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Define "Legal" drug?
any substance other than food or device intended for use in the diagnosis, cure, relief, treatment, or prevention of disease, or intended to affect the structure or function of the body
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Define "general" drug?
Any substance that brings about a change in biologic function through its chemical actions
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Define pharmacology?
study of substances that interact with living systems through chemical processes, expecially by binding to a cell component (receptor)and activating or inhibiting normal body processes.
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Define drug therapy?
the treatment of a disease or pathological condition through the sensible use of drugs, the aim of which is to prevent, cure, or control the disease
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List the sources of drugs
Plants, animals, microbial sources, poisons, our own internal hormones, synthetics(biotechnology)
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List the physical properties of drugs
- Solids (Pills)
- Liquids
- gaseous
- proteins, carbohydrates, lipids
- weal acids or weak bases
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Why is drug size important?
Drug has to be able to permeate through walls (3 places are intestinal walls, capillary walls, & blood brain barrier)
Drugs that are too large(high molecular weight) will not move between compartments of the body
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What is the molecular weight of a typical drug?
MW is between 100-1000
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How do drugs interact with receptors?
bonds aka chemical sources
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Name 3 types of bonds and describe each?
covalent-strong, typically not reversible
electrostatic- vary from strong to weak and are most common
hydrophobic bonds-very weak lipid to lipid bonds
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Define affinity
mutual attraction or bond strength between drug and receptor
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Define intrinsic activity
Drug/receptors capability to produce a response
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Why is drug shape important
Fits into receptor like a hand into a glove
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What is pharmokinetics
what the body does to the drugs
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what is pharmodynamics
what the drug does to the body
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What are the four fundamental patways of drug movement?
- absorption=input
- distribution=at liver
- metabolism=drugs in tissues
- elimination=usually in kidneys
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what is site of action
the location where a drug is intended to work
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List the enteral routes of administration
- oral
- sublingual
- nasogastric
- rectal
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List parenteral routes of administration
- intravascular
- intramuscular
- subcutaneous
- intraosseous
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List "other" routes of administration
- inhalation
- intranasal
- intrathecal(CSF)/intraventricular
- topical (skin)
- transdermal
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define passive diffusion
where drug permeates by going down a centration gradient
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lipophilic is,,
lipid soluble
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lipophobic
is water soluble
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hydrophilic is
water soluble
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hydrophobic is..
lipid soluble
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define absorption
transfer of a drug from its site of administration to the bloodstream
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what is bioavailability
the fraction of administered dose that reaches the systemic circulation
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What 3 factors influence absorption?
Surface area
blood flow to absorption site
contact time
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what is factors influence bioavailability
- (1) First-pass hepatic metabolism. (how the liver handles the drug)
- (2) Solubility of drug- eg. in the gi tract, the drug must be mostly lipophilic but have some hydrophilic qualities.
- (3) chemical instability-the fragility to stomach acids
- (4) drug contruction- misconstructed issues
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Explain Distribution
the passage of drug molecules from the bloodstream into tissues and organs
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Factors that influence distribution
- 1. blood flow
- 2. Binding of drugs"trapped" to plasma proteins
- 3. Capillary permeability-determined by natures of drug and capillary
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What is the major site for drug metabolism?
Liver
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Explain the 2 phases of metabolism
- Phase 1-many families of enzymes modify drug molecules so that they can become more polar
- Phase 2 conjugation with glucuronic acid which gives a more polar, water soluble, metabolite
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Elaborate on excretion of a drug?
The irreversible removal of a drug from the body mostly done in the kidney
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define half-life
the time required for serum concentrations to decrease by half after absorption and distributions phasesare complete
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Where do hydrophibic molecules tend to go
to cell membranes
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where do hydrophilic molecules tend to go
kidneys
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Define agonist
drug that binds directly to a receptor and achieves desired response
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define indirect agonist
a drug that helps other hormone or neurotransmitter hit the target cell and achieve a response. Also some indirect agonists that inhibit some enzymes to achieve a desired effect
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what are mixed agonists
drugs that acheive both direct and indirect agonistic actions
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what are antagonists
drugs that bind to a receptor in order to block other molecules from binding. end result is no response by cell.
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What is the difference between reversible and irreversible antagonists?
reversible binds to site or fights to bind with other molecules for spots but binding is not permanent. irreversible binding is permanent in its connection
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define minimum dose
smallest effective dose
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maximum dose
largest safe dose
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effective dose
dose between min and max without causing signs and symptoms of drug toxicity
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loading dose
higher initial dose to be followed by lower doses. usually iv
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maintenance dose
steady therapeutic dose
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What are some factors affecting response to drugs
Size, age, genetics, time taken receptors
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Explain side affects
when drug affects us in an unwanted but not fatal way. It can be caused by having the same receptors in other areas of the body that are not the target cells
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Define toxicology
branch of pharmocology which deas with the severely undesirable effects of chemicals on living systems
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