What is the definition of pharmacology?
Study of use of meds to prevent, diagnose, or cure disease
-substances interacting with body’s system through chemical processess
What is a drug?
Substance that alters physiologic function in an organism
What is the goal of pharmacology?
To deliver a drug to a target tissue in the easiest most sufficient way to achieve therapeutic effect with minimal side effects.
What is the role of PT in pharmacology?
- Review/monitor med list
- Assess how a drug impacts PT participation; fatigue, timing of meds, interactions
- Recognize signs and sx of adverse events and impact has on physical intervention
3 Different systems to classify/name drugs
By Name:
- Chemical name
- Generic name (acetametaphine)
- Trade name (tylenol)
By Therapeutic Classification
ex: decrease blood cholesteral, treat angina
By Pharmacological Classification
ex: lower plasma levels, block Ca channels
What is the role of the FDA?
Facilitate safe available drug effects, improve health of america, and give clear safe instructions for use
- safety and efficacy of all drugs defined
- MUST be demonstrated safe through experiments before approaved
What is the research process of FDA clearance
Preclearance testing: determine effects and safety
Clinical testing:
- Phase 1 with healthy to determine safety
- Phase 2 see if works in patients with disorder
- Phase 3 does it work double blind
Marketing:
-Phase 4 monitor problems in general population
What are the implications of drug approaval?
Cost: to companies and patients
Availability: safe and efficacious drugs in US; other countries just require safety
Potency and Effectiveness of Drug-Receptor Interactions
Drug size/config to binding site:
- lock and key
- electrostatic attraction
- affinity
- selective
Drug classification
- agonist
- partial agonist
- antagonist
- mixed-agonist/antagonist
Receptor interaction important for selectivity and dosage/response relationship
Drug Selectivity
Selective BBlocker
- affects ONLY heart function; no other systems
- can interact with specific receptors on target tissue
Drug Dose-Response
Physiological response to drug dependant on number of receptors bound by the drug
Antagonis vs. Agonist
Drug binds to receptor/initiates change= agonist
-affinity and efficacy
Antagonist binds to receptor but NO change in cell function
- blockers
- only affinity
ex: BBlocker
Drug Safety and Therapeutic Index
Establish therapeutic effect in the margin of saftey without reaching toxic effect
ex: Morphine immediate release and then lower dose for maitenance to maintain therapeutic effect
What are pharmacodynamics?
What the drug does to the body
- desired therapeutic effects
- is med working?
What are pharmacokinetics?
Physiologic response from body after drug intake
-Administration via absorption, metabolism, distribution, and elimination
Pharmacokinetic routes of administration
Enteral
- via GI tract
- oral, sublingual, buccal, and rectal
- buccal/rectal not as effective because have to pass membranes
Parenteral
-via outside GI tract
What are factors affecting absorption?
Drug solubility
Rate of dissolution
Environment of GI tract
Concentration of drug
Circulation to side of absorption
- massage, modalities, heat/cold, exercise
- surface area of tissue absorbing drug
- lungs and intestines
[ALL have impact on effectiveness and adverse effects]
What is first pass metabolism?
Drug going through the system to the liver where it undergoes metabolism
4 Factors that influence drug distribution
- Tissue permebility
- high lipid sollubility
- non-lipi solubility
- blood brain barrier - Blood Flow
- ability to reach organs that are perfused
- brain, kidneys, exercising muscle - Binding to plasma proteins
- reversible bonds to circulating proteins
- ONLY unbound/free drugs can target tissue - Binding to subcellular components
- drugs bound within cells can’t be distributed
- antidepressants
4 Places Drugs can be Stored
- Adipose tissue
- primary site
- due to lipid sollubility of many drugs
- poor perfusion and low metabolic rate
ex: anesthesia drugs - Bone
- heavy metals
- antibiotics - Muscle
- reversible bonds to intracellular structures
- anti-malarials - Organs
- livers and kidneys
- forms reversible bonds with subcellular components
What are possible adverse effects of drug storage?
Local tissue damage
- lead poisonings damage CNS, bone, GI
- metabolism of acetametaphine in unhealthy liver causes liver damage
General Anesthesia
-dosage adjusted to ensure reaches CNS
Redistribution of drugs from storage
- prolonged effects/extended adverse reactions
- anesthesia
What are signs/symptoms of an allergic reaction?
hives/anaphylaxis shock
- low BP
- difficulty breathing
- lose conciousness
- shock
- death