Grapefruit, wine, and St. John's Wort have no noticeable impact on drug absorption or effectiveness.

• A. True
• B. False
• C. They only affect absorption
• D. They only affect effectiveness

Answer: (B)

Interactions between what you drink or take as supplements and medications can change how a drug is absorbed and how well it works. Grapefruit juice blocks enzymes in the gut (intestinal CYP3A4) that normally break down many oral drugs. When these enzymes are inhibited, more of the drug enters the bloodstream, raising blood levels and increasing the risk of side effects or toxicity for drugs that are CYP3A4 substrates.

St. John’s Wort, on the other hand, ramps up the activity of certain drug-metabolizing enzymes (notably CYP3A4) and transport proteins. This makes drugs get cleared from the body faster, often lowering their blood levels and diminishing their effectiveness—potentially leading to treatment failure with medications like oral contraceptives, statins, or some antidepressants.

Alcohol can also affect drug absorption and metabolism in various ways and can intensify the effects or toxicity of many drugs, especially central nervous system depressants, or alter liver processing of others.

So, the statement that grapefruit, wine, and St. John’s Wort have no noticeable impact on drug absorption or effectiveness is not correct.