During intermittent IV infusion, what determines the peak and trough concentrations, and how does this relate to clearance?

During intermittent IV infusion, what determines the peak and trough concentrations, and how does this relate to clearance?

• A. Infusion rate, dosing interval, and clearance determine Cmax and Cmin; slower clearance yields higher peaks and higher troughs.
• B. Dosing interval alone determines Cmax and Cmin.
• C. Infusion rate determines Cmax while clearance determines only Cmin.
• D. Only the infusion duration determines Cmax and Cmin.

Answer: (A)

During intermittent IV infusion, the concentration profile rises as the drug is delivered and falls as it is cleared between doses. The peak concentration at the end of an infusion, and the trough just before the next dose, are shaped by how much drug is given and how it is delivered, how often doses are given, and how quickly the body removes it. A faster infusion rate or a shorter infusion duration (for the same overall dose) delivers drug more quickly, pushing the end-of-infusion concentration higher (higher Cmax). The dosing interval sets how long the body has to clear the drug before the next dose; shorter intervals reduce the trough by leaving more drug in the body, while longer intervals allow more elimination and lower troughs. Clearance dictates how fast elimination occurs; slower clearance means the drug stays longer in the body, raising both the peak at the end of infusion and the trough before the next dose. So Cmax and Cmin in intermittent IV dosing are determined by infusion rate, dosing interval, and clearance, with slower clearance causing higher peaks and higher troughs.

During intermittent IV infusion, the concentration profile rises as the drug is delivered and falls as it is cleared between doses. The peak concentration at the end of an infusion, and the trough just before the next dose, are shaped by how much drug is given and how it is delivered, how often doses are given, and how quickly the body removes it. A faster infusion rate or a shorter infusion duration (for the same overall dose) delivers drug more quickly, pushing the end-of-infusion concentration higher (higher Cmax). The dosing interval sets how long the body has to clear the drug before the next dose; shorter intervals reduce the trough by leaving more drug in the body, while longer intervals allow more elimination and lower troughs. Clearance dictates how fast elimination occurs; slower clearance means the drug stays longer in the body, raising both the peak at the end of infusion and the trough before the next dose. So Cmax and Cmin in intermittent IV dosing are determined by infusion rate, dosing interval, and clearance, with slower clearance causing higher peaks and higher troughs.