FPGEE for National Association of Boards of Pharmacy (NABP) Practice Exam

Which of the following is true about maintenance doses?

1. Dependent on the volume of distribution

2. Required for a few specific drugs only

3. Dependent on the clearance rate of the drug

4. Always administered intravenously

The correct answer is: Dependent on the clearance rate of the drug

Maintenance doses are designed to maintain a desired drug concentration in the bloodstream after an initial loading dose has been given. The key factor influencing maintenance doses is the clearance rate of the drug. Clearance refers to the volume of plasma from which the drug is completely removed per unit of time, which impacts how frequently and how much of the drug needs to be administered to keep drug levels stable. Higher clearance rates necessitate higher or more frequent maintenance doses to sustain therapeutic drug levels because the drug is eliminated from the body more quickly. Conversely, drugs with lower clearance rates may require lower or less frequent maintenance doses. Understanding this relationship is crucial in pharmacotherapy, where achieving and maintaining appropriate drug levels is necessary for efficacy while minimizing toxicity. Other options do not provide a complete or accurate picture regarding maintenance doses. While the volume of distribution plays a role in understanding how a drug distributes in the body, it is not the primary factor determining maintenance dosing. Not all drugs require maintenance doses, as some may be effective with only occasional dosing or even a single dose. Furthermore, maintenance doses can be administered through various routes, not only intravenously; oral and other routes are also common, depending on the drug's formulation and the patient's needs.