Pharmacological Principles Flashcards
Absorption Definition
Transmission from location of administrations bloodstream
Rate of Absorption
How soon medication will take effect
Amount of Absorption
How much the body absorbs determines intensity of effects
Route of Administration
Affects the rate and amount of absorption
Oral- barriers of absorption
Must pass through the layer of epithelial cells of GO tract
Oral- absorption pattern
- Varies due to:
- stability and solubility
- GI pH
- presents of food
- other meds
- forms of meds
Sublingual Barriers
Swallowing before dissolution allows gastric pH to inactivate medication
Sublingual Absorption pattern
Quick- highly vascular membranes
Rectal/Vaginal Barriers of Absorption
Presence of stool or infectious material limits tissue contact
Vaginal/Rectal Absorption Pattern
Easy Absorption
Inhalation Barriers to Absorption
Inspiratory effort
Topical Absorption Barriers
Close proximity to cells
Inhalation Absorption Pattern
Rapid through alveolar capillary
TopicL Absorption Pattern
Slow-gradual
Primarily effects local
Sub-Q - IM Barriers to Absorption
No significant barriers
SubQ/IM Absorption Pattern
- Highly soluble in water
- High blood perfusion sites- rapid absorption
- Low blood perfusion- low absorption
IV Barriers to Absorption
No barriers
IV Absorption Pattern
Immediate- directly into blood stream
Complete- reaches blood entirely
Distribution
Transportation of medication to sites of action by bodily fluids
Factors Affecting Distribution
- Circulation: low circulation delays distribution
- Permeability of cell: medication must be able to pass through
- Plasma Protein Binding: ability of medication binding to a protein affects how much medication will leave and travel to target tissue
Metabolism
Changes medication into less active or inactive forms
*primarily in liver
Factors Affecting Metabolism
Age
Increase in medication-metabolizing enzyme: metabolizes sooner, therefore higher dose required
First-pass effect: liver inactivated on first pass, therefore requires alternate route
Similar metabolic pathways: leads to medication accumulation
Nutritional status
Metabolism Outcome
Increased renal excretion
Inactivate of medication
Increased therapeutic effect
Activation of pro-meds
Decreased toxicity: active form becomes inactive
Increased toxicity: inactive forms become active
Excretion
Elimination of medication
Primarily in kidneys
Watch BUN & Craatine w/kidney dysfunction: increase duration and Intensity
Therapeutic Range
When the medication is effective and not toxic
Half-Life
Time of medication in body to drop by 50%
Short half-life
Leave body quick
4-8 hours
Long half-life
Leave body slowly
24+ hours
Risk accumulation and toxicity
Pharmacodynamics
Interactions between medication and target
Agonists
Bind to or mimic receptor activity
Antagonists
Block receptor activity
Partial agonists
Agonists and antagonists
