Class 3 - Principles of Pharmacology Flashcards
pharmacokinetics
the process of a drug movement through the body. all drugs go through the 4 stages
pharmacodynamics
the study of the effect of a drug on cells, and the drugs mechanism of action
what are the 4 stages of pharmacokinetics
absorption, distribution, metabolism, excretion
absorption
process of moving a substance from its site of administration, across the body membranes to the bloodstream.
depends on size, lipid solubility, degree of ionization, and interaction with food and other drugs
the more rapid the absorption, the faster the onset of drug action
acids will absorb in acids, bases will absorb in bases
first past effect
drug goes to liver after taking orally
bioavailability
the amount of drug that reaches the target.
what are factors that could affect drug absorption?
taking other drugs, what’s in your gut, certain acidic and non-acidic environments
distribution
describes how drugs are transported through the body to receptor sites. how a drug becomes available to body fluids and body tissues.
what influences distribution?
blood flow, the drugs solubility, the drugs affinity to the tissue, protein binding effect, dehydration, blood viscosity, placental barriers
what is the protein binding effect?
some drugs bind to a protein so they need to be taken with a meal
metabolism
also known as biotransformation. process of chemically converting a drug to a form that is usually removed from the body more easily. makes it more likely to be excreted.
what is the primary site of metabolism?
the liver, kidneys are secondary
what factors might affect metabolism?
hepatitis, diseases that attack or damage the liver, cirrhosis (liver scaring)
excretion
remove drug metabolites from the body and only sometimes the actual drug itself
where are drugs excreted?
usually the kidneys but may also be excreted by the lungs or glands, or into bile (sweat, feces, urine, breast milk)
half life
length of time for 50% of a drug to be absorbed. by knowing the half life we can determine dosing schedules
what can affect the half life?
metabolism and elimination.
therapeutic range
drug concentration between the minimal effective concentration and toxic concentration
agonist
drugs that produces a response the same as the endogenous substances
antagonist
drug that prevents a response from endogenous chemical
idiosyncratic effect
individualized, unpredictable and unexplained drug reactions
adverse effect
undesirable and potentially harmful action caused by the administration of a medication
partial agonist
medication that produces a weaker, or less effective response than an agonist
polypharmacy
the taking of multiple drugs
synergistic effect
the combined effect of two different drugs is greater than the sum of the effect of each drug taken alone
tolerance
adapting to a drug over a period of time and subsequently requiring higher doses to achieve the same effect
physical dependance
experiencing unpleasant withdrawal symptoms when a substance is discontinued
allergic reaction
acquired, immune system response to a foreign substance
anaphylaxis
extreme hypersensitivity to an antigen and may lead to life threatening shock if untreated
dissolution
the first phase of drug action for oral medication. the drug goes into solution so that it can cross the biological membrane. when the drug is administered by injection or topically, there is no pharmaceutic phase
what are the stages of dissolution?
tablets-disintegration-dissolution
onset of action
the time it takes to reach the minimum effective concentration after drug administration
what is peak action
when the drug reaches its highest blood or plasma concentration
duration of action
the length of time the drug has a pharmacologic effect
trough
lowest level of drug before administering another dose
drug receptor theory
the activity of many drugs is determined by the availability of the drug to bind to a specific receptor. the better the drug fits at the receptor store, the more biologically active it is. most receptors are found on cell membranes
cumulative effect
when the effects of a drug increase due to retention of the drug in the body
additive effect
two of the same drugs with similar action are taken for a doubled effect
side effect
predictable, less serious drug effect
enteric-coated
a tablet is coated with a substance that prevents the medication from being released until it reaches the small intestine, where it can then be absorbed
parenteral administration
injection or infusion. common types of injection are intravenous (into a vein), subcutaneous (under the skin), and intramuscular. the most common infusion is intravenous
what is cirrhosis
liver scarring
therapeutic response
onset of action, peak action, duration of action, therapeutic range
what is another name for metabolism
biotransformation
what determines the route of administration?
the form the medication is in
topical
hormones that influence the activities of a certain gland
nephrotoxicity
toxicity of kidneys
IM
intramuscular
