Which term describes the ability of certain drugs to bind to plasma proteins, thereby influencing the amount of drug available at the site of action?

Which term describes the ability of certain drugs to bind to plasma proteins, thereby influencing the amount of drug available at the site of action?

• A. Side effects
• B. Protein binding
• C. Tmax
• D. STAT

Answer: (B)

Protein binding describes how certain drugs attach to plasma proteins in the blood, which determines how much drug is free to reach the site of action. Only the unbound portion can cross capillary walls, distribute to tissues, and interact with receptors to produce effect. The bound portion acts as a reservoir, slowing distribution and elimination and shaping both the onset and duration of action. Thus, the ability of a drug to bind to plasma proteins directly influences the amount of active drug available where it works. The other terms don’t describe this binding phenomenon: Tmax is about time to peak concentration, side effects are adverse effects, and STAT isn’t a pharmacology term used for this concept.

Protein binding describes how certain drugs attach to plasma proteins in the blood, which determines how much drug is free to reach the site of action. Only the unbound portion can cross capillary walls, distribute to tissues, and interact with receptors to produce effect. The bound portion acts as a reservoir, slowing distribution and elimination and shaping both the onset and duration of action. Thus, the ability of a drug to bind to plasma proteins directly influences the amount of active drug available where it works. The other terms don’t describe this binding phenomenon: Tmax is about time to peak concentration, side effects are adverse effects, and STAT isn’t a pharmacology term used for this concept.