The document defines maintenance dose as the dose of a drug administered to replace the amount eliminated from the body during the dosing interval, in order to maintain a steady state drug level in the body. It derives the maintenance dose equation as Q = k_e D_B, where Q is the maintenance dose, k_e is the elimination rate constant, and D_B is the total amount of drug in the body at the effective drug concentration level. Alternatively, the maintenance dose can be calculated as Q = Cl_T(EDC), where Cl_T is the total clearance and EDC is the effective drug concentration.

1. Presentation
on
Maintenance dose
Prepared by:
Imran Ahammad Chowdhury

2. Maintenance Dose
Definition:
Maintenance dose is the dose of a drug administered just to replace the drug that
has been eliminated from the body during the dosing interval , so as to maintain the
steady state drug in the body. It is denoted by Q.
Derivation of Maintenance dose:
The maintenance dose range can be calculated by the familiar plateau principle
equation.

3. The equation is:
Q = 𝑘 𝑒 𝑥′ 𝑣 𝑑 ---------------------(I)
Where,
Q = maintenance dose;
𝑥 = concentration of drug at steady state level;
𝑘 𝑒 = elimination rate constant;
𝑣 𝑑 = volume of distribution.
Equation (1) can be written as follows:
Q = 𝑘 𝑒 𝐸𝐷𝐶 𝑣 𝑑 [ since 𝑥′ = effective drug concentration ]
But 𝐸𝐷𝐶 𝑣 𝑑 = Total amount of drug in the body at (EDC) level, i.e. 𝐷 𝐵.
So that, Q = 𝑘 𝑒 𝐷 𝐵 --------------------(II)

4. Alternatively, since 𝑘 𝑒 𝑉𝐷 is the total clearance 𝐶𝑙 𝑇
Q = 𝐶𝑙 𝑇 (EDC)----------------(III)
So the equation shows that , the maintenance dose rate will have to be higher , if 𝐶𝑙 𝑇 is higher.
From this equation can be calculate the maintenance dose of the drug.
THE END