Facts Flashcards
(32 cards)
3 most important properties of drugs
effectiveness - has to do what it is supposed to do
safety - there is no completely safe drug
selectivity - one that elicits only desired effects - there is no such thing (all have side effects)
other desired properties
reversibility
predictability
ease of administration
freedom from drug interactions
low cost
chemical stability
possession of a simple generic name
reversibility
drug actions to subside within an appropriate time (aside from things like antibiotics)
predictability
knowing how someone will respond - not guaranteed because everyone is different
ease of administration
has two benefits
1 it can enhance patient adherence
2 it can decrease risk. patient more likely to stick to dosing schedule (1 dose per day rather than multiple)
freedom from drug interactions
not have bad interactions when taken with other drugs
low cost
drugs can be very expensive
chemical stability
an ideal drug would retain its activity indefinitely instead of expiring after time
possession of a simple generic name
generic names are complex. an ideal drug would have one that is easy to remember
factors that determine the intensity of a drug response
administration - dosage, route, timing, adherence, errors
pharmacokinetics - absorption, distribution, metabolism, excretion
pharmacodynamics - drug-receptor interaction, patient’s functional state, placebo effects
5 rights
right..
1 drug
2 patient
3 dose
4 route
5 time
drug absorption affecting factors
rate of dissolution
absorbing surface
blood flow - high blood flow = high absorption
lipid solubility of drug - high solubility = faster absorption
pH partitioning - acidic drugs - alkaline side of membrane, basic drugs - acidic side of membrane
parenteral meds benefits and problems
benefits:
no barriers
rapid onset
can give large amounts of fluids
circulated quickly
problems:
cost, convenience
not reversible
infection, embolism
must be water soluble to be injected
intramuscular (IM) absorption rate
10-30 minutes
subcutaneous (SQ) absorption rate
blood flow not as good as IM so may be slower
enteral (by mouth via GI) barriers to absorption
1 epithelial cells of GI tract lining (biggest barrier)
2 endothelial cells of capillary wall
factors affecting enteral (by mouth) absorption
solubility
GI pH
gastric emptying
stomach contents
other drugs
drug coating
disadvantages of enteral (by mouth)
variable absorption
inactivation by food, other drugs, gastric acidity, liver (first pass)
patient must be awake, alert
GI upset
other routes of administration
topical - skin, eyes, ears, nose, mouth, rectum, vagina
inhaled
rectal suppositories
vaginal suppositories
direct injection - joints, heart, CNS
distribution of drug affected by
1 blood flow
2 ability to exit the vascular system
3 ability to enter cells
drugs that are/have _______ can cross the blood brain barrier
lipid soluble
have a transport system
an important consequence of drug-protein binding
restriction of drug distribution
albumin (most important binding protein) is too large to get through capillary wall, so it stays in the blood stream
drugs that bind albumin cannot leave blood stream either until bond is broken
most drug metabolism takes place in
the liver
results of drug metabolism
accelerated renal excretion of drugs
drug inactivation
increased therapeutic action
activation of prodrugs - inactive as administered and is converted into active form via metabolism
increased toxicity
decreased toxicity
