Chapter 2 Flashcards
define pharmacodynamics
how drug affects body; interaction between chemical components of the living system & the foreign chemicals
4 ways drugs work in body
Replace or substitute missing chemicals
Increase or stimulate certain cellular activities
Depress or slow cellular activities
Interfere with functioning of foreign cells
define agonist
produces a greater maximal response than endogenous chemicals - reinforces response
define partial agonist
produces weaker/less effective response
define antagonist
inhibits response from original chemical - competes for binding sites of endogenous chemicals
define selective toxicity
ability of a drug to affect only systems found in foreign cells without affecting human cells
example of drugs c and s selective toxicity
antibiotics
chemotherapy
define pharmacokinetics
way body deals with the drug
4 main pharmacokinetic processes
absorption
distribution
metabolism/biotransformation
excretion
examples of absorption sites of drug
enteral
parenteral
mucous membranes/topical
inhaled
3 mechanisms of absorption
diffusion
active transport
filtration
primary vehicle of distribution
blood
factors affecting distribution
tissue perfusion
cold environment
protein bound drugs (makes it difficult for drugs to cross membranes)
blood brain barrier
drugs will readily cross placenta/breastmilk
primary organ of metabolism of drugs
liver
define drug metabolism
Breakdown of drugs to convert them to nontoxic substances - makes chemicals less active & more easily excreted
define first pass effect
large percentage of many oral drugs are destroyed and rendered useless during first pass through liver - less of the functional drug makes it to target area
define bioavailability
percentage of drug that reaches systemic circulation
because of the first pass effect, _____ drugs may be given in higher dosages than _____ drugs
PO; IV
example of drugs that do better avoiding the first pass effect i.e. need different absorption site
nitrate drugs
primary organ of excretion
kidneys
define critical concentration
amount of drug needed to cause therapeutic effect
define therapeutic range
not too much to cause toxicity, not too little to have no therapeutic effect
examples of drugs with small therapeutic range
vancomycin, lithium
define loading dose and maintenance dose
higher dose than normally used to “boost” drug to therapeutic levels
once therapeutic levels reached, dose is reduced to maintenance level
example of drug requiring a loading dose
heparin
define peak & trough
highest plasma concentration of drug at certain time
lowest plasma concentration
trough measures…
rate of elimination
trough blood sample needs to be drawn…
just before next dose
define half-life
time it takes for amount of the drug to decrease by ½ of the peak level it previously achieved
A patient takes 100 mg of a drug. 25 mg remains in the blood 6 hours after its peak. What is its half-life? How much will remain after 6 more hours?
3 hours
6.25 mg
how will half-life be affected by liver failure?
increased
which enteric drugs can’t be crushed? why?
enteric-coated - stomach ulcers
sustained release - overdose
routes of admin that introduce drugs directly to stomach
NG tube
gastrostomy
sublingual/buccal drugs should not be…
chewed or swallowed
example of sublingual drug
nitroglycerine
4 types of topical drugs
dermatological preparations
installation & irrigations
inhalations
transdermal patches
installations & irrigations are applied to…
orfices - eyes, nose, ears, vagina, etc
4 things to remember about transdermal patches
Rotate sites
Clean site before & after
Remove old patches before applying new patches
Label patch with date, time, nurse initials
where are ophthalmic drops dropped?
Drops into conjunctival sac of lower lid
where are nasal drops dropped?
Superior concha of ethmoid bone
adults vs children admin ear drops
adult - ear up and out
child - ear down and out
2 things to remember about vaginal suppositories
have them stay in position for 8-10 minutes
offer sanitary pad
position for rectal suppositories
side
for rectal suppositories, apply _____ to finger and med
water soluble lubricant
ID:
___ mL; ____ gauge; _____ inch; keep skin _____; bevel ____; ______ degree angle
1 mL; 27 gauge; 3/8 to 5/8 inch; skin taut; bevel up; 10-15 angle
ID injections produce a…
wheal or bleb
ID example
TB test
SQ:
___ mL; ____ gauge; _____ inch; ______ degree angle; locations include ____
1-3 mL; 23-25 gauge; 1/2 to 5/8 inch; 90 angle if obese or thin; 45 angle if normal; abdomen, back of arm, behind clavicle, thigh
SQ example
heparin, insulin
IM:
___ mL; ____ gauge; _____ inch; ______ degree angle; use ______ motion
1 mL deltoid, 2 mL ventrogluteal; 20-23 gauge; 1 to 1.5 inch; 90 angle; dart motion
IM example
immunizations
IV:
____ gauge
16 gauge trauma patients
18 gauge surgical patients
difference between IV push, bolus, infusion
amount of fluid
