After 5 half lives _______% of the drug is gone.

After 5 half lives **97**% of the drug is gone.

_________________

Unlikey to have any more effect

Most drugs in veterinary medicine follow _________ kinetics

Most drugs in veterinary medicine follow **First Order** kinetics

Half-life (T_{1/2}) equation

t_{1/2 }= 0.693 x Vd / Cl_{B}

When saturation occurs, Cl_{B} (increases/decreases) and t_{1/2} (increases/decreases) leading to drug accumulation and potential development of side effects.

When saturation occurs, Cl_{B} (increases/**decreases**) and t_{1/2} (**increases**/decreases) leading to drug accumulation and potential development of side effects.

T/F: Half life is dose dependent

False, it is proportional

Dosage

"Recipe" for how much to give (mg/kg)

Bioavailability % (F%) equation

F% = AUC (extravascular) / AUC (IV) x 100%

F% is equal to ________ for IV administration

F% is equal to **100** for IV administration

One Compartment Model

Consider the body as consisting of a single, homogeneous compartment. Volume would equal the volume of distribution. Model may be closed or open taking in account for clearance.

Primary compartment method by which pharmacokinetic parameters are now determined in veterinary medicine

Stochastic model

(Non-Compartmental)

Zero Order Kinetics

Amount of drug is eliminated per unit time is fixed

Peak

Highest concentration of each dose

Dose

The amount of a drug given to an individual (mg)

Time to achieve steady state levels is (dependent/independent) of dose.

Independent

What are the components of a dosage regimen

Dosage

Route of Administration

Frequency

Duration

Plasma Concentration Steady State is reached at how many half lives

5

Extent

How much the mass (dose) of a drug changes in total

Loading Dose

Single dose administered to get the plasma concentration to a certain level, to be maintained by repeated dosing

Compartment Model

Views the patient as a number of compartments, each compartment is a collection of tissues that have similar pharmacokinetics

Pharmacokinetics

Use of mathematical modelsto quantitate the time course of drug disposition in man and animals

Allometric Scaling

Uses pharmacokinetic data in multiple species to try to predict the behavior of a drug in a species for which this information is unknown

What type of pharmacokinetic model is used for drugs that follow first order kinetics?

Non-Linear Model

Clearance

Volume cleared of the drug per unit time (mL/min/kg)

What happens to plasma concentration and half life if a dose is doubled?

Plasma concentration will increase

Half life will remain the same

Population Pharmacokinetics

System estimates pharmacokinetics by looking at populations. Mathematical techniques allow studies of large numbers of animals with less individual sampling. Can allow for development of parameters for a drug that would apply to all breeds/ages/genders/etc.

Elimination roughly equals

Metabolism + Excretion

As Vd increases, t_{1/2} (increases/decreases)

Increases

Multi-Compartment Model

Consists of multiple compartments. Math gets incredibly complex

Vd Equation

Vd = Dose / C_{p}

Bioavailability (F)

Fraction of the dose given which finds its way into systemic circulation