How Grapefruit Interacts with Medications
Grapefruit and its juice can alter how certain medications are absorbed into the bloodstream, potentially causing severe side effects or reducing the effectiveness of the medication. This interaction is primarily due to furanocoumarins—compounds in grapefruit that interfere with enzymes and proteins in the small intestine responsible for drug metabolism.
Why Grapefruit Affects Medications
Furanocoumarins disrupt the function of enzymes like cytochrome P450 3A4 (CYP3A4), a key enzyme that helps metabolize many drugs. When CYP3A4 is blocked, more of the drug enters the bloodstream and stays in the body longer, potentially leading to adverse effects. For example, blood pressure medications like nifedipine (Procardia) can cause dangerously low blood pressure when combined with grapefruit.
Examples of Medications Affected by Grapefruit:
1. Blood Pressure Medications: Grapefruit can increase levels of drugs like nifedipine, causing low blood pressure and slow heart rates.
2.Cholesterol-Lowering Statins: Statins like simvastatin (Zocor) and atorvastatin (Lipitor) can accumulate to toxic levels, leading to muscle pain and damage.