Pharm 1 Lecture Flashcards
Pharmacology
the study of drugs and their action on a critter’s body
Drugs
substances which can affect a critter
Pharmacodynamics
the branch of pharmacology dealing with reactions between drugs and living systems
what a drug does to a critter
Pharmacokinetics
mathematical description of the processes through which a drug is handled once introduced into the body
what the critter does to the drug
toxicology
the study of how drugs poison cells, critters and/or ecosystems
LADME
liberation, absorption, distribution, metabolism, elimination
Liberation
process of the drug being “liberated” from its carrier tablet, capsule, etc.
aka disintegration
Absorption
the nature and characteristics of how a drug moves from its site(s) of administration into the critter’s plasma (usually)
What variables affect absorption past a membrane?
Size of drug molecule (small ones go through)
Ionization of drug (nonionized go through)
Lipid solubility (lipophilic go through)
pH
Administration route
Dosage form
Drug solubility
Distribution
dissemination of a drug throughout the “compartments” of a critter’s body, such as plasma, tissues, or organs
Where are IV drugs preferentially absorbed on bypass?
Muscle or brain; won’t be disseminated equally; depends how easily it moves into the membrane
What is the major vehicle for distribution of drug?
Bloodstream
What can affect distribution of a drug?
blood flow, fat, or water solubility
protein binding
Metabolism
the biotransformation of a drug into other (secondary) compounds (which can also be drugs). Frequently a task performed by the critter’s liver (kidney, skin, lungs too)
After the drug has been absorbed and distributed, what happens?
The body work to break it down via metabolism into metabolites
What is the major organ for metabolism?
Liver
How does the liver metabolize?
Via drug oxidation by the Cytochrome P-450 enzyme system
Cytochrome P-450 enzyme system
enzymes induce (increase) or inhibit (decrease) metabolic activity.
Why do people who frequently drink alcohol become more tolerant to it?
enzyme induction by the cytochrome P-450 enzyme system
What kind of metabolism capability does the fetal liver have?
Fetal liver has 1/3 the drug metabolism capacity as the adult liver therefore metabolism is reduced at birth
Aging accounts for what percent reduction of liver mass?
20-30% of liver mass
Elimination/Excretion
process that removes a drug from an organism in urine, feces, etc. IF a drug isn’t removed fast enough it bio-accumulates in the critter
How can drugs be excreted?
Urine, Feces, pulmonary system, skin and hair
What affects metabolism?
Liver function and enzymes