Patho I Final Exam (Test 4).docx - NURS 365 Pathophysiology...

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
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