Foundations in Pharm Flashcards
4 key components of assessment of drug therapy
- indication
- effectiveness
- safety
- adherence
4 phases of pharmacokinetics (ADME)
- absorption
- distribution
- metabolism
- excretion
factors influencing PK and PD
- physiologic
- pathophysiologic
- genetic variability
- drug interactions
pharmacokinetics (definition)
the study of drug movement through the body
what the. body does to the drug
3 ways for a drug to cross a cell
- direct penetration of cell membrane
- channels and pores
- transport systems
what’s absorption in PK?
mvnt of a drug from site of administration into the blood
Factors affecting drug absorption (5)
rate of dissolution
surface area
blood flow
lipid solubility
pH
two routes of absorption
enteral vs parenteral
bioavailibility (F)
F= amount of drug absorbed/drug dosage
bioavailability is affected by (3)
- gastric empty tiem
- pH of the stomach
- speed the drugs moves through the GI tract
bioavailability of IV therapy is __
100%
bioavailability
bioavailability: ability of drug reaching the systematic circulation from the site of administration.
Bioequivalence
bioequivalence: two different drugs or different dosage forms of the same drug produce the same concentration vs drug time (generic products)
What’s the first pass effect?
drugs given orally are absorbed through GI tract and carried to liver
liver metabolizes the drug BEFORE reaching the systemic circulation, large drug inactivated, leading to decrease in therapeutic effect
administer drugs via parenteral, sublingual, transdermal, etc. e.g. nitroglycerine
distribution
mvnt of drugs form the blood to various tissues
volume of distribution
amount of drugs in the body/ plasma concentration
4 factors affecting distribution
- blood flow
- lipophilicity
- molecular size and weight
- drug protein binding
High protein-bound drugs
gradual release (blood is reservoir)
Low protein-bound drugs
immediate release
consequences of drug metabolism
- accelerated renal excretion
- drug inactivation
- increased therapeutic action
- activation of prodrugs
- increased toxicity
Enzyme inducer__ level of drug in the body
Enzyme inhibitor___ level of drug in the body
Enzyme inducer decrease
Enzyme inhibitor increase
metabolism
enzymatic alteration of drugs
3 processes of renal drug excretion
- glomerular filtration
- passive tubular reabsorption
- active tubular secretion
factors modifying renal drug excretion
- pH dependent ionization
- competition for active tubular transport
- age. (newborns have limited capacity to excrete drugs)