4. What about medicine?
Think of the last time you were sick.
You most likely took some sort of medication that
eventually helped you feel well again.
But what happened to the medicine once it completed
its task?
It must be excreted!!!
5. Pharmacology- study of drugs and their
interactions with living systems.
Pharmacokinetics- drug movement
1. Absorption
Route from administration site
to the bloodstream
IV, Injection, Oral, or Topical
2. Distribution
Bloodstream to the site of action
Fig. 1-Pharmacokinetics: Absorption,
distribution, metabolism, and elimination.
6. Pharmacokinetics
3. Metabolism
The breakdown of chemical
structure by the liver
4. Excretion
The elimination of a
medication from the
body primarily through
the kidneys.
Fig. 2-Absorption, distribution, metabolism, and
excretion in the human body.
7. Kidney Anatomy
Fig. 4 A single nephron unit.Fig. 3 Longitudinal section of the kidney
8. Glomerular Filtration
Begins at the glomerulus
Consists of a capillary
network surrounded by
Bowman's capsule
Small pores perforate the
capillary walls
Drugs are forced
through these pores
This process moves
drugs from the blood
into the tubular urine. Fig. 5-Renal corpuscle
9. Passive Tubular Reabsorption
Blood vessels to the
glomerulus meet up with
the renal distal tubule.
Here, concentration of
drugs in the blood are lower
than drugs in the tubule.
This concentration gradient
acts as a driving force to
move drugs from the tubule
back into the blood
(reabsorption).
Fig. 6-Glomerular capsule.
http://kvhs.nbed.nb.ca/gallant/biology/nephron_structu
re.html
10. Active Tubular Secretion
Drugs are pumped from the
blood to tubular urine via active
transport systems.
An area of lower concentration
toward an area of higher
concentration.
Requires energy
Tubular cells contain P-
glycoprotein in their
membranes, which pump drugs
into urine.
Fig. 7-Renal drug xcretion.
12. References
Lehne, R. A. (2013). Pharmacology for nursing care. 8th Ed. St.
Louis, Mo: Elsevier/Saunders.
Lewis, Sharon. Medical-Surgical Nursing: Assessment and
Management of Clinical Problems, 8th Edition. Mosby, 2011.
<vbk:9780323065801>.
Urinary System. (n.d.). Retrieved August 30, 2013, from
http://legacy.owensboro.kctcs.edu/gcaplan/anat2/notes/A
PII Notes3%20urinary%20system.htm
Wissman, J., Knippa, A., Lawler, K. M., Stacy, B. L., & Assessment
Technologies Institute. (2008). Pharmacology for nursing.
Overland Park, KS: Assessment Technologies Institute.