Fundamentals Flashcards
What drugs do to the body
Pharmacodynamics
What the body does to drugs and how fast it does it (absorption, distribution, metabolism, excretion)
Pharmacokinetics
absorption and distribution of drugs is determined by:
1) Drug molecular size
2) Drug solubility
3) Conditions at site of tissues to be penetrated by drug (e.g. inflamm.)
The ________ portion of the membrane is the most difficult portion for a drug to penetrate
lipid
**Drugs that are lipid soluble (non-polar) are able to penetrate membranes more rapidly than those that are polar
Drugs that activate receptors
agonists
Drugs that block receptors
antagonists
dose required to produce minimum response
potency
maximum magnitude of response
efficacy
margin of safety
difference between toxic and effective dose
therapeutic index
ratio of toxic and effective dose (toxic divided by effective)
duration of action
amount of time that drug acts
half-life
time required for 1/2 of drug to be eliminated
Most drug/receptor bonds are ___________ bonds
reversible ionic
Measures of desirable drug actions include:
Efficacy and Potency
When is a drug considered toxic?
When the effective dose and lethal dose are similar
3 ways drug actions are ended
redistribution, metabolism, excretion
the drug is carried away from the site of action, usually by blood flow
redistribution
the drug is modified to make it less active or more readily excreted
metabolism
the drug is (or its metabolite) is removed from the body
excretion
The __________ is the major organ of drug excretion
kidney
What might happen to a patient with renal pathology?
build up of drugs in the body b/c they’re not being excreted - the accumulated drugs can cause toxic effects
The ________ is the major organ for metabolizing drugs
liver
**this makes it less active and/or more excretable by the kidney
first-pass metabolism
a swallowed drug goes into the digestive system and then hepatic system before entering circulation to the rest of the body - this great reduces the bioavailability of the drug
enterohepatic cycle
refers to the cycle of biliary contents, drugs, or other substances from the liver to the bile, and then into the small intestines…ultimately back to the liver and so on. This is often associated with multiple peaks and a longer half-life
_________ occurs in lipophilic ER of liver and other cells, and features redox rxn that polarize drug molecule, making them more excretable
Phase I Metabolism
rate limiting rxn of phase I metabolism require
cytochrome P450 enzyme
CYP
In __________ endogenous molecules are coupled with parent drugs or metabolites via transferase enzymes, resulting in conjugates that are larger and more excretable
Phase II Metabolism
Schedule I drugs
1) High potential for abuse, severe physical and psychological dependence
2) No accepted medical use
3) Use for research only
4) Not to be prescribed, unsafe for tx
Schedule II drugs
1) High potential for abuse, severe physical and psychological dependence
2) Acceptable medical uses, w/ restrictions
3) Dispensed by Rx only
4) No refills w/out new written Rx from doc
Schedule III drugs
1) moderate potential for abuse, high psychological dependence, low physical dependence
2) acceptable medical uses
3) by Rx only; may be refilled 5X in 6 mo. if authorized by doc
Schedule IV drugs
1) lower potential for abuse than Sched. III; limited psychological and physical dependence
2) Acceptable medical uses
3) by Rx only; may be refilled 5X in 6 mo. if authorized by physician
Schedule V drugs
1) low potential for abuse
2) acceptable medical uses
3) OTC narcotic drugs, but sold only by registered pharmacists; buyer must be 18 y/o and show ID
Schedule VI drugs
1) medical marijuana
2) needs Rx
*only some states uses Sched. VI category
