Definitions
Define and represent bioavailability
The amount of drug that is available to be absorbed into systemic circulation
Oral drugs F < 1
CSS
Steady state concentration
Primary organ of metabolism
Liver
Loading dose? (LD)
For drugs with long half lives- give LD to get the pt up to SS in order to efficiently treat their condition (like AFib)
Up regulation of receptors
The addition of new receptors due to low concentration of drug or blocked receptors
Define and give example of synergy
Synergism enhances therapeutic effect: using 2 drugs produces greater effect than 1 drug
MEC
Minimum effective concentration
Prodrug
An inactive drug that has to be converted to an active drug through metabolism
Clearance
The rate the drug is removed from the blood- someone with lowered kidney function will have a slower clearance thus needing to take less medication in order not to reach toxicity
ADME
Absorption: how the body takes in the drug
Distribution: where in the body does it go
Metabolism: how does it break down
Excretion: elimination of drug from body
Define half-life
The time it takes for the amount of drug in the body (plasma concentration) to decrease by 50%
Vd
Volume of distribution
Phase 1 vs Phase 2
P1: uses cytochromes to break down molecules
P2: adds polar bodies to inactive/make it more polar
Metabolism
Breaks drug down into metabolite (more polar) so it can be inactivated and easily eliminated
Tolerance vs Down Regulation (tachyphylaxis)
Tolerance: the gradual loss of response to a drug over long(er) period of time
Down Regulation: Desensitization/loss of response that occurs rapidly leading to decrease efficacy
Define therapeutic index and how its different from therapeutic window
Therapeutic index is a ratio and therapeutic window is a concentration- a drug with a high or wide TI is considered safer than one with a low or narrow TI
CrCl
Creatinine Clearance
First Pass Effect: what is it? What organ? What routes bypass it?
Process of how a drug is altered upon initial pass through the liver. IV, SM, and SC bypass FPE
Factors that vary the response of medication (5 things)
1. Age 2. Gender 3. Health 4. Genetics 5. Body weight/composition
What happens w/ decreased plasma protein binding
Increased volume of distribution: meaning drug is small and can distribute out of blood plasma
Define AUC
The total amount of drug that is absorbed into systemic circulation
CP
Plasma concentration
Increased bioavailability: what happens to FPE and drug amount in sys circ
Decreased FPE
Increased drug amount in system circulation
Cytochrome P450
Different drugs may use the same enzyme to break down therefore creating a drug interaction
Most abundant protein in the body?
Albumin