Chapter One - Basic Pharmacology Flashcards
Define:
Psychopharamacology
The study of how drugs affect mood, perception, thinking, or behaviour.
Define:
Psychoactive Drugs
These are drugs that affect mood, perception, thinking, or behaviour by acting on the nervous system.
ie. Cocaine, caffeine, alcohol.
Define:
Instrumental Drug Use
Use of a drug to address a specific purpose [medical].
Define:
Recreational Drug Use
Using a drug entirely to experience the effects [partying].
Define:
Behavioral Pharmacology
The study of how drugs affect behavior.
Sometimes behavioral pharmacologists emphasize principles used in the field of behavior analysis.
Define:
Neuropsychopharmacology
The study of how drugs affect the nervous system and how these nervous sytem changes alter behaviour.
What is a drug?
Traditional Defintion:
- any substance that alters the physiology of the body.
Contemporary Defintion:
- any substance that alters the physiology of the body but is NOT food.
Different Drug Names?
- Generic Name: A non-proprietary name is a simple name for a drug that shows its classification and sets it apart from others in the same group.
- Trade Name: a trademarked name a company provides for a drug.
- Chemical Name: details a drug’s chemical structure.
- Street Name: given by those who use, sell, or illegally make recreational drugs
How are drug doses reported?
Drugs tend to be reported in ml per kg.
A standardized reporting enables comparisons across species.
What is a dose response curve [DRC] used to establish?
Used to establish a picture of the physiological and behavioral effects of a drug.
What are 2 important landmarks for dosing?
- ED50, median effective dose.
- LD50, median lethal dose.
Define:
Potency
The amount of a drug used to produce a certain magnitude of effect.
Can be seen through the differences in ED50, the lower this is the higher the potency level.
When examining graphs, the farther the curve is to the left = more potent.
Define:
Effectiveness
Refers to a drugs ability to elicit a response, regardless of the dosage.
Two types of psychoactive drug effects?
- Objective.
- Subjective.
Objective Effects?
Pharmacological effects that can be directly observed by other people.
Subjective Effects?
Pharmacological effects that cannot be directly observed by other people.
Define:
Therapeutic Index
This conveys the distance between therapeutic versus toxic dosages of drugs.
It is the lethal dose divided by therapeutic dose.
Higher on the therapeutic side = the safer the drug is.
Define:
Pharmacodynamics
The psychological actions of drugs.
Define:
Pharmacokinetics
How drugs move and pass through the body.
Four steps [fifth is debated but not included].
- Absorption.
- Distribution.
- Biotransformation.
- Elimination.
Ingestion/administration is debated as the first step, but not added.
Define:
Pharmacogenetics
This is how genetic differences influence a drugs pharmacokinetic and pharmacodynamic effects/properties.
Pharmacokinetics:
Absorption
Refers to the passage of the drug from the site of administration to the bloodstream.
Absorption:
Intravenous
Administered into a vein.
Fastest route, as it goes directly into the bloodstream [no membranes/barriers to pass through].
Absorption:
Intramuscular
Injected into a muscle.
Define:
Subcutaneous
Administered under the skin.
What is the pKa?
[absorption]
This is the negative base -10 logarithm of the acid dissociation constant [Ka] of a solution.
The closer the pKa value is to the local pH level the easier the drug will be absorbed
Define:
Distribution
- The passage of drugs from the bloodstream into organs.
- Must penetrate membranes.
Define:
Biotransformation
- Drug broken down into metabolites by enzymes.
- Five different phases.
Biotransformation:
Phase 1
Normally invovles P450 enzymes and produces a water-soluble metabolite.
Biotransformation:
Phase 2
Occurs through conjugation of a drug’s metabolites, making them resistant to passive diffusion.
Biotransformation:
First Pass Metabolism
Idea that drugs absorbed through the digestive track reach the liver before they reach the heart, meaning these drugs are broken down to an extent before they go anywhere else in the body.
Biotransformation:
Active Metabolites
- Some metabolites of drugs offer physiological effects of their own.
- Not all drugs have metabolites and are the active component themselves.
Biotransformation:
Prodrugs
These are compounds that are transformed in the body to produce the active drug.
Define:
Elimination
- Drugs, metabolites or both are eliminated from body.
