What principle is demonstrated by Walter's low blood pressure due to his grapefruit juice consumption while on medication?

The principle that Walter's low blood pressure due to grapefruit juice consumption while on medication demonstrates is drug or food interaction. Grapefruit juice is known to affect the metabolism of certain medications, particularly those processed by the liver enzymes known as cytochrome P450. When grapefruit juice is consumed, it can inhibit these enzymes, leading to increased levels of the medication in the bloodstream. This can cause enhanced effects of the medication, such as a significant drop in blood pressure if the drug in question is designed to lower blood pressure.

In this scenario, Walter's grapefruit juice consumption altered the way his body processed his medication, showcasing how certain foods can interact with medications, leading to potentially harmful effects or intensified responses. Recognizing such interactions is crucial for patient safety and effective medication management. It’s important for patients to be aware of which foods or beverages could interact with their prescriptions to prevent adverse effects.