The total body clearance is the volume of the plasma or blood which is completely cleared from the drug per unit time. It has units of volume/time.

The CL_T for a drug is constant within a patient (dose and concentration independent) when the elimination processes follow first-order kinetics.

The total body clearance is a measure of the efficiency of all eliminating organs in eliminating the drug and it is the sum of all organ clearances (i.e. CL_T is the sum of the renal clearance, hepatic clearance and all other organ clearances).

The elimination rate constant and the half life (the dependent pharmacokinetic parameters) are dependent on (is determined from) the total body clearance and the volume of distribution (the independent pharmacokinetic parameters).

The metabolite total body clearance is the volume of the plasma or blood which is completely cleared from the metabolite per unit time. It has units of vloume/time.

The CL_T(m) for the metabolite is constant within a patient (dose and concentration independent) when its elimination processes follow first-order kinetics.

The CL_T(m) is a measure of the efficiency of all eliminating organs in eliminating the metabolite.

The metabolite elimination rate constant and the metabolite half life (the dependent pharmacokinetic parameters) are dependent on (is determined from) the metabolite total body clearance and the metabolite volume of distribution (the independent pharmacokinetic parameters).

The amount of the metabolite formed after drug administration depends on the dose of the drug and f_m. If f_m is equal to unity (1) for a particular metabolite, this means that the entire dose of the parent drug is converted to that metabolite.

Drugs that undergo parallel metabolism to more than one metabolite have different f_m values for each metabolite. The sum of these f_m values should not m m be more than one, but it does not have to be equal to one (when the drug elimination involves a pathway other than metabolism).

This fraction should be dose independent when drug elimination follows first-order kinetics. Also, this fraction should not be different for a particular drug in a particular patient after different routes of administrations, if the metabolite is not formed during drug absorption after extravascular administration.

It is the integral of the metabolite plasma concentration-time profile from time zero to time infinity.

It has units of mass-time/volume.

The metabolite area under the curve after a single drug administration is dependent on the amount of the metabolite formed in vivo and the metabolite total body clearance.

It is the integral of the plasma concentration-time profile from time zero to time infinity.

It has units of mass-time/volume.

The area under the curve after an iv administration is dependent on the administered dose and the total body clearance.

The steady state is the condition when the rate of drug administration is equal to the rate of drug elimination.

When the drug is administered as a constant rate IV infusion, there will be one steady state concentration as long as the rate of administration and the rate of elimination do not change.

The time required to achieve steady state is dependent on the drug half life. It takes about 5-6 half lives to achieve steady state. The steady state concentration during constant rate iv infusion is directly proportional to the infusion rate and inversely proportional to the total body clearance of the drug.