- Basic functionality is that it pulls out all of the toxins in the bloodstream and allows for excretion [pee] through the kidney filteration.
Elimination:
Half Life
- The time is takes for the body to eliminate half of a given blood level of a drug.
- Half life curve is a degradation of when 100% of the drug was in the blood all the way to 0%, overtime allowing for the visual of how the drug was excreted.
Elimination:
Rate of Elimination
- This is modeled using rate-order kinetics.
- Zero order kinetics: proceeds at a constant rate.
- First order kinetics: the rate of elimintation is dependant on the concetration of the drug.
Define:
Ingestion/Administration
- How the drug enters the body.
- Is highly debated as the first step of pharmacokinetics or if it is a stand alone.
Define:
Blood Brain Barrier
Barrier of tight junctions that prevent pathogens, hormones, and other substances from entering the brain.
Define:
Passive Diffusion
Drug should be:
- lipid soluble.
- uncharged.
- relatively small.
Define:
Active transport
- Larger and/or polar [charged] molecules.
Define:
Effective Dose
More potent, less drug needed for the same amount of effect.
Define:
Therapeutic Window
- When drugs are administered for therapeutic purposes, there is a range where you get wanted effects.
- Too high can cause unwanted side effects.
- Too low may show no desired effects.
Pharamacodynamics:
MoA
- Mechanism of Action.
- Different drugs may alter different neurotransmitters or neurotransmitter systems.
Define:
Preclinical Testing
When a new chemical is discovered or synthesized by researchers, it must be tested extensively before it can be developed into a useful drug.
Clincal Testing:
Phase I
Pharmacokinetic and Safety Testing:
- between 20 and 100 healthy volunteers are paid to participate in determining the investgational pharmacokinetics, as well as safety.
Clincal Testing:
Phase II
Small-Scale Effectiveness Testing:
- between 100-300 patient volunteers participate in a closely supervisers examination of the investigational drug’s effectiveness and possible adverse effects.
Clincal Testing:
Phase III
Large-Scale Effectiveness Testing:
- Clinical trials are expanded to include 1000-3000 patients volunteers who help to determine drug efficacy, safety, and other outcome resulting from longer-term drug use.
Clincal Testing:
Phase IV
Postmarketing Studies:
- The new drug is available for prescription to any individual who might benefit from it.
Define:
Off-Label Use
- Physicians determine if the drug has other potential benefits and prescribe it to treat other disorders.
Define:
Drug Safety
It is common to establish the LD50 & ED50 to provide an idea of safety.
Define:
Drug Antagonism
When one drug diminished the effect of another.
Define:
Primary Effect
The effect for which a drug is taken.
Define:
Bioavailability
- Whether it gets to its site of action and how fast and how much of it gets there.
- Can be determined by its route of administration.
Define:
Side Effect
Any other effect, harmful or not.
Define:
Parental Administration
- Involve injection through the skin into various parts of the body.
- Further subdivided, depending on where in the body the drug is injected.
Define:
Vehicle
Before a drug can be injected, it must be in a form that can pass through syringe and needle, a liquid, which is called the vehicle.
Define:
Intreperitoneal
- Needle is injected directly into the peritoneal cavity.
Define:
Depot Injections
- Some drugs need to be taken chronically to prevent the symptoms of a disease or disorder from reappearing.
- ie. antipsychotics.
- Depot injection entail the drug being dissolved in a high concentration in a viscous oil which is then injected into a muscle, usually the buttock.
Define:
Transdermal Administration
Absorbed through the skin.
Ion Trapping
- drugs can get trapped on one side of the membrane.
- has to do with acids and bases.
Protein Binding
- Blood contains a large numer of large protein molecules that, owing to their size, cannot diffuse out of the pores of the capillaries. Some drugs molecules become bound to protein molecules so strongly that they remain attached and never reach their site of action.
Define:
Placental Barrier
The blood of the fetus and the blood of the mother are not continuous. Nutrients are transferred to the blood of the fetus through a membrane in the placenta.
Define:
Depression of Enzyme Systems
- When 2 drugs that use the same enzyme are introduced into the body at the same time, ,the metabolism of each will be depressed because both will be competing for the enzyme.
