1
BSN HESI
BSN HESI 215 DOSAGE CALCULATIONS EXAM (2025/
2026 UPDATE) QUESTIONS & ANSWERS| GRADE A|
100% CORRECT (VERIFIED SOLUTIONS)
What is distribution? - ANS ✓Drug movement from the blood to
the interstitial space of tissues, and from there into cells.
How do drugs leave the vasculature in most tissues? - ANS
✓Through spaces between the cells that compose the capillary
wall.
What is the blood-brain barrier? - ANS ✓The presence of tight
junctions between the cells that compose capillary walls in the
CNS.
What must drugs do to reach the CNS due to the blood-brain
barrier? - ANS ✓Pass through the cells of the capillary wall,
rather than between them.
Do the membranes of the placenta constitute an absolute
barrier to the passage of drugs? - ANS ✓No.
What determines the movement of drugs across the placenta? -
ANS ✓The same factors that determine drug movements
across all other membranes.
What do many drugs bind to in plasma? - ANS ✓Plasma
albumin.
What happens to drug molecules while bound to albumin? -
ANS ✓They cannot leave the vascular system.
BSN HESI
, 2
BSN HESI
What is drug metabolism? - ANS ✓The chemical alteration of
drug structure.
Where does most drug metabolism take place? - ANS ✓In the
liver.
What catalyzes most drug metabolism? - ANS ✓The
cytochrome P450 system of enzymes.
What is the most important consequence of drug metabolism? -
ANS ✓Promotion of renal drug excretion by converting lipid-
soluble drugs into more hydrophilic forms.
What are other consequences of drug metabolism? - ANS
✓Conversion of drugs to less active (or inactive) forms,
conversion of drugs to more active forms, conversion of
prodrugs to their active forms, and conversion of drugs to more
toxic or less toxic forms.
What are drugs that are metabolized by P450 hepatic enzymes
called? - ANS ✓Substrates
What is the effect of drugs that act as P450 inducers on
substrate metabolism? - ANS ✓Increases metabolism
What is the effect of drugs that act as P450 inhibitors on
substrate metabolism? - ANS ✓Decreases metabolism
What is the term for the rapid inactivation of some oral drugs as
they pass through the liver after being absorbed? - ANS ✓First-
pass effect
What is enterohepatic recirculation? - ANS ✓Repeating cycle of
drug metabolism and transport between liver and duodenum
BSN HESI
, 3
BSN HESI
What is the primary organ responsible for drug excretion? -
ANS ✓Kidneys
What are the three steps of renal drug excretion? - ANS
✓Glomerular filtration, passive tubular reabsorption, active
tubular secretion
Why can't highly lipid soluble drugs be excreted by the
kidneys? - ANS ✓They undergo extensive passive reabsorption
back into the blood
What is the risk of drugs being excreted into breast milk? - ANS
✓Threat to nursing infant
What is the correlation between plasma drug level and
therapeutic/toxic effects? - ANS ✓Direct correlation
What is the minimum effective concentration (MEC)? - ANS
✓Plasma drug level below which therapeutic effects will not
occur
What is the therapeutic range of a drug? - ANS ✓Range
between MEC and toxic concentration
What is therapeutic range? - ANS ✓Range of drug dose that is
effective and safe
What is the difference between drugs with wide and narrow
therapeutic range? - ANS ✓Wide range is easy to use safely,
narrow range is difficult
What is half-life of a drug? - ANS ✓Time for drug amount in
body to decline by 50%
BSN HESI
BSN HESI
BSN HESI 215 DOSAGE CALCULATIONS EXAM (2025/
2026 UPDATE) QUESTIONS & ANSWERS| GRADE A|
100% CORRECT (VERIFIED SOLUTIONS)
What is distribution? - ANS ✓Drug movement from the blood to
the interstitial space of tissues, and from there into cells.
How do drugs leave the vasculature in most tissues? - ANS
✓Through spaces between the cells that compose the capillary
wall.
What is the blood-brain barrier? - ANS ✓The presence of tight
junctions between the cells that compose capillary walls in the
CNS.
What must drugs do to reach the CNS due to the blood-brain
barrier? - ANS ✓Pass through the cells of the capillary wall,
rather than between them.
Do the membranes of the placenta constitute an absolute
barrier to the passage of drugs? - ANS ✓No.
What determines the movement of drugs across the placenta? -
ANS ✓The same factors that determine drug movements
across all other membranes.
What do many drugs bind to in plasma? - ANS ✓Plasma
albumin.
What happens to drug molecules while bound to albumin? -
ANS ✓They cannot leave the vascular system.
BSN HESI
, 2
BSN HESI
What is drug metabolism? - ANS ✓The chemical alteration of
drug structure.
Where does most drug metabolism take place? - ANS ✓In the
liver.
What catalyzes most drug metabolism? - ANS ✓The
cytochrome P450 system of enzymes.
What is the most important consequence of drug metabolism? -
ANS ✓Promotion of renal drug excretion by converting lipid-
soluble drugs into more hydrophilic forms.
What are other consequences of drug metabolism? - ANS
✓Conversion of drugs to less active (or inactive) forms,
conversion of drugs to more active forms, conversion of
prodrugs to their active forms, and conversion of drugs to more
toxic or less toxic forms.
What are drugs that are metabolized by P450 hepatic enzymes
called? - ANS ✓Substrates
What is the effect of drugs that act as P450 inducers on
substrate metabolism? - ANS ✓Increases metabolism
What is the effect of drugs that act as P450 inhibitors on
substrate metabolism? - ANS ✓Decreases metabolism
What is the term for the rapid inactivation of some oral drugs as
they pass through the liver after being absorbed? - ANS ✓First-
pass effect
What is enterohepatic recirculation? - ANS ✓Repeating cycle of
drug metabolism and transport between liver and duodenum
BSN HESI
, 3
BSN HESI
What is the primary organ responsible for drug excretion? -
ANS ✓Kidneys
What are the three steps of renal drug excretion? - ANS
✓Glomerular filtration, passive tubular reabsorption, active
tubular secretion
Why can't highly lipid soluble drugs be excreted by the
kidneys? - ANS ✓They undergo extensive passive reabsorption
back into the blood
What is the risk of drugs being excreted into breast milk? - ANS
✓Threat to nursing infant
What is the correlation between plasma drug level and
therapeutic/toxic effects? - ANS ✓Direct correlation
What is the minimum effective concentration (MEC)? - ANS
✓Plasma drug level below which therapeutic effects will not
occur
What is the therapeutic range of a drug? - ANS ✓Range
between MEC and toxic concentration
What is therapeutic range? - ANS ✓Range of drug dose that is
effective and safe
What is the difference between drugs with wide and narrow
therapeutic range? - ANS ✓Wide range is easy to use safely,
narrow range is difficult
What is half-life of a drug? - ANS ✓Time for drug amount in
body to decline by 50%
BSN HESI
