Intro Flashcards
Pharmacokinetics is the study of _ _ which includes
drug motion; absorption, blood levels, distribution, metabolism, and excretion of drugs
Pharmacodynamics involves understanding the interactions between
the chemical components of living systems and the drugs that enter those systems
An IV drug is _% bioavailable
100
A drug must reach the _ _ in sufficient concentration in order to be effective
target tissue
A _ dose may be used to allow for adequate concentration of the drug in the target tissue
loading
Absorption ends in organs of
metabolism and elimination
_ refers to the fraction of a drug dose that reaches the bloodstream
Bioavailability
Absorption is influenced by the ___ of a drug
route of administration
Routes of administration
PO
Parental:
-IV, IM,SQ, IP,IA,IC,Epidural,Etc.
Inhalation
Topical
Speed of absorption in order
IV/IO
Transtracheal (ETT)
Sublingual
Rectal
IM
SQ
Oral
Duration of action
PO>SQ>IM>IV
Drug distribution=
movement of an absorbed drug from the blood to the various tissues of the body
Drug distribution refers to the reversible transfer of a drug between
the blood and the extra vascular fluids and tissues of the body
The most important physical barrier to drug movement is the --_ which limits drugs from entering the central nervous system
blood-brain-barrier (BBB)
An important component of the BBB is the P-glycoprotein pump which is
a protein that protects the brain from exposure to various drugs and substances by actively pumping them out of the cells
Anatomic barriers
BBB, Epidural barrier, Blood-testis barrier
Primary organ of biotransformation is
the liver
Biotransformation aka chemical modification of a drug is the ability of the body
to change a drug from the form in which it was delivered into a form that can be eliminated from the body
Most drugs are metabolized by the _ and eliminated via the _
liver; kidneys (urine)
Drugs may also be secreted via
sweat, bile/feces, lungs, etc
Steady state
amount administered=amount eliminated
Most common diseases that impact drug PK
liver disease, kidney disease, cardiovascular disease
How does cardiovascular disease affect the body
-Alters distribution of blood flow to tissues
-More blood is distributed to the brain and heart
-Alterations in gastrointestinal, hepatic, and renal blood flow impact drug
-P often on multiple drugs
Decreased drug elimination =
increasing plasma drug concentrations
Increased _ _ associated with kidney disease can alter the volume of distribution of drugs
fluid retention
With liver disease, patients may have decreased amounts of
plasma proteins
No drug has a
single effect
Pharmacodynamics is the study of
the mechanisms by which a drug produces a physiologic change within the body
Drug molecules combine w/ _ _ to create a physiologic change in cell function
cellular receptors
Agonist
a drug with a high level of affinity for a receptor
Antagonist
a drug that blocks another drug from binding with a receptor
Therapeutics is the study of
drug use in the tx of disease
Partial agonist
a drug with weak affinity for a receptor
Antagonist are most commonly
reversal drugs
Drugs are used to treat disease based on the following methods:
diagnostic
empirical/ symptomatic
Drug regimen components
route of administration
amount to be given (dosage)
how often to give the drug (frequency)
how long to give the drug (duration)
As an RVT you should be aware of
Indications
Contraindications
Pharmacokinetics
Pharmacodynamics
Side effect is an imprecise term often used to refer to a
drug’s unintended effects that occur within the therapeutic range
Adverse drug reaction is a broad term referring to
unwanted, uncomfortable, or dangerous effects that a drug or the “carriers” in the drug may have
Adverse drug reactions may result from
using the wrong drug, wrong dose, wrong interval, route of administration, wrong patient
Carriers =
inactive ingredients
FDA regulates
drugs, food additives, and medical devices
USDA (US department of agriculture) regulates
biologics (vaccines, serums, antitoxins)
EPA (Environmental protection agency) regulates
pesticides
The FDA requires that each drug be labeled with
-drug name (both generic and trade)
-drug concentration and quantity
-name and address of manufacturer
-controlled substance status
-manufacturers control or lot #
-drugs expiration date
-package insert (list of instructions, warnings)
Effective dose
the amount of the test drug that causes a defined effect in 50% of the animals that receive it (ED50)
Lethal dose
the amount of the test drug that kills 50% of the animals that receive it (LD50)
Thereapeutic index is the
drug dosage or dose that produces the desired effect w/ minimal or no signs of toxicity aka margin of safety
Therapeutic index is determined by
comparing lethal dose and effective dose of the drug (LD50 divided by ED50)
In the US, new veterinary drugs must go through a series of tests mandated by the _
FDA
The larger the number that is produced by dividing LD50 and ED50 the greater the level of _
safety
A wide therapeutic index means that the drug can produce its desired effect without
approaching toxicity
What are residues
quantities of drug that remain in animal products when they are consumed
What is a withdrawal period
the minimum period of time from administering the last dose of medication and the use of meat or other animal-derived products for food
Prescription drugs are regulated by the FDA and are limited to use under the supervision of a veterinarian or physician because of their
potential danger, toxicity concerns, administration difficulty, or other considerations
Prescription drugs are prescribed to animals once a ____ has been established
veterinarian/ client/ patient relationship
Extra label drugs are drugs used in a manner that is
not specifically described on the FDA approved label
Extra label drug use is allowed under what act
Animal Medicinal Drug Use Clarification Act (AMDUCA)
Why are controlled substances considered dangerous
because of their potential for human abuse or misuse
Controlled substances are regulated by the
DEA (Drug enforcement agency)
Schedule levels for controlled drugs
Schedule I
Schedule II/IIN (2/2N)
Schedule III/IIIN (3/3N)
Schedule IV
Schedule V
Controlled substances must be stored in
a locked cabinet or safe
How long should controlled substance records should be kept for
2 years
Dietary supplements fall between category of _ and category of _
food; drugs
What a nutraceutical
a non drug substance that is produced in a purified or extracted form and administered orally to provide agents required for normal body structure and function w/ the intent of improving the health and well-being of animals
What is compounding
manipulation of a drug other than provided for on approved drug label (diluting, mixing with another drug in the same syringe)
Disposal of unwanted drugs
1.Incinerate
2.If cannot incinerate, drugs sent to landfill
3.Never flush
4.Maintain inventory control
5.Always follow federal and state guidelines
