Drug Action Flashcards
Chemical antagonism
An effect where the biological mediator cancels out the effect of the drug
Functional antagonism
An interaction where the effects of both drugs cancel each other out
Competitive antagonism
An effect where an drug binds to a receptor to cause no efficacy, and blocks out all other agonists
Synergism
The effect of the combination of 2 drugs is greater than the sum of its parts
Additive effect
The effect of 2 drugs is equal to the sum of its effects but no greater than its maximum effect
Potentiation
An effect where 1 of the 2 drugs has no effect but the 2nd drug boosts the effect of the first drug
Idiosyncratic effect
A situation where there is no effect or an unusual effect of a drug that is different from the suspected effects
Hypersensitivity
Allergic reaction or an immune response
Tollerance
A decrease in intensity of a drug due to usage over time
Tachyphylaxis
Rapid decrease in responsiveness to a drug
Therapeutic index
A window where drug therapy is effective and not lethal. Within this window, the drug still has an effect on the body but outside the window it can have no effect or is lethal
First pass effect
An effect where the liver metabolizes the drug before sending it into systemic circulation.
Routes of administration
5 types
- enteral
- para enteral
- aerosol
- transdermal
- topical
Types of enteral administration drug dosage forms
5 types
- tablets
- capsules
- solutions
- suspensions
- suppository
Types of para enteral drug dosage forms
3 types
- suspensions
- solutions
- depot
Types of inhalation drug dosage forms
2 types
- aerosol
- gas
Types of transdermal drug dosage forms.
2 types
- patches
- pastes
Types of topical administration
- lotions
- ointments
- powders
- solutions
What are the ways to administer paraenteral drugs
5 types
- intravenous
- intrathecal
- intramuscular
- Intraosseous
- subcutaneous
Transdermal drug application
Applying to skin for prolonged drug administration. Drug defuses into body
What are topical drugs?
Application on to skin for localized treatment
Best drug administration to avoid first pass effect
5 points
- sublingual/buccal
- iv or injection above liver
- rectal
- aerosol
- transdermal
Ways to diffuse through a membrane
- aqueous
- carrier mediated
- lipid diffusion
- pinocytosis
Potency
It’s where the effective concentration or dosage is 50% of the maximum effect
Lung availability / total systemic availability
L/T ratio
During administration of an aerosols drug, a portion of the drug enters the lungs and another hits the mouth and enters the GI tract for first pass effect. Drug that enters lungs over the drug that survives first pass is the LT ratio.
What is an agonist?
Drug or a chemical that binds to receptors and creates an effect on the body
What is an antagonist?
Chemical or drug that binds to receptors but does not create an effect on the body or blocks agonist
What is bioavailability
The amount of drug that reaches systemic circulation
What is enteral drug administration
Drug that is metabolized in the intestines
What is inhalation of the drug
Taking the drug by breathing it in
What is a localized effect
Treating a specific localized area in the body
What is para enteral administration?
Administering a drug that does not go through intestinal metabolization
What is systemic effect?
What can it cause?
-Pertains to the drugs affect on the whole body -potentially causing side effects
What is structured activity relationship?
Relationship between the drugs chemical structure and the outcome has on the body
What is a drug dosage form
The physical state of the drug when giving it to a patient.
What is a route of administration
The portal of entry for a drug to the body
Is the drug the only active ingredient in the medication?
-The drug is the active ingredient in dose formulation
-additives are added to help with metabolization/digestion of the drug in the body.
-for example:
Gelatin(pills) or HFA propellants (mdi)
Ways to administer enteral drugs?
4 types
- oral
- sublingual
- gastric tube
- rectal
What is intrathecal drug administration?
Injection of a drug into spinal cord
What is Intraosseous drug admin?
Injection of drug into marrow bone
What are two benefits of inhalation drug administration?
- Localized effect
- reduced systemic exposure for reduced side effects
What is aqueous diffusion?
2 things
Diffusion through aqueous compartments of the body like interstitial space.
-diffusion through a concentration gradient
What is lipid diffusion
-diffusion across lipid membranes like epithelial cells.
Drugs have to be lipid soluble in order to diffuse across membranes (non-ionized/non-polar)
What is Carrier mediated transport?
Drug resembles substances like sugars and amino acids and passes through membranes through those same channels.
What is pinocytosis
Membrane engulfment and transport into cell interior by bypassing membrane barrier.
What is bioavailability
Proportion of the drug that reaches systemic circulation
What is MIC?
It’s the minimal inhibitory concentration.
-lowest concentration of a drug which microbial population is inhibited
Factors that influence bioavailability
4 factors
- absorption
- inactivation by stomach acids
- metabolic degradation
- blood flow the absorption site
When a drug is given intravenously, where does the drug travel first?
To the organs where there is most blood flow.
Like the brain first
5 layers that the drug must travel before reaching blood stream.
- Airway surface liquid
- epithelial cells
- basement membrane
- interstitium
- capillary vascular network
With regards to metabolism,
What is a phase 1 biochemical reaction.
It converts the drug to a more water soluble form. Which can be excreted by the kidneys
With regards to metabolism,
What is a phase 2 biochemical reaction.
The substance of further transformed by conjugating the substance with a metabolite.
Are all drugs active till they are metabolized?
No,
Some drugs are INACTIVE until they are metabolized
What is the principal organ for drug metabolism?
The liver
What are some potential organs for drug metabolism other than the liver?
- lung
- intestinal wall
- endothelial vascular wall
What is the primary site of drug excretion?
Kidneys
During drug excretion, what does the kidneys remove?
Drug metabolites produced by the liver
What’s is COMT?
Catechol-o-methyltransfertase
-an enzyme that breaks down catecholamine
What are the factors that can increase the L/T ratio.
4 factors
- efficient delivery device
- inhaled drugs with high first pass
- mouth washing w/rinsing and spitting
- use of spacer/reservoir device
What protein does a beta adrenergic drug attach to?
It attaches to a transmembrane receptor of an intracellular enzyme called g-protein
What does the g-protein stimulate?
Adenylyl-Cyclase
What is the body’s response to a drug directly proportional to?
Concentration of the drug
What happens if a drug is administered more frequently then it’s half-life?
Accumulation
