Kinetics and dynamics Flashcards
1
Q
what is pharmacokinetics
A
- how the body handles the drug
- how the drug moves within the body
2
Q
what are the four processes of pharmacokinetics
A
- absorption (in the stomach and duodenum)
- distribution
- metabolism
- excretion
3
Q
what is absorption
A
- first step in drug transport
- movement of drug from site of administration across one or more body membranes
- drug is transferred from the formulation into the blood
4
Q
what types of factors can help increase the rate of absorption/distribution
A
- injection
- liquids (faster than solids)
- gas (faster than liquids)
- smaller
- hotter
- empty stomach (less competition = fast absorption)
- more soluble will make it faster
5
Q
what is distribution
A
- process by which drugs are transported after absorption or direct administration into blood
6
Q
what are some factors that affect distribution
A
- plasma proteins
- bioavailability
- anatomical barriers; how well the drug passes through these barriers is the one factor that determines its ultimate effectiveness
7
Q
what is metabolism
A
- the sum total of all chemical reactions in the body
- drug is transformed by body processes
- biotransformation
8
Q
what is the primary site of metabolism
A
- the liver
9
Q
what is the function of metabolism
A
- deactivate most drugs
- prodrugs more active after metabolism
- first pass effect via hepatic portal circulation
10
Q
what is the first pass effect
A
- drugs given orally are absorbed through the intestinal wall and enter the hepatic portal circulation where they are taken directly to the liver for metabolism before reaching the heart and circulating throughout the rest of the body
11
Q
what are some factors that affect metabolism
A
- differing metabolic enzyme function
- age
- kidney disease
- liver disease
- genetics/race
- other medications and foods
12
Q
what is excretion
A
- the removal of substances from the body
- via kidneys, respiratory tract, bile or glands
13
Q
what is the primary organ involved with excretion
A
- the kidney (removes all unnatural and harmful agents in the blood while maintaining balance of natural substances)
14
Q
what is the rate of elimination
A
- amount of drug removed per unit of time
- determines how long the drug remains in the bloodstream
- determines how long the drug will produce its effect
15
Q
what is half life
A
- t 1/2
- the length of time for a drug to decrease concentration in the blood by half
- how long the drug will produce its effect
- increased in renal or hepatic diseases