Unit 2 Flashcards
What are the three phases of drug actions?
Drug Administration
Pharmacokinetics
Pharmacodynamics
What is the purpose of the Drug Administration phase?
Drug dosage forms
Routes of administration
Types of Dosage form
Oral (Enteral) Injectable Aerosol/MDI Suppository Sublingeal
Route things to consider
Availability of drug Desired rate of onset/duration of action Safety of route Local/systemic effect is desired Can pt. swallow Stability of agent in GI fluids Amt. of drug needed Convenience
Route of Administration
Enteral Parenteral Transdermal Inhalation Topical
Oral route
cheapest & easiest to absorb in GI tract, then blood stream
Pharmokinetic Phase
Distributed and eliminated in the body based on: Absorption Distribution Metabolism Elimination
Pharacodynamic
Refers to the interaction of the drug molecules with target receptor sites
Three ways drugs produce effects
Key fits lock - causes reaction
Key fits lock - does not cause reaction (broken key blocks receptor site)
Key alters membrane permeability
Three conditions for drugs as a Lock and key
Must reach receptor site
Must be specific to the receptor site
Specifically depends upon chemical structure
Four terms of lock and key
Affinity
Efficacy
Agonist
Antagonist
Affinity
Likeness
Efficacy
Effect
Agonist
Both Affinity and Efficacy
binds to the receptor site and causes an effect or response
Antagonist
Has Affinity not efficacy
binds to the receptor site but causes no response
Type of Drug interactions
Additive
Synergism
Potentiation
Antagonism
Additive
At least two drugs given at the same time and they do what they do
1 + 1 = 2
Synergism
Drugs work together than individually
1 + 1 = 3
Potentiation
Because 2nd drug is there, 1st drug will work better
1 + 0 = 1
Antagonism
Drugs cancel each other out
1 + 1 = 0
Responses to Drug Therapy
Addiction Allergy
Anaphylaxis Carcinogens
Cumulation Desensitization
Dependence Half-life
Paradoxical Effect Potency
Resistance Side Effect
Trachyphylaxis Teratogens
Tolerence
Potency
Refers to the effective dose
Maximum Effect
Greatest response can be produced by a drug.
No further response can be elicited.
Therapeutic Index
Ration of the LD50 and ED50 for a given drug, with ED50 and LD 50 indicating half the test subjects rather than 50% clinical response
ED50
the dose of the drug that produces 50% of the maximal response
LD50
Lethal dose for 50% of the test population
