Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
38 Cards in this Set
- Front
- Back
|
what are the four cardinal principals of pharmacodynamics?
|
all drugs are poisons in sufficient quantity
No drug has a single action. All drugs have multiple actions. The proper dose of a drug is that amount of a drug that is needed to perform the intended action. Drugs alter existing physiological functions; they do not create new functions. |
|
|
what is miosis?
|
constriction of the pupil of the eye
|
|
|
what is mydriasis?
|
dilation of the pupil
|
|
|
describe what happens in person A (on a high-salt diet) and in person B (on a low-salt diet), when they are treated with DOCA (synthetic aldosterone)
|
A: person has a high concentration of NaCl in the blood, so they have no natural aldosterone circulating; upon adding DOCA they have a huge Na retention
B: person has a low NaCl concentration, so they have a high circulating level of aldosterone; when DOCA is added their Na retention increases only minimally |
|
|
what are the storage tissues for drugs?
|
fat for lipophilic drugs
water for hydrophilic drugs |
|
|
what is the most common method for drugs to cross biological membranes?
|
passive transport
|
|
|
describe simple diffusion
|
requires no energy
depends on a concentration gradient (moves down the gradient) requires the drug to have at least some lipid-solubility |
|
|
describe active transport
|
requires energy
movement against a gradient selective saturable |
|
|
describe facilitated diffusion
|
selective
saturable does not require energy movement down concentration gradient |
|
|
what factors affect drug absorption?
|
solubility
dissolution rate concentration at site circulation to site area of absorbing surface size of molecule contact time |
|
|
how does contact time affect drug absorption?
|
contact time is how long the drug is in contact with the absorbing surface of the intestine
increased motility causes shorter contact time and thus less absorption |
|
|
what is enteral?
|
a term used to describe routes of drug administration that involve absorption of the drug through the gastrointestinal tract
|
|
|
what is parenteral?
|
a route of administration that bypasses the GI tract
|
|
|
what are the advantages/disadvantages of oral drug administration?
|
common
convenient good safety (drug can be recovered if necessary) |
|
|
what are the advantages of sublingual drug administration?
|
avoids liver (direct absorption to systemic circulation) so that liver doesn't metabolize all of the medicine
|
|
|
what is the use for rectal drug administration?
|
used to treat nausea/vomiting
|
|
|
what are the three types of injections?
|
intravenous (IV)
intramuscular (IM) subcutaneous |
|
|
what are the advantages of intramuscular injections?
|
in case of OD, the injection site can be cooled to slow absorption
frequently used for depository injections (drugs with a very low dissolution rate) |
|
|
what are the types of enteral drug administration?
|
oral
sublingual rectal |
|
|
what are the types of parenteral drug administration?
|
Injection (IV, IM, subQ)
Topical Inhalation Transdermal |
|
|
what is the difference between topical and transdermal drug administration?
|
in transdermal administration, there is systemic absorption of the drug
in topical administration, there is no systemic absorption of the drug |
|
|
how does the pH of the GI tract affect enteral absorption?
|
could cause the drug to pick up a charge (generally, charged drugs are absorbed less than uncharged drugs)
|
|
|
how does the stomach and intestinal contents affect enteral absorption?
|
as a general rule, food slows the rate of absorption & may decrease the extent of absorption
|
|
|
what are excipients?
|
generally a pharmacologically inactive substance used as a carrier for the active ingredients of a medication
generally all that's different between generic and brand name, but can change drug absorption |
|
|
what is first pass hepatic metabolism?
|
a phenomenon of drug metabolism whereby the concentration of a drug is greatly reduced before it reaches the systemic circulation; the fraction of lost drug during the process of absorption which is related to the liver
|
|
|
what is bioavailability?
|
amount of drug which is available to the circulation past the liver
= (AUC oral) / (AUC injected) x 100 |
|
|
what is included in the plasma concentration of drug?
|
free drug concentration
protein-bound drug concentration |
|
|
what is F?
|
bioavailability
|
|
|
what form of a weak acid diffuses more easily across membranes?
|
protonated
|
|
|
what form of a weak base diffuses more easily across membranes?
|
deprotonated
|
|
|
what equation is used to predict the degree of a drug's ionization?
|
Henderson-Hasselbach equation
pH = pKa + log ( A- / HA ) pH = pKa + log ( B / HB+ ) |
|
|
what form of a drug predominates when the pH is less than the pKa?
|
protonated forms (HA and BH+)
|
|
|
what form of a drug predominates when the pH is higher than the pKa?
|
deprotonated forms (A- and B)
|
|
|
what forms of a drug predominate when pH equals pKa?
|
HA = A-
BH+ = B |
|
|
what are the two phases of a drug distribution diagram (amount of drug in blood vs. time)?
|
distribution phase (curved)
excretion phase (should be curvilinear) |
|
|
what are the water compartments in the body?
|
2/3 of total body water is intracellular
1/3 of total body water is extracellular 2/3 of extracellular fluid is interstitial 1/3 of extracellular fluid is plasma |
|
|
what is a drug's volume of distribution?
how is it calculated? |
the volume of fluid into which the drug is distributed
VD = (TD) / Px VD = volume of distribution TD = total dose Px = plasma drug concentration |
|
|
if a patient has a total body water volume of 42 liters, how can a drug's volume of distribution be 96 liters?
|
the drug is concentrated in reservoirs
|
