Which of the following substances is known to induce CYP3A4?

Rifampin is known to induce CYP3A4, which is a critical enzyme involved in the metabolism of various medications. Inducers like rifampin increase the activity of enzymes, leading to enhanced metabolism of drugs that are substrates of CYP3A4. This means that when rifampin is present, it can significantly lower the plasma concentrations of other medications metabolized by this pathway, potentially decreasing their effectiveness.

In contrast, grapefruit juice is known to inhibit CYP3A4, leading to increased levels of substrates in the bloodstream. Amlodipine does not induce CYP3A4; instead, it is primarily metabolized by this enzyme without inducing its activity. Clarithromycin also inhibits CYP3A4 rather than inducing it. Understanding these interactions is crucial for safe and effective medication management in clinical practice.