1: intro Flashcards
definition of drug
a CHEMICAL utilized for diagnosis, prevention, cure, or amelioration (make less bad) of an unwanted health condition
- all drugs are chemicals
- all drugs are poisons (helpful at a correct dose)
natures of drugs
physical (solid, liquid, gas)
size (small, very small, very large) - affects method of administration
drug-receptor interactions: electrostatic bonds (ionic, hydrophobic, van der waals)
shapes: complementary to receptor
exists in racemic mixture (1:1 R:S isomer)
Why might some drugs be administered intravenously?
too large, cannot be absorbed through intestinal wall
direct, faster
What is pharmacodynamics?
what drug does to the body
What is pharmacokinetics?
what the body does to the drug, how it handles a drug (signalling and responses)
What is the principle of PK/PD?
the action of the body to the drug determines its concentration at the receptor site
the concentration of drug at its site of action determines its action in the body, both therapeutic or toxic
what is therapeutic index?
ratio of conc where drug becomes toxic and conc where the drug is therapeutic
TI = TD50/ED50
dose at which toxic effects shown in 50% of patients
dose at which therapeutic effects shown in 50% of patients
higher TI = safer drug (wider margin of safety, less easy to cross the toxic dose)
drugs with narrow therapeutic index
theophylline (bronchodilator, inhibits PDE)
cyclosporine (t-cell selective immunosuppressant, inhibits calcineurin)
need to be titrated
drugs with wide therapeutic index
ibuprofen
acetaminophen
antihistamines
beta blockers (heart and lungs)
drug categories
over the counter
pharmacy-only medicines
prescription-only
What are the sources of drugs?
animals, plants, marine, microorganisms, semisynthetic (eg purification), chemical synthesis, biologics
What are some drug targets?
receptors, ion channels, nuclear receptors, enzymes, hormones, nucleic acid
