Therapeutic drug serum levels - ANS narrow range of medication in bloodstream, for desired results; clinical status of patient is appropriate for condition; peak and trough levels (measured by serum blood levels)
nontherapeutic drug serum levels can be either: - ANS undertherapeu...
Therapeutic drug serum levels - ANS narrow range of medication in bloodstream, for
desired results; clinical status of patient is appropriate for condition; peak and trough levels
(measured by serum blood levels)
nontherapeutic drug serum levels can be either: - ANS undertherapeutic or toxic
toxic drug serum levels - ANS greater than therapeutic dose range; increased adverse
effects
under-therapeutic drug serum levels - ANS not enough drug for desired effect; may
contribute to drug-resistant organisms
o Drug Bioavailability - ANS % of active drug absorbed that reaches target tissues
o Drug Bioavailability: determinants - ANS route/form of drug; blood flow; liver/kidney
function; acid-base environment; presence of food, resident bacteria, motility in GI tract;
presence of pain/stress; other drugs
o Oral Absorption (PO): - ANS absorbed from GI tract to body tissues; slower
-Diffuses across cell membrane; assisted by carrier enzymes or proteins; engulfed by cellular
membranes (pinocytosis)
-Easier, more convenient, less expensive; safer than injection; dosage easier to reverse
through intervention in case of accident
o Parenteral Absorption: - ANS by injection; bypass GI tract
Intravenous - ANS absorbed directly into bloodstream
• Rapid onset, since drug is administered directly to bloodstream
• Allows for more direct control of drug level in blood; Gives option of larger fluid volume,
therefore diluting irritating drugs
• Avoids first-pass metabolism
Intramuscular - ANS : absorbed from blood supply of muscles
• Good for poorly soluble drugs, often given in "depot" preparation form and then absorbed over
a long period of time
• Onsets of action depend on route
Subcutaneous: - ANS absorbed through capillaries
,• Same benefits as IM
o Other routes:
Topical - ANS : transdermal
• Delivers medication directly to affected area; decreases likelihood of systemic drug effects
o Other routes: Inhalational - ANS • Provides rapid absorption; drug delivered directly to
lung tissue, where most of these drugs exert their action
o Other routes: Sublingual, buccal - ANS • Absorbed more rapidly from oral mucosa,
leading to a more rapid onset; avoids breakdown of drug by stomach acids; avoids first-pass
metabolism
o Other routes: Rectal (Suppository) - ANS • Relatively rapid absorption, good alternative
when oral route is not available; good for local or systemic drug delivery; usually leads to mixed
first-pass and non-first-pass metabolism
What does the protein-binding ability level of a drug mean? How do albumin levels affect drug
levels in the bloodstream? - ANS o Lower albumin (protein) levels increase drug levels in
the bloodstream, because there are less proteins available to create bound, drug-protein
complexes (inactive drugs, too large to pass through capillary walls of tissues)
4. Why is cytochrome P-450 so important? - ANS o Microsomal enzymes; aid in
metabolism of medications; target lipid soluble (non-polar, lipophilic, fat-loving) drugs, which are
typically difficult to eliminate
What happens when grapefruit juice is taken with a drug that interacts with cytochrome P-450? -
ANS
o Side effect: - ANS : expected averse drug reaction
Undesirable = unexpected (i.e. allergic reaction: hypersensitivity response involving immune
system)
o Adverse reaction: - ANS : any undesirable drug occurrence
Adverse reaction: Idiosyncratic reaction: - ANS occurs unexpectedly in individual patient;
genetically inherited traits
Idiosyncratic reaction:
• Glucose-6-Phosphate Dehydrogenase Deficiency (G6PD): - ANS ): when exposed to
drugs such as sulfonamides, anti-malarials, and aspirin, patients may suffer life-threatening
hemolysis of RBCs; (13-20%) African-American, Kurdish Jewish (50%), Sardinians (14%)
, adverse reaction: Drug-induced teratogenesis - ANS : cause fetal structural defects;
BLACK BOX WARNING
adverse reaction: Mutagenic effects: - ANS permanently changes genetic composition of
living cells
Adverse reactions: carcinogenic reactions - ANS cancer causing
adverse reactions: drug-drug interactions - ANS when two or more drugs come together
and either work together to create a synergistic, antagonistic, or additive effect
o Agonist: - ANS drug binds to the receptor, there is a response
Ex: morphine stimulates opioid receptors
Partial Agonist: - ANS drug binds to receptor, diminished response
o Antagonist: - ANS drug binds to receptor; there is no response. Drug prevents binding of
agonist.
Ex: Narcan (naloxone) displaces morphine
Competitive antagonist: - ANS compete with agonist for binding; if it binds, there is no
effect
Non-competitive antagonist: - ANS combine with different parts of receptor to inactivate it
o Synergists: - ANS drug molecules work with other drug molecules
Produces greater effects than sum of individual drug actions
• 1+1 > 2
Can produce toxic effects
ETOH + tranquilizer = toxicity!
How are drugs metabolized? - ANS o Metabolism = Biotransformation: drugs are
transformed into inactive metabolites, more soluble compound, more potent active metabolite
(ex: conversion of prodrug into active form), or less active metabolite
Primarily in liver; also in kidney, lungs, skin
Liver metabolizes drug from GI tract, reducing bioavailability (< 100%) in first-pass effect; then,
excretes unchanged drug to gallbladder
• Gallbladder bile + drug are reabsorbed into gut
What happens in liver dysfunction? - ANS o Liver dysfunction causes jaundice: metabolic
rate affected
o Renal dysfunction (kidney failure): decreased drug metabolism and excretion
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