Pharmacology 1 Flashcards
What is Pharmacology
Defined as the study of substances that interact with living systems thro chemical processes, especially by binding to regulatory molecules and activating or inhibiting normal body processes
What is a drug
Defined as a natural product, chemical substance, or pharmaceutical preparation intended for administration to a human or animal to diagnose or treat a disease
How does the body handle drugs
ADME
Absorption, distribution, metabolism, elimination
What are pharmacokinetics
how the body handles the drug
Bioavailability
The fraction of the administered drug that reaches the systemic circulation
Onset of Action
Time after administration at which you see the drug effect
duration of action
time during which plasma concentration stays above the MEC for desired effect
half-life
time required for plasma concentration of a dug to decrease by 1/2 after absorption and distribution are complete
Therapeutic Window
Where you want to effects to occur. it above the MEC for desired response and below the MEC for adverse response
Whats the MEC
Min effective concentration
What happens during distribution
After reaching the blood stream, drugs get distributed into various tissues in the body in two phases
Initial phase of distribution
Distribution to interstitial and intracellular space, and to highly perfused organs such as liver, kidney and brain
Second Phase of distribution
Distribution to muscles, most viscera, skin, bone and fat that is slower
What does drug metabolism (biotransformation) do
Enhances elimination of drugs by increasing their excretion, terminate the action of drugs and endogenous substance and activates certain prodrugs to their active form
Where are the sites of metabolsim
Mainly in the liver, kidneys play an important role in the metabolism of some drugs, a few are done in blood and intestinal wall
What are the two forms a drug can be in when excreted
it could be unchanged or it can be converted to metabolites
what kind of compounds do excretory organs expel best (lungs exuded)
Polar compounds are excreted much easier than substances with high lipid solubility
What must happen to lipid soluble drugs to be eliminated
they must be metabolized to more polar compounds before they can be excreted
What kind of drugs are excreted in feces
Unabsorbed oral drugs or drug metabolites excreted either in the bile or into the intestinal tract and are not reabsorbed
Why is excretion of the lungs important
Mainly for the elimination of anesthetic gases and volatile compounds such as ethanol
whats the most important organ for excreting drugs and their metabolites
the kidneys
What is Pharmacodynamics
Study of what drugs do to the body. Drug effects, mec of action, measurement of drug action, modulation of drug action
what are some common drug targets
receptors, enzymes, carrier molecules, voltage-gated ion channels
What are receptors as drug targets
A structure on the surface of a cell (or inside a cell) that selectively received and binds a specific substance causing a change in cell function
what are enzymes as drug tragets
usually macro-molecules proteins that act as a catalyst
Carrier molecules a drug targets
transport a chemical across a membrane with in the body to allow it work
Ion channels as drug targets
allow passage of ions across bio membrane and allow them to open and or close
what is signal transuction
An extracellular signaling molecule (ligand or agonist) activates a receptor on the cell membrane and this receptor in turn activates intracellular ‘second messagers” that cause a response
what is the dose in pharmacodynamics
the amount of drug administered
what is response in pharmacodynamics
the effect
what is the potency of a drug
The amount of drug needed to produce a given effect
the dose causing 50% of the max effect is the EC50
what is efficacy
Efficacy (maximal efficacy) is the greatest effect (Emax) an agonist can produce if the dose is taken to very high levels
What is an agonist
a molecule that binds to a receptor, producing a physiological or pharmacological reponse
What is a partial agonist
A molecule that binds to a receptor, producing a less than full physiological or pharmacological response
what is an antagonist (blocker)
A molecule that binds to a receptor and prevents the binding of an agonist and thus prevents or reduces the effect of agonist. an ideal antagonist does not produce any response by itself
competitive Antagonist effect on DRC
shift the DR to the right, and does not affect the efficacy of the agonist until all receptors are occupied (parallel shift)
Non-competitive antagonist effect on DRC
shifts it to the right, but also reduces the efficacy of the agonist (non-parallel shift)
What are the effects of drugs classified under
Desirable (therapeutic) and undesirable
What are the classifications of undesirable effects
Non-deleterious (side effects)
deleterious (toxic effects)
What is an adverse drug event (ADV)
a reaction to a drug that is harmful or an unintended response (could be an allergy or organ toxicity)
What is an ADR
adverse drug effect
