Pharmacology Class 2020 Introduction,Pharmacodynamics and Drug Administration Flashcards
Xenobiotics
synthesized outside the body
toxins
poisons that come from biologic orgin
poisons
produce harmful effects on the body.
The dose makes the poison
hormones
synthesized within the body
agonist
activates a process
anatagonist
inhibits effects
receptors
component of a cell or organism that interacts with a drug and initiates the chain of events leading to the drug observed effect
what are required of the drug to be specific?
size
shape
atomic composition
electrical charge
what is the MW of drug in order for it to bind?
100MW
do drugs over 1000MW diffuse readily through compartments of the body?
No, they must be administered directly to the site of their intended effect.
ligand
a molecule that binds to another molecule such as a drug, hormone or neurotransmitter
chirality
enatiomers which are mirror images of eachother.
racemic mixture
a drug that has a mix of both enatiomers or mirror images such as both the S and R enatiomer.
Why would we have only one enatiomer present in a drug?
because it may fit the target receptor better and create a superior effect than the other enatiomer.
Nonselective drugs
affects multiple receptors on different cells and tissues
selective drug
specific binding
What determines the quantitative relations between the dose and concentration of drug and pharmacologic effects?
Receptors
What is responsible for the selectivity of a drug?
Receptor
When a drug binds to a receptor, what is the general effect?
cascade of events
What does the bond between the drug and receptor determine?
The differences in the bind determines how well and how long a drug is going to bind.
what is the strongest bond between a drug and receptor?
Covalent Bond
They are strong and irreversible binding
Results when a pair of electrons is shared between two atoms.
Examples:
Aspirin
Sarin gas ( dangerous)
Penicillin
What is the weaker bond between a drug and receptor?
Electrostatic Bond
What type of bonds do you see in lipid drug receptors?
Hydrophobic
What is the most common use for aspirin today?
prevent platelet aggregation by binding covalently to Platelet COX-1 to prevent platelets from aggregating to other platelets and it takes 2 weeks for new platelets to be made.
How long does it take for aspirin to affect platelets in the body?
15 minutes
Which is more selective, covalent or electrostatic bonds?
Electrostatic
Because it is weaker, it requires the fit between the drug and receptor to be more precise so that it wont fall off unlike covalent which relies on its strength to hold on.
Why do we not want drugs to permanently bind to receptors?
it can produce toxic effects
What is the least common bond interaction?
Hydrophobic Bond
When a drug and receptor bind, what is formed?
D-R Complex
What binds to the same site as the Agonist?
Competitive Inhibitor/ Competitive Antagonist
Allosteric Activator
Binds to a different spot on the receptor to allow the receptor to have a confirmational change that makes it have more affinity for the drug
Agonist
Drugs that have an activating effect on a receptor
Full Agonist
Ligand or drug that bind only to the active form of the receptor to produce a Full Max effect. The plateau is the max on the graph.
Partial Agonist
Ligand binds to both the active and inactive forms of the receptor but with more affinity for the active form of the receptor. It does not reach the max effect
Antagonist
Blocks the agonist from binding to the receptor
How does partial agonist reduce the max effect of the Full Agonist?
Partial Agonist competes with the Full Agonist for the active receptors and prevents the Full Agonist from binding to all the receptor that it needs to in order to get their full effect.
It knocks off the Full Agonist from some of the receptors and you lose full effect of the Full Agonist.
Example:
Methadone drug is a Full Agonist
Inverse Agonist
Drugs that produce the opposite effects of the Agonist.
What is required for a drug to be an Inverse Agonist?
It must have constitutive Activity.
The key thing is that the receptor that it binds to must have constitutive activity which is the activity that occurs in the receptor when there is no ligand bound to it or baseline effect on its own.
What is the difference between an Inverse Agonist or Antagonist?
The antagonist blocks the agonist.
The Inverse Agonist brings down the activity of the receptor by producing the opposite effect.
Antagonist Types
Competitive
NonCompetitive
Allosteric Antagonist
Competitive Antagonist
Antagonist competes for the same binding spot as the ligand/ drug.
It is reversible because as you add more agonist the effects of the competitive antagonist can be overcome.
Spare Receptor
A receptor that does not bind to the drug when the drug concentration is sufficient to reach the max effect.
Example:
90% of receptors are bound produce max effect.
10% are spare receptors. ( Dont need to be bound to produce max effect)
Noncompetitive Antagonist
Bind to the receptor in irreversible manner.
Reduces the maximal response that an agonist can produce.
Cannot overcome effect of the noncompetitive antagonist by increasing concentration of agonist.
Phenochromocytoma
A tumor of the adrenal medulla. It produces excessive amounts of adrenaline and noradrenaline.
Mixed Agonist
Drugs have both agonistic and antagonistic properties.
Chemical Antagonism
A drug may antagonize the actions of a second drug by binding to and inactivating the second drug. It binds to the actual drug.
Physiologic Antagonism
Physiologic functions controlled by opposing regulatory pathways
Regulatory Proteins
Mediate actions of endogenous chemical signals such as neurotransmitter and hormones
Enzymes
Protein receptors that can be activated or inactivated by drugs. Drugs themselves can be enzymes.
Transport Proteins
Receptors that regulate movement of material
Structural Proteins
Structural Elements
Example: Tubulin
Colchicine
A drug that binds to a structural protein. It prevents microtubule assembly and thereby disrupts inflammasome activation.
What type of lipid soluble ligand affect gene expression?
steroids
What is the effect downregulation of receptors?
When ligand binding leads to internalization of the receptor. The synthesis of the receptors is less than the rate of receptor degredation.
Losing total number of cell surface receptors available to bind to the ligand which reduces the responsiveness of the receptor to the ligand.
What type of transmembrane signaling is available?
Enzyme
Nonenzyme
Tachyphylaxis
When responsiveness to a drug diminishes rapidly after administration of a drug which is acute tolerance.