Question

Maintenance dose is calculated by using the value of?

• A. Clearance
• B. Volume of distribution
• C. Oral bioavailability
• D. Daily dosage

Hint:

At steady state, dosing rate replaces elimination rate - which depends on this parameter.

Answer 1

The Correct Option is A

Step 1: To sustain a therapeutic level, the amount of drug delivered per unit time must replace the amount the body removes per unit time once steady state is reached.

Step 2: The body's capacity to remove the drug is quantified by clearance. With a desired steady-state concentration $C_{ss}$, the dosing rate equals $CL \times C_{ss}$, so clearance directly sets the maintenance regimen.

Step 3: It is worth distinguishing this from the loading dose, which fills the apparent distribution space and is computed from the volume of distribution rather than clearance.

Step 4: Bioavailability merely adjusts for the fraction absorbed orally, and daily dosage is a derived figure. The fundamental parameter for maintenance dosing is clearance.

\[\boxed{\text{Clearance}}\]