THE SCIENCE OF DRUG ACTION
the molecular changes that happen when a drug binds to a particular site or receptor
what is drug action?
movement of the drug from the site of administration to the blood circulation. nonspecific factors can have a great effect on this
what is absorption?
this alters the magnitude and duration of drug action. if it binds to an area that has no effect. this can be used to prolong the effect of the drug on the body. it could cause competition in drugs which could contribute to an overdose
what is depot binding? also known as silent receptors
what is the goal of therapeutic drug monitoring?
there is a level where half of the population will experience a toxic effect.
by comparing the TD50 and ED50 we can see which dose is appropriate to prevent toxic effects
the wider your therapeutic index is, then the least likely it is to have an overdose or toxic effects
what is therapeutic index?
the physiological or psychological effects that happen when a drug binds
what are drug effects?
drugs that go through the liver goes through this and the metabolic enzymes can break down up to 90% of its bioavailability. oral and rectal administration are more likely.
what is first pass metabolism?
the metabolism and excretion to eliminate the drugs from the body. it goes through two methods one of which: is relational to half-life in that with an amount of time 50% of the drug will be released. and the other which is when there is too much of the drug is there so it is released at a constant rate where the first method will then intervene
what is biotransformation; what is first order kinetics; what is zero order kinetics?
the study of the interaction of drug molecules with specific receptors.
the receptors are the proteins on the cell surfaces or within the cells.
the ligand is the molecule that binds to a receptor with some selectivity.
identifies drugs that act as NT receptors to enhance or reduce the normal functioning of the cell
what is pharmacodynamics?
what are receptors and ligands?
what is neuropharmacology?
in this scenario, the agonist is tussling with the antagonist to bind to the site and the antagonist WINS. This means that the effect of the agonist (which we want) is going to decrease. this is reversible
in this scenario, the agonist is still tussling with the antagonist but the antagonist is "stronger" because it binds to a different site therefore reducing the effect of the binding site so even if the receptor binds to it, the effect will never be as high without the antagonist. the slope is very different than the OG.
when two drugs interact it can have a reduced effect (the end product is less), an additive effect (drug a+b mix making it a greater sum), or potentiation effect (drug a+b increase dramatically when together exceeding their individual effects)
what is a competitive antagonist?
what is a noncompetitive antagonist?
what are the three physiological antagonism?
based on the physical and biochemical interactions of a target site in living tissue
what are specific drug effects?
the most important factor in determining plasma drug levels is the ionization of the drug and if it easily passes the cell membrane
what is ionization?
the nonsynthetic modification of a drug through oxidation. it is the most common method and its end goal is to produce a more water-soluble and less active form for excretion. on the other hand, the synthetic reaction requires the conjugation of the drug with another molecule such as glucuronide (inactivating psychoactive drugs)
what is type I biotransformation?; what is type II biotransformation ? *varied effects
have a high attraction for a receptor and they will bind to the receptor which will initiate a response
will bind to a receptor but they will produce no effects thus having low efficacy. since they do not produce an effect it prohibits the agonist from binding.
intermediate efficacy
does the opposite of what an agonist is supposed to do.
what are receptor agonists?
what are receptor antagonists?
what are partial agonists?
what are inverse agonists?
the repeated use of a drug makes it so that the person has a diminished response to it, so they want more to get that first-time effect
sometimes one drug can diminish the effectiveness of another drug
you are COOKED if this happens to you. the effects of the drug are enhanced after administration. the effects can last a long time and this causes long term physiological changes in the brain.
what is tolerance?
what is cross-tolerance
what is sensitization?
negative expectations may increase levels of anxiety, stress, and pain experience. a warning about a potential side effect lead to greater side effect
what is a nocebo effect?
the most effective route of administration but also the most deadly; the least effective route and safest; a rapid onset but irritates the nasal passages; a very rapid and bypasses blood brain barrier; has a lower side that does pass FPM and a deeper side that does not
what is IV, oral, intranasal, inhalation, and rectal routes of adminstration
*most microsomal enzymes in the liver metabolize drugs.
repeated use of the drug (too much drug) increases the number of enzymes so it gets rid of it faster. also acts on similar drugs. drug tolerance since the drug loses its effectiveness
a drug may cause the enzymes to be blocked so it can not break it down which is deadly and can lead to toxicity since the effects are prolonged. grapefruit juice inhibits psychoactive drugs
what are enzyme inducers?; what are enzyme inhibitors?
with chronic use of a drug, there will be more receptors. this usually happens with chronic receptor antagonist. the "system" is trying to make an effect
the number of receptors is reduced since there is binding occurring. this usually happens with agonists. cause why would the "system"need to overcompensate if there binding occurring.
* different parts of the body will have different characteristics in response to a drug. a goal is to have one receptor have a higher affinity to a specific drug to have a therapeutic effect
what is upregulation?
what is down regulation?
when drugs increase the amount of microsomal enzyme livers so the breakdown is much faster
upregulation and downregulation
occurs in the same environment when drug was given
ur in love after one single administration
what are the metabolic, pharmacodynamic, behavioral, and acute tolerance causes?
a nonspecific effect that is an example of mind-body interaction. involves classical conditioning, social learning, conscious expectations and genetic variants
what is the placebo effect?
what is the blood-brain barrier?
genetics can play a big role in drug-metabolizing enzymes. example: African Americans are much more likely to be underprescribed or overprescribed a drug that either has no effect or too much of an effect. asian groups also have a reduced capacity to reduce capacity to metabolize acetaldehyde which causes them to have a flushed face
what are genetic polymorphisms?
- the amount of drug that produces any effect
- by comparing the different half effective dose then we see how drugs have different potencies but same efficacy
what is dose response curve?
what is ED50?
what is threshold?
- classical conditioning: conditioned response
- operant conditioning: you learn to do something. a reinforcement
- state dependant learning: you learn something drugged and can do it only under drug state
what does behavioral tolerance learning involve?