Chap. 5 - pharmacological principles Flashcards
Pharmacology
Study of what drugs do and how they do it
Pharmacokinetics (includes 4 mechanisms)
Study of what the body does to drugs; includes absorption, distribution, metabolism, and excretion
Pharmacodynamics
Study of what drugs do to the body; target sites for drug actions include receptors, ion channels, enzymes, and carrier proteins.
Absorption
Method and rate at which drugs leave the site of administration
Oral meds - where are they typically absorbed and metabolized?
Absorbed in the small intestine
Metabolized in the liver
Distribution
Occurs after the drug leaves the systemic circulation and enters the interstitium and cells
Most psychotropics are lipophilic and protein bound. A patient with low protein (albumin) may become _____ from an increased amount of free drug.
Toxic
Drugs are redistributed in organs according to the _____ and _____ content of the organ.
Fat and protein
Metabolism
Process by which the drug becomes chemically altered in the body.
First-pass metabolism
Process by which the drug is metabolized by P450 enzymes in the intestines and liver before going to the systemic circulation
Elimination
Process by which the drug is removed from the body
Half-life (T1/2)
Time needed to clear 50% of the drug from the plasma
Half-life determines _____ _____
Dosing interval
Steady state
Point at which the amount of drug eliminated between doses is approximately equal to the dose administered
It takes approximately _____ half-lives to achieve a steady state and _____ half-lives to completely eliminate a drug
Five
Five
Drugs are usually administered _____ per half life to achieve steady state
Once
Tegretol, antifungals, rifampin, dilantin, phenobarbital, trileptal, and topamax are common enzyme inducers or inhibitors?
Inducers
Tagamet, erythromycin, biaxin, fluoroquinolones, prozac, and paxil are common enzyme inducers or inhibitors?
Inhibitors
Inducers will _____ the serum level of a substrate drug, causing _____ levels
Decrease
Subtherapeutic
Inhibitors will _____ the serum level of a substrate drug, causing _____ levels
Increase
Toxic
Liver disease affects first-pass metabolism, causing _____ plasma drug levels
Toxic
Kidney disease may _____ levels of renally excreted drugs
Increase
A common drug class that reduces renal clearance is _____
NSAIDS
A common renally excreted psych drug is _____
Lithium
A client taking lithium and Ibuprofen regularly and may find that their lithium level is now _____
Toxic
Because the elderly typically have _____ fat and _____ protein, they are _____ likely to become toxic on psychotropics
Increased fat
Decreased protein
More likely to become toxic
Low protein levels lead to _____ with psychotropics
Toxicity
High fat leads to _____ with psychotropics
Toxicity
Agonism, inverse agonism, partial agonism, and antagonism are four types of _____
Pharmacodynamics
Agonism
Binding to a receptor site to activate a biological response
Antagonism
Binding to a receptor site to NOT cause activation of a biological response
Inverse agonism
Do not bind and do not activate a biological response (the opposite of agonism)
Partial agonism
Do not fully activate the receptors
Excitatory response at an ion channel: channels will _____, allowing _____ and _____ ions to _____ the cell
Channels will open, allowing sodium and calcium to enter the cell
An excitatory response is known as depolarization or repolarization?
Depolarization
Inhibitory response at an ion channel: channels will _____, allowing _____ ions to _____ the cell and _____ ions to _____ the cell.
Channels will open
Chloride enters
Potassium leaves
An inhibitory response is known as depolarization or repolarization?
Repolarization
Some drugs will inhibit enzymes, increasing the availability of neurotransmitter. Name this class of drugs.
MAOIs
Drugs like SSRIs and NDRIs act on…
Reuptake pumps
Potency
Relative dose required to achieve certain effects
Therapeutic index
Relative measure of toxicity or safety of a drug
A drug with a high (think wide) therapeutic index is relatively _____
Safe. Think DPK (high therapeutic index) vs Li+ (low therapeutic index).
A drug with a low (think narrow) therapeutic index is more or less prone to toxicity?
More.
Tolerance
Process of becoming less responsive to a particular drug over time
