Lecture 1: intro Flashcards
What is a mechanism of action?
a cell signaling system or process that is changed/impacted by the way a drug interacts with a target molecule
what is a ligand
drug
any substance that brings about a change in biological function through its chemical actions.
what is a receptor
target molecule
a macromolecule (target molecule) in the membrane or inside of the cell that binds with a drug molecule.
what can a drug act as when it binds to a receptor
an agonist (or activator)
or
an antagonist (or inhibitor)
what are the criteria for drug (ligand) attachment to target molecule (receptor)
size, electrical charge, shape, atomic composition
describe the fit and effect of natural chemicals, agonist drug, and antagonist drugs at receptor site
Before Drug (natural chemical)- fits into receptor site and produces normal cellular activity
Agonist Drug- fits into receptor sites BETTER and produces enhanced cellular activity
Antagonist drug- fits into receptor site like a blocker and creates no cellular response, inhibits activity
How do drugs interact with receptors?
By means of chemical forces or bonds
Strong bonds =
covalent
ionic bonds =
electrostatic
weak bonds
hydrophobic
what determines affinity for a ligand to bind
the strength of the bond it holds- the stronger the bond the more attraction it has for the receptor site
What is drug selectivity
degree to which a drug acts on a given site relative to other sites
—how well a drug works at one site compared to another
Relatively nonselective drugs:
affect many different tissues or organs (e.g.,atropine- muscle relaxer- eyes, digestive tract, etc)
Relatively selective drugs:
affect targeted areas (e.g., NSAIDs such as aspirin andibuprofen only targets areas of inflammation)
Highly selective drugsaffect
a single organ or system (e.g.,digoxin- heart, increases pump efficiency for congestive heart failure, sleep aids -brain)
Define poisons
drugs that have almost exclusively harmful effects.
- warfarin- used as a blood thinner but is also in rat poison so they bleed to death
what kind of drugs are synthesized within the body
hormones
Define toxins
poisons of biologic origin, synthesized by plants or animals.
Inorganic poisons
poisons such as lead or arsenic.( consist of metallic and non metallic compounds)
what chemical shape are more than half of all useful drugs
chiral- 4 unique attachment sites
How are drugs normally sold/ what are the common ideas of them
- often sold as racemic mixtures of enantiomers (S and R isomers)
- often one enantiomer is more active than the other
- often one is more susceptible than the other to drug-metabolizing enzymes
- as result, duration of action of one enantiomer may be quite different than the other
-one usually active while the other is inactive
what can’t drugs do
drugs cannot change the basic nature of biologic functions or create new functions
- cant exceed normal biological speed of doing things
what can drugs speed up/slow down
drugs can speed up or slow down biochemical reactions but can only affect at the rate that existing biologic functions proceed
- after the maximum dose of a drug it may not help
how will a drug reach its site of action from administration site
a useful drug must have the necessary properties to be transported from its site of administration to its site of action (whether it is oral, rectal, gel- must have correct chemical properties to make it into blood or path it needs to go to)
what does a practical drug need to reach its target site and be productive
a practical drug should be inactivated or excreted at a reasonable rate so that its action will have enough effect once it is in its target area
( should be inactive until it reaches place you want it to occur)
Pharmacodynamics is
determines the amount and variation of drug responses on the body
- the actions of the drug on the body
(MoA, therapeutic effect, toxic effect).
what does pharmacodynamics involve
receptor binding, post receptor effects, and chemical interactions
how are many drugs classified
based on the basis of their primary receptor affinity
Examples of pharmodynamics
- receptors, effectors
- dose-response curves
- agonists, antagonist
- signaling mechanisms
- receptor regulation
Pharmacokinetics (PK or ADME) describes
the effects of the body on drugs.
- It determines the onset, duration, and intensity of a drug’s effect.
examples of Pharmacokinetics (actions of the body on the drug)
- movement of drug in body
- absorption
- distribution
- metabolism
- elimination
What is biodisposition
a term used to describe the processes of metabolism and excretion.
PK and particular patients
- PK aids in the choice and administration of drugs for particular patients
- Patients PK depends on patient related factors (age, genetics, etc) and chemical properties
-individual physiology can affect PK
what can be used to predict the PK parameters in populations?
patient related factors
PK-PD chart
Black box warnings are
meant to draw attention to a medication’s serious or life-threatening side effects or risks
What are indications
reason to use a specific drug
saying that the use of a drug is for a specific disease
” diabetes is an indication for insulin”
What are contraindictions
condition that serves as a reason NOT to take a certain medication (would cause harm to patient)
cautions
off-label
When the indication, dose, or form of a drug is not FDA approved to treat an illness or symptoms
-might use if all other options exhausted- get consent and document everything !!
Chemical name
name given when drug is first discovered
- describes the atomic or molecular structure of the drug.
-usually too complex for general use
Generic name
(official name)
- is assigned, in the United States, by an official body—the United States Adopted Names (USAN) Council.
-off patent
Brand name
(trademark name)
- company name drug
- gives company proprietary rights to drug ( doesn’t last forever, once expires then can be sold by other companies by different names off the shelf)
-under patent protection
-often related to drugs intended use (lopressor lowers blood pressure)
once a drug is FDA approved what is it given
a generic (official) name and a brand (trademark) name
when a drug is off patent how can it be marketed
by brand or generic name
if a company files for approval to market an off patent drug what are the conditions
the company must use the same generic name but can create their own brand name
- FDA must agree to proposed brand name to eliminate prescription mistakes due to similar/same drug names
What is a prototype drug
a drug(s) that typifies the most important characteristics of the group of drugs.
