9/23b Pharmacology (Biomedical Sciences) Flashcards
• To understand the basic principles of pharmacology so as to apply them as a clinician • To understand the fundamental concepts of pharmacodynamics, including mechanism of action and dose-responsive curve To understand the stages of pharmokinetics as the drug is processed in the body and factors affecting pharmokinetics
Drug Nomenclature
- Chemical - the chemical structure of the drug
- Generic - abbreviated version of the chemical name
- Trade Names - Motrin = NSAID = Ibuprofen = Isobutyl propanoic phenolic acid
what is the process that takes a drug to be ready to be sold on the market?
- approval from FDA
- regulation
- animal trials and human trials that last up to 20 years
- data is sent to FDA after completed
- the whole trial needs to be safe and effective - classification
- prescription (Rx) vs over the counter (OTC)
- often Rx drugs can change to be over the counter drugs as more data is stored
Are PTs allowed to prescribe drugs?
- NO, except for PTs in the military (they can prescribe analgesics)
- it is important to use information about the drugs to educate your patients and understand the big picture of their treatment
Basic Concepts of Pharmacodynamics
- site of action = location where drug exerts its effect
- mechanism of action = how a drug produces its effects
- receptor site = site on a cell wall where a drug exerts its effects
what is the dose curve and maximal efficacy related to?
pharmacodynamics
response of a drug to a proportional dose
define pharmacodynamics
the relationship between how the body interacts with a drug
Dose
- the exact amount of a drug administered to produce a specific effect
- want doses that fall on a linear curve because they actually bring about a response within the threshold
- doctors normally start with a small dose
threshold dose
lowest dose you see with an actual response
max effect/ceiling effect dose
when you increase the dose to a maximal amount, it plateaus and stops at the max/ceiling effect
Potency
measure of strength, or concentration of a drug required to produce a specific effect
–be able to determine how potent a drug is on a chart
Drug safety is determined by what?
the therapeutic index!! aka median effective and toxic doses
what is the therapeutic index?
- the amount of drug that creates a toxic response (adverse/lethal side effects) for 50% of the people = median toxic dose
- the amount of drug that creates a beneficial dose for 50% of the people = median beneficial dose
- TI = median toxic dose (TD50)/Median beneficial dose (ED50)
- the higher the therapeutic index, the safer the drug typically is
Examples of therapeutic index that is low, but still on the market
- TI is low (~1) in antihistamines because the drowsy-ness side effects are prevalent for more people than the benefits
- TI is reallllly low for chemotherapy, but if this drug isn’t approved, then a lot of people wouldn’t get these benefits
Drug selectivity
- Selective: a 100% selective drug only reacts with a specific receptor in a specific kind of cell in a specific tissue
- Non-selective: a drug that binds with every receptor in the body
give an example of a non-selective drug
aspirin based products, NSAIDS, bind with any receptor that is a cox receptor
New techniques for drug delivery
- controlled release preparations
- implanted drug delivery systems
- targeting drug delivery to specific cells and tissues
Controlled release preparations for drug delivery
coating on drugs so the liver takes care of the coating, but the drug is more slowly dispensed and more bioavailable in the system
Implanted drug delivery systems
patch that continuously releases