Which statement about selectivity and side effects is true?

Which statement about selectivity and side effects is true?

• A. Higher selectivity decreases side effects
• B. Higher selectivity increases side effects
• C. Selectivity has no effect on side effects
• D. Side effects depend only on dose

Answer: (A)

A drug that is highly selective tends to bind mainly to its intended target and avoids activating or blocking other receptors or tissues. This focus limits off-target actions, which are usually the source of unwanted side effects. So, increasing selectivity generally lowers the likelihood and severity of adverse effects. Keep in mind that side effects can still occur if the dose is high enough to engage other targets, or if metabolites have their own activities, but the basic idea holds: greater selectivity reduces off-target effects, whereas simply relying on dose alone doesn’t explain why side effects appear or disappear.

A drug that is highly selective tends to bind mainly to its intended target and avoids activating or blocking other receptors or tissues. This focus limits off-target actions, which are usually the source of unwanted side effects. So, increasing selectivity generally lowers the likelihood and severity of adverse effects.

Keep in mind that side effects can still occur if the dose is high enough to engage other targets, or if metabolites have their own activities, but the basic idea holds: greater selectivity reduces off-target effects, whereas simply relying on dose alone doesn’t explain why side effects appear or disappear.