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
What is the main route of elimination of drugs?
Renal system
What affects elimination?
Renal blood flow and kidney function
2 Categories of drug administration
Enteral
Parenteral
First pass effect
For each drug a certain % is converted from the original “mother” compound into some intermediate metabolite
What form is the drug passed on as after first pass effect?
Either the chemically intact drug or as a metabolite
Parental Routes of Administration
IV Intra-arterial Intramuscular Subcutaneous Inhalation Topical Intraosseus transdermal Intrathecal/intraventricular (brain) (Rectal?)
IV Absorption: Continuous Infusion
Ex. IV drip; gives a regulated, consisted dose over time, causing a steady state in drug concentration
IV Absorption: Intermittent Dose
Ex. Injection; has peaks and troughs in drug concentration
Off-Label Use
use of pharmaceuticals or medical devices for an (FDA) unapproved age group, unapproved dosages, unapproved form of administration, or unapproved indication
What percent of hospitalized patients experience ADR’s? (mild to severe)
A least 5%