Flashcards in Lecture 1 Deck (48):
1
Drug
a substance used in the treatment, diagnosis, prevention, or mitigation of disease (Endogenous or xenobioitc)
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Pharmacology
A science of dealing with the properties of drugs and their effects on living systems. The properties and reactions of drugs especially with relation to their therapeutic value.
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Pharmacy
A separate and complementary health-care profession concerned with collection, preparation, standardization, and dispensing of drugs. The art or practice of preparing, preserving, compounding, and dispensing drugs. (Pharmacy ≠ pharmacology).
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Clinical Pharmacology
The branch of pharmacology that deals directly with the effectiveness and safety of the drugs in the clinical setting (patients)
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Dosage
The amount of drug given (dose), the route of administration, the interval between doses, and the duration of therapy (ex: 5 mg/kg orally every 12 hrs for 5 days)
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Potency
A relative measurement of biological activity. The amount of drug needed to achieve a specific biological effect. Potency is seldom of medical significance, and it is often confused with efficacy. (example given in class: one of the few times that potency matters would be with tranquilizers and large animals… you want the dose to be more potent so it can fit in a dart and not have to be infused gradually)
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Efficacy
effectiveness. The ability of a drug to control or cure an illness
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Excipients and binders
Used to bulk up solid formulations and help the active ingredient stick together.
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Vehicle
An inert medium or solvent/diluent in which the medically active substance is administered.
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ADME
The disposition of a drug as described by its absorption, distribution, metabolism, and excretion. i.e. pharmacokinetics
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Pharmacokinetics
A mathematical description of drug disposition in the body (e.g., half-life, volume of distribution, etc). Relates drug dose to plasma concentration.
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Pharmacodynamics
Relates the drug concentration to effect. It is what the drug produces physiologically.
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Tolerance
Responsiveness to drug decreases with continued administration
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Tachyphylaxis
Rapid development of tolerance
Example: vasodilation from nitroglycerin. 12 hour dose with the drug and then 12 hours without because the body becomes tolerant after 12 hours.
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Trade name of drug versus official name of a drug
Official name: (nonproprietary; often referred to as the “generic” name; NