Final definitions Flashcards
drug
a chemical agent used in the dx, tx or prevention of disease
Drug routes
enteral, parenteral, inhalation, intranasal, intrathecal, topical, transdermal, sublingual, and IV
What’s unique about sublingual route?
drug delivered to blood stream, skips first pass by liver
What’s unique about IV route?
100% bioavailability
Drug absorption rule
small non-ionized, lipid soluble drugs will more readily cross plasma membrane relative to larger, ionized and/or water soluble molecules
bioavailability
is the fraction of administered drug that reaches the systemic circulation in an unchanged form. Solubility of agent, hepatic metabolism of agent, and chemical binders influence bioavailability.
Half life
is the amount of time required for the plasma concentration of a drug to decrease by 50% after discontinuation of the drug.
loading dose
initial dose of drug that is higher than subsequent doses for purpose of achieving therapeutic drug concentration.
maintenance dose
dose of a drug that maintains a steady state plasma concentration in therapeutic range.
onset
amount of time it take for a drug to exert effects
Duration
the length of time for which a drug exerts therapeutic effects.
Efficacy
refers to the degree to which a drug is able to induce maximal therapeutic effects. Efficacy is a term often used to compare drugs of different classes.
Potency
is the amount of drug required to produce 50% of the maximal response that the drug is capable of producing. Potency is more frequently used to compare drugs of similar classes.
EC50
: effective concentration 50 is the concentration of an agent which induces a specific clinical effect in 50% of subject to which drug has been administered.
LD50
lethal dose 50 is the concentration of an agent which causes death in 50% of subject to which that agent has been administered.
Therapeutic index: (TI)
(TI) = LD50/EC50. - A measure of drug’s safety. Large number is good, small number is bad.
Agonist
an agent that can bind to a receptor site and elicit a defined therapeutic response
partial agonist
occupies a binding site but causes less of response than a full agonist
antagonist
inhibit or block response caused by agonist
competitive antagonist
interact with receptors at the same site as agonist and thus compete for binding.
non-competitive antagonist
bind to a site other than the agonist. (effects are generally irreversible)
tolerance
a decreased response to a drug. Clinically dose of drug must be increased to achieve a similar effect of the drug at its original dose.
supplement
intended to “supplement the diet”, contains vitamins, minerals, herbs or botanicals, or a concentrate/metabolite/constituent or combo of these things.
- May not claim to treat, diagnose, cure or prevent disease
- Can make “structure or function claims”….. can support joints…etc.
pregnancy Rx classification
- A: controlled studies show no risk
- B: no evidence of risk in humans
- C: risk cannot be ruled out
- D: positive evidence of human fetal risk
- X: contraindicated in pregnancy
o Most drugs are category C— so contraindicated w/ pregnancy.
FDA/DEA classification Rx
CI: no approved medical use (LSD, heroine)
CII: high potential for abuse, increased rate of addiction, need a new script to refil.
CIII: moderate potential for abuse
CIV: low potential for abuse (lowest dose of codeine)
OTC: available over the counter.
