Flashcards
pharm 2060 MT 1 - 2
Cards in this deck (35)
- 1pharmacokineticsthe study of drug movement in the body
what the body does to the drug - 2absorptionthe movement of the drug from the site of administration into the blood
det how quickly the drug effect will occur
the amt of drug absorption determines how intense the effect of the drug will be - 3factors affecting absorption (5)rate of dissolution
SA
blood flow
lipid solubility
pH partitioning
activity of drug transport proteins - 4rate of dissolutionhow fast it dissolves in solution
drugs must dissolve before they can be absorbed - 5surface areaie stomach has rugae folds
itnestine has villi
villi that line the intestine make the SA very large - 6blood flowdrug absorption is fastest in areas w high blood flow b/c high BF maintains conc grad
exercise increases blood flow --> can inc drug absorption
blood flow is decreased in heart failure, severe hypotension, hypothermia and circulatory shock - 7lipid solubilitycan cross PM but hydrophilic can't
- 8pH partitioningdrug absorption is greater when there's a difference between the pH at the site of administration and the blood such that the drug is ionized in the blood
- 9activity of drug transport proteinuptake drug transporters increase the absorption of drugs
efflux drug transporters decrease the absorption of drugs - 108 major routes of administrationsoral
sublingual
rectal
intravenous
subcutaneous
intramuscular
pulmonary - 11enteralroutes of administration that involve the GI tract: oral, rectal
- 12parenteralroutes of administration that do not involve the GI tract: intravenous, intramuscular, subcutaneous
- 13other routes of administration (other than enteral, parenteral)sublingual, transdermal, pulmonary
- 14intestine v stomach for oral absorptionintestine has larger SA so drug absorption greater in intestine
even weak acids b/c the stomach (stomach = acidic) is covered in a thick layer of mucous - 15pharmaceutical phaseoccurs after the patient swallows a tablet
involves the disintegration of the tablet and the dissolution of the drug
if drug does not completely disintegrate, or does not go into soln, absorption is reduced - 16gastric emptyinggastric emptying is the movement of stomach contents into the intestine
things that inc the rate of gastric emptying also inc the rate of drug absorption - 17factors that increase gastric emptyingempty stomach
cold water
lay down right side
high osmolality feeding (tube feed)
taking prokinetic drug (inc GI motility) - 18factors that decrease gastric emptyinghigh fat meal
heavy exercise
lying down on left side
taking a drug that inhibits the vagus nerve (anticholinergic) - 19enteric coatingspecial coating that prevents drug dissolution in the acidic environment of the stomach
will dissolve in alkaline duodenum - 20bioavailabilityfraction of a dose of drug that reaches the systemic circulation unchanged -- influenced by: drug formulation, route of administration, degree of metabolism
- 21order of bioavailabilityaqueous soln is most
syrup
suspension
chewable tablet
granules
capsules
compressed tablet
enteric coated tablets
time release capsules - 22sublingualplacing drugs under tongue --> absorbed across the oral mucosa
venous drainage from oral mucosa to the superior vena cava --> heart
these avoid first pass metabolism thru the liver ***
in order to be absorbed, drugs must be lipophilic and uncharged - 23transdermalproblem b/c not all drugs penetrate hte skin
drugs must be lipophilic enough to penetrate the skin, but hydrophilic enough to dissolve into the extracellular fluid
ideal transdermal preparations have some degree of lipophilicity and some degree of hydrophilicty and are usually small - 24transdermal preparationsusually: patches, ointments, sprays, lotions
transdermal administration provides constant plasma drug levels w minimal peaks and troughs
tolerance may develop unless drug-free periods are enforced --> remove for 6-10 hours a day - 25factors affecting transdermal absorptionthickness of skin
hydration (more = better)
hair follicles (more = better)
application area
integrity of the barrier (psoriasis, burned inc absorption) - 26rectaluseful when unconscious or vomitting
50% bypasses liver
inserted as a suppository --> dissolves and drug crosses rectal mucosa - 27intravenousdrug is injected directly into a peripheral vein
most commonly used veins: back of hand, median cubital vein @ elbow
can be bolus or IV Drip
IV bolus: single dose over short time
IV drip: continuous infusion over long time (usually diluted) - 28advantages of intravenousno barriers to absorption, bioavailability 100%
allows precise control of the drug dosage and duration of action
allows administration of poorly soluble drugs that must be diluted in a large volume
allows injection of drugs that are irritants (ie chemo) --> can be injected slowly so they are diluted in the blood - 29disadvantages of intravenousexpensive, invasive, inconvenient
drug can't be removed once injected
risk of infection and fluid overload
risk of injecting wrong formulation (IM instead of IV) - 30subcutaenousdrug is injected beneath the skin into the subcutaneous tissue
only barrier is the capillary wall
irritant drugs must not be injected subcutaneously as this will cause severe pain and tissue sloughing
primary det of rate of absorption: blood flow, water solubility - 31intramusculardrug injected directly into muscle tissue
absorption is det by the ability of the drug to pass thru fenestrations in the capillary wall
primary et of rate of absorp: blood flow, water solubility - 32advantages of intramuscularcan be used for poorly soluble drugs
can use to administer depot preparations (where it is slowly absorbed over time) - 33disadvantages of intramuscularpain or discomfort
may cause local tissue or nerve damage if the injection is done improperly - 34how blood flow affects intramuscular absorptionblood flow: diff dep on which muscle is used for injection
deltoid > vastus lateralis > gluteal
exercise increases blood flow --> may inc absorption for IM drugs
blood flow may be dec in heart failure, severe hypotension and hypothermia - 35pulmonarygaseous and volatile drugs can be inhaled and absorbed into the blood thru the pulmonary epithelium
absorption is v rapid due to large surface area of lung
if pulmonary disease, drug is delivered to its site of action which is a major advantage
drugs such as general anaesthetics used in surgery are also often administered by the pulmonary route of administration
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- Flashcards on pharm 2060 MT 1 - 2 , created by Mary Nguyen on 10/02/2016.
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