Pharmacokinetics and drug formulations

Question 1

Pharmacokinetics definition

Answer 1

what the body does to the drug

Question 2

pharmacodynamics

Answer 2

what the drug does to the body

Question 3

what factors can decrease dissolution of a medication in the gut?

Answer 3

1. hydrolysis: water destroys the molecule

2. the drug does not dissolve well in acid or the stomach is not acidiec enough

Question 4

which equation describes the rate of dissolution?

Answer 4

the noyes-whithney equation

Question 5

where is the major site of drug absorption?

Answer 5

the small intestine

Question 6

in what PH do enteric formulations get absorbed

Answer 6

in basic environments like in the small intestine

Question 7

why can AMG no be given PO?

Answer 7

they are polar charged molecules that cant pass through cell walls. The remain in blood more and thats one reason they are nephrotoxic

Question 8

what are two of the most common protein-bound medications?

Answer 8

phenytoin and warfarin

Question 9

when is elimination of a medication considered complete?

Answer 9

after 4-5 half lives

Question 10

what is first order kinetics?

Answer 10

the amount of drug given is proportional to the increase seen in plasma concentration. The more you give of a drug, the higher the drug concentration

Question 11

what is michaelis menten kinetics?

Answer 11

at first, an increase in drug is proportional to its concentration in the blood. That is until, the metabolizing enzymes become saturated. Then the elimination rate of the drugs becomes independent of the drug concentration: the amount can increase dramatically and lead to toxicty

Question 12

what are three main examples of drugs that follow michaelis menten kinetics?

Answer 12

phenytoin
voriconazole
theophylline

Question 13

what are good formulations for people who have trouble swallowing?

Answer 13

orally disintegrating tablets
patches
some bead formulations sprinkled onto food
suppository
IV

Question 14

why are migraine medications in ODT form?

Answer 14

because migraines usually cause nausea and these meds can cause nausea when swallowed. So giving ODT reduces nausea

Question 15

what formulations are better for patients that are non-adherent?

Answer 15

Long acting formulations

Question 16

what is the main cause of side effects

Answer 16

when you get a quick peak vs a gradual rise in the concentration of the drug. This allows the drug to interacat with the wrong receptors, leadingto side effects.

Question 17

which medications should not be crushed or chewed?

Answer 17

long-acting: XR, ER, LA, SR, CR,

CRT, SR, TR, TD, have 24 or end in -CONT Contin, or are sprinkles or timecaps

Question 18

which XL formulation can be cut in half?

Answer 18

Toprolol XL

Question 19

why does mesalamine come as a suppository?

Answer 19

because the diseases is found n the distal portion of the intestine: reduced SEs

Question 20

can patches be cut? which are exceptions?

Answer 20

usually you cannot. Exception is lidoderm. YOu can cut it and put over the painful area

Question 21

should patches be exposed to heat?

Answer 21

almost all cases no. Esp from a fever, an electric blanket or heating pad

Question 22

what to do when a patch is bothering a persons skin?

Answer 22

1. make sure they are changing where they apply the patch every time
2. dont shave before hand in that area
3. Can apply hydrocortisone OTC (if the skin is already irritated from being w/ a patch on )

Question 23

common patches that need to removed before MRI

Answer 23

nicotine
testosterone
fentanyl
clonidine 
and more

Question 24

what to do about problems with sticking and unsticking?

Answer 24

• do not cover it with tape in most cases
• they dont stick to lubricated skin
• make sure to press down for the adequate amount of time
• does not stick to hairy skin. Shave in advance or cut hair close to skin, or use a non hairy site

Question 25

how freqently to put on fentanyl patch

Answer 25

q 72h

Question 26

how freqently to put on nicotinel patch

Answer 26

every day

Question 27

how freqently to put on lidoderm patch

Answer 27

1-3 patches on for 12 hours, then off for 12 hours

Question 28

where is the transdermal scopolamine patch placed?

Answer 28

behind the ear, alternating ears

Question 29

where to place estrogen patches:

Answer 29

mostly lower abdomen, some upper buttock. Never breasts

Question 30

where to place topical pain patches:

Answer 30

over painful areas except for opiods which work systemically

Question 31

how to discard patches

Answer 31

fold patch, pressing adhesives together and discard
fentanyl can be folded and flushed. Or ti can be cut up and mixed wit/ noxious substances and then thrown in the trash
Can also flush buprenorphine