Pharmacodynamics
What the drug does to the body
-3 Mechanisms of action
• Receptor
• Enzyme
• Nonselective Interactions
Enzymes
-most frequently seen in relation to the metabolism of drugs
-act as catalysts in nearly every chemical reaction that takes place in the cells
-drugs can enhance or inhibit the catalytic actions
Nonselective interactions
-drugs chemically alter or physically interfere with cellular structures or there processes
• ex: chemotherapy
Patient-specific plan goals
-cure
-decrease in symptoms
-stopping or slowing the disease process
-preventing disease
-improved quality of life
Types of drug therapy
-acute
• tx active disease & sustain life
-maintenance
• focus on prevention of disease progression
-supplemental
• medication required for normal body function
-palliative
,• any tx program designed to provide symptomatic relief of chronic severe pain
-supportive
• maintains integrity of body functions
-prophylactic
• prevention; immunizations, pre-procedure & postexposure antibiotics
-empiric
• clinical probability of illness that has not yet been diagnosed; administering broad
spectrum antibiotics before culture results
Idiosyncratic effects
unexpected individual responses to medications
Tolerance
declining response to a drug
dependence
physiologic or psychologic need for a substance
NIH: dependence vs addiction
-drug dependence
• a person needs a drug to function normally, abruptly stopping the drug leads to
withdrawal symptoms.
-drug addiction
• the compulsive use of a substance, despite its negative or dangerous effects
drug interactions
• drug-drug
• food-drug
• additive
• synergistic
• antagonistic
• incompatibility
, grapefruit juice decreases the metabolism of a number of drugs, including:
-buspirone
-nefedipine
-statins
what food counters the effect of warfarin
leafy dark greens
-contain vitamin K
antacids reduce effects of some drugs:
(antagonistic interaction)
thyroid replacement hormones
some antibiotics
antagonistic interaction
less than the desired effect of one or both drugs
synergistic interaction
sum total of effect greater than if they were given alone
common synergistic interaction to control hypertension
lisinopril + HCTZ
8 rights of medication administration
1. Right Patient
2. Right Medication
3. Right Dose
4. Right Route
5. Right Time
6. Right Reason
7. Right Response
8. Right Documentation
categories of adverse reactions
-pharmacologic
-allergic
-idiosyncratic
-drug interactions