NURS 365: Pathophysiology and Pharmacology Final
Exam Study GUide
Comprehensive content- 30 questions + Pulmonary content- 35 questions = 65 questions
Introduction to Pharmacology
-2 questions
Purpose of drug therapy
●
Three MOST important properties of an ideal drug
○
Effectiveness
→ has to do what it is supposed to do
○
Safety
→ no completely safe drugs, side effects has to be a balance
○
Selectivity
→ would produce ONLY the desired effect
Pharmacokinetics
●
Absorption
→
movement
of drug
from
site of administration
into
bloodstream
○
Affecting factors:
■
Rate of dissolution
■
Absorbing surface
■
Blood flow
■
Stomach contents
■
Other drugs
■
Drug coatings/compound
■
pH partitioning
■
Lipid solubility of drug:
lipid soluble → pass
through membrane→ be
absorbed
○
Parenteral (anything but oral/not through GI tract)
■
Intravenous
(IV) → no barriers to absorption, directly in blood stream
●
Benefits:
○
Rapid onset
○
Can give large amounts of fluid
○
Dispersed and circulated quickly
●
Problems:
○
Cost, convenience
○
Not reversible
○
Infection, embolism
○
Drugs have to be
water soluble
to be injected
■
Intramuscular
(IM)
●
Absorbed through capillary wall
●
Absorption determined by blood flow + drug solubility (~ rapid 10-30
min)
■
Subcutaneous
(SubQ) → similar to IM
●
Blood flow not as good as IM, absorption may be slower
○
Enteral (by mouth)
■
Oral
(PO) → via the GI tract
●
Barriers to absorption:
○
Epithelial cells of GI tract lining → very tightly packed
○
Endothelial cells of capillary walls → opening between cells
●
Factors affecting absorption:
○
Solubility → needs to be dissolved, not ionized
○
GI pH, gastric emptying, stomach contents, other drugs,
coatings
●
Disadvantages:
○
Variable absorption → every person will be different
○
Inactivation by food, other drugs, gastric acidity, liver
○
Patient must be awake, alert, and needs to swallow by
themselves
○
GI upset
●
Distribution
→
movement
of drugs
through
the body
○
Affected by: blood flow, ability to exit vascular system, ability to enter cells
■
Exit affected by: protein binding (more drug bound to protein, less available
to be distributed tissues) and barriers
●
Barriers:
○
Blood-brain barrier → tight junctions between cells
■
have to be lipid soluble
○
Placental → not necessarily a barrier, not a junction
■
Lipid soluble, nonionized drugs can pass through
●
Metabolism
→
alteration
of the drug, enzymes
○
Liver and kidneys
○
Results of metabolism:
■
Accelerated renal excretion of drugs not lipid soluble, makes more water
soluble
■
Drug inactivation (convert to inactive form)
■
Increased therapeutic action
■
Increased or decreased toxicity
○
First pass effect
→ rapid hepatic inactivation of certain oral drugs
■
GI tract → capillary → venous system → liver
■
Won't get 100% of drug into the system*
●
may need to increase dosage to account for this
●
Excretion
→ drug
elimination
, removal of drug from the body
○
Bile and urine
○
Glomerular filtration
→ moves drugs from blood into renal tubule
○
Passive tubular reabsorption
→ lipid soluble will move back into blood
■
