elimination pathways. If a drug is primarily excreted via the kidneys and bypasses significant hepatic processing, if it undergoes minimal metabolic transformation in the liver, or if it is volatile and primarily expelled through the lungs, dose adjustments may not be...
01:29Drug-Receptor Interactions
Drug-receptor interaction describes the binding of receptors by drugs, but not all drug-receptor interactions result in activation and tissue response. For instance, the binding of agonists activates the receptor to generate a cellular reaction, while antagonists bind to receptors without causing their activation.
Several parameters, such as the drug's affinity for its receptor and its efficacy, which is its ability to activate the receptor, determine the drug's effect on the tissue.
Several parameters, such as the drug's affinity for its receptor and its efficacy, which is its ability to activate the receptor, determine the drug's effect on the tissue.