Drug action is affected by which factors?

Drug action is affected by which factors?

• A. The color of the tablet
• B. The degree of affinity with the receptor and its ability to produce an effect
• C. The route of administration only
• D. The age of the patient

Answer: (B)

Drug action centers on how the drug interacts with its receptors. The key is two properties: affinity, which is how tightly the drug binds to the receptor, and intrinsic activity (efficacy), which is the ability of the bound drug to produce a response. A drug with high affinity binds readily, and if it has good efficacy, it generates a strong effect. If it binds well but has little efficacy, the response is weak despite binding. If both affinity and efficacy are high, you get a pronounced effect. The other options don’t describe how the drug produces its action: tablet color is irrelevant to action, patient age can influence overall handling of the drug but not the binding-and-response mechanism, and route of administration affects how much and how fast the drug reaches the receptor but doesn’t define the action itself.

Drug action centers on how the drug interacts with its receptors. The key is two properties: affinity, which is how tightly the drug binds to the receptor, and intrinsic activity (efficacy), which is the ability of the bound drug to produce a response. A drug with high affinity binds readily, and if it has good efficacy, it generates a strong effect. If it binds well but has little efficacy, the response is weak despite binding. If both affinity and efficacy are high, you get a pronounced effect. The other options don’t describe how the drug produces its action: tablet color is irrelevant to action, patient age can influence overall handling of the drug but not the binding-and-response mechanism, and route of administration affects how much and how fast the drug reaches the receptor but doesn’t define the action itself.