Principles of Pharmacology Flashcards
the legal right to prescribe drugs
prescriptive authority
prescriptive authority for APRNs is determined by ____
state of residence/practice
Schedule ___ - ____ controlled substances are included in TN APRN prescriptive authority
II-V
TN Requirement for controlled substances prescription by APRNs
DEA #
Rank of Quality of Evidence
- Systemic Reviews
- Critically-Appraised Topics/Articles
- RCTs
- Cohort Studies
- Case-Controlled Studies, Case Series, Reports
- Background Info/Expert Opinion
how the drug moves through the body and what the body does to the drug
pharmacokinetics
the progress of a drug from administration through the time it passes to the tissues until it becomes available for use by the body
absorption
What determines route of the drug?
absorption and distribution
Factors that affect ________:
route of administration
amount of blood flow
drug form
absorption
_____ and _____ are the fastest oral administrations
buccal and sublingual
rate and extent to which a drug enters the circulation and gains access to target tissue
● When a drug is dissolved, doesn’t survive liver passage, a fraction gets to the bloodstream → need for higher doses
● “What makes it to the bloodstream”
Bioavailability
the speed of bloodstream entry affects max blood level after admin; rapid absorption increases this
peak blood level
rapid absorption causes ______ peak blood level so APRN needs to consider this with ______ drugs
increases; IV push drugs
____ membranes are easier for drugs to cross and cross the blood-brain barrier
lipid
whether or not a drug binds and becomes inactive; drug action occurs through free, unbound drug
protein-binding
(many in the liver) help normalize concentrations throughout the body, altered by disease states; in the plasma and encourages drug retention in systemic circulation→ appearance of high drug levels but it is not at the active site; binding is the basis for several drug interactions; cannot interact with their receptor; if strongly bound a small change in binding can → significant effects
plasma proteins
hypothetical value that reflects the volume in which a drug would need to be dissolved to explain the relationship between dosage and blood levels.Tells where a drug might be distributed
volume distribution
Drug that produces an effect similar to those produced by naturally occurring hormones, neurotransmitters, and other substances. Drug that interacts with receptors; has an attraction/affinity for receptor and stimulates it. A chemical that binds to a receptor andsdf activates the receptor to produce a biological response. Intrinsic activity: drug’s ability to initiate a response after receptor binding
agonists
type of agonist that don’t need all available receptors to illicit max response, spare receptors are left over, not needed
full agonist
bind and activate a given receptor, but have only partial efficacy at the receptor relative to a full agonist, even at maximal receptor occupancy.; between agonist/antagonist; max response < full agonist
partial agonist
3 ways drugs pass across membranes:
- Channels/Pores
- Transport Systems (p-glycoproteins)
- Direct Penetration
Transmembrane protein that transports a wide variety of drugs out of cells
P-Glycoprotein
For most drugs, movement throughout the body is dependent on the drug’s ability to ________
directly penetrate membranes
to directly penetrate membranes, a drug must be _____
lipophilic (lipid soluble)
Molecules that contain at least one atom of nitrogen and carry a positive charge at all times
Quaternary ammonium compounds
Acid is a proton donor: Tends to ionize in basic (alkaline) media
Base is a proton acceptor: Tends to ionize in acidic media
pH-dependent ionization
Acidic drugs accumulate on the alkaline side
Basic drugs accumulate on the acidic side
Ion trapping (pH partitioning)
Factors affecting \_\_\_\_\_\_: Rate of dissolution Surface area Blood flow Lipid solubility pH partitioning
absorption
Factors determining _____:
Blood flow to tissues
Exiting the vascular system
Entering cells
Distribution
drug has an affinity for receptor but displays little or no intrinsic activity, prevents the response from occurring. Chemical that binds to a receptor & blocks the action of the agonist
antagonist
type of antagonist that competes with agonist for receptor sites; binds reversibly to the receptor site; large agonist doses can overcome antagonist effect; agonist cannot bind to the receptor because the competitive antagonist is bound to the binding site where the agonist would have binded to.
competitive antagonist
type of antagonist that binds to receptor and blocks agonist effects; can’t reverse with large agonist dose.
Bind to the receptor somewhere else than the agonist binding site
noncompetitive antagonist
type of antagonist that binds directly to the agonist and prevents it from binding to the receptor.
Ex; heparin would be an agonist that is a blood thinner, and protamine binds directly to heparin that prevents it from working.
chemical antagonist
biotransformation, refers to body’s ability to change drug from dosage form to ↑water soluble form that can be excreted; several ways metabolized- into inactive metabolites (products) that are then excreted, conversion to active metabolites that can exert their own pharm action; prodrugs don’t become active until metabolized; most drugs metabolized by liver
metabolism
Factors affecting \_\_\_\_\_\_: ↓ by certain diseases genetics environment development/age
metabolism
“family” of enzymes, each responsible for single type of metabolic reaction; most thoroughly studied drug metabolism reaction; catalyzes metabolism of a large variety of meds
CYP450
drugs that cause CYP450 to induce metabolism
inducers
Example of _______:
Tegetrol induces the CYP450 system which ↑ Metabolism of estrogen, which ↓ blood levels of estrogen & this could increase chance of pregnancy due to ↓ in contraceptive effect.
Inducer drug
drugs that cause CYP450 to inhibit metabolism
inhibitors
Example of ______:
Erythromycin inhibits the CYP450 system which reduces the metabolism of drugs. If you have decreased metabolism than drugs can build up in the system causing toxicity.
Inhibitor drug
Effect when _______:
competition occurs when two different drugs are metabolized by the same enzyme; often the enzyme can metabolize both drugs, sometimes one drug will be preferentially metabolized, delaying the metabolism and extending the half life of the competing drug
2 drugs use the same pathway
drugs induce CYP450 by causing an increased amount of CYP450 enzymes; this results in increased metabolism of the drug, therefore, decreased pharmacological effect of the drug; “enzyme increasers”
Enzyme Induction
substances that block the enzyme system which increases the pharmacological activity of the drug and other drugs. Grapefruit juice prevents enzymes in GI tract from breaking down other drugs and so other drugs end up having increased actions
Other EX: depakote, diflucan, tagamet, alcohol/binge drinking, cipro, flagyl, prilosec,sulfonamides, erythromycin
Enzyme Inhibitor
drugs that can be administered as inactive drugs; don’t become active until they’re metabolized
prodrug
drug that increases metabolism and the need for an increased dosage of the drug to be effective.
ultra-rapid metabolizer
extra gain function alleles produce lots of enzyme to metabolize the drug → drug being gone quickly → ↓ area under the curve (AUC), ↓side effects, ↓ possibility of cure
active drugs
extra gain function alleles produce lots of enzyme to metabolize the drug → drug active quickly
prodrug
normal functioning alleles produce enzymes to metabolize drug; active → drug gone; prodrug→ drug active
extensive metabolizer
: one functioning allele, one loss of function allele. May lead to excessive accumulation of the metabolite (also resulting in toxic levels)
intermediate metabolizer
can cause accumulation of the drug and potentially toxic levels and therefore, the need for a reduced dosage.
○ Active→ two loss of functioning alleles produce little of no enzyme to metabolize drug → drug keeps hanging out → ↑AUC, ↑side effects, ↑possibility of cure, ↑risk for toxicity
○ Prodrug→ may fail to become active; ↓side effects because it lacks action
poor/intermediate (slow) metabolizer
metabolism by the liver following oral administration; liver contains high amounts of drug metabolizing enzymes and because it is the first organ encountered by drugs once absorbed from the GI tract
Hepatic First-Pass