Drug actions Flashcards
(42 cards)
The nurse must have knowledge of the pharmacokinetic and pharmacodynamic phases of drug action to:
-adequately assess, plan, intervene and evaluate drug effects.
Processes of drug absorption:
- passive
- active
- pinocytosis
Passive diffusion (absorption)
O
Active diffusion (absorption)
o
Pinocytosis (absorption)
o
First-pass effect:
in the liver
Bioavailability (Affected by)
- drug form
- route of administration
- GI mucosa and motility
- food and drugs
- changes in liver metabolism caused by liver dysfunction or inadequate hepatic blood flow
IV drugs
100% of drug is in systemic circulation.
30% may be bound to protein
70% to be used up
Low
O
Moderate
o
High
o
Protein binding
- drugs are distributed in the plasma many are bound to varying degrees with protein (albumin)
- portion that is bound is inactive
- not available to receptors
- drugs compete for protein sites
Blood brain barrier
highly lipid soluble drugs cross
Placenta
lipid soluble and lipid insoluble cross
Metabolism (Bio transformation)
-liver=primary site
Half-life
- time it takes for one half of the drug concentration to be eliminated affect half-life.
- metabolism and elimination affect half-life.
excretion (elimination)
- kidney: primary site
- creatinine clearance
- urine ph affects drugs excretion
Sodium bicarbonate
neutralizes acids (respiratory/cardiac arrest)
Pharmacodynamics
-study of way drugs affect the body
(Drug concentration and its effect of the body)
-primary effect is desirable
-secondary effect may be desirable or undesirable.
Dose response and maximal efficacy
- every medication has a maximum drug effect.
- Relationship between minimum amount vs maximum amount of the drug needed to produce the desired response.
Onset
-time it takes to reach the minimum effective concentration.
Peak
-highest blood concentration
Duration of action
-length of time a drug has a pharmacological effect
Receptor theory
- how drugs get used up.
- how they affect the body.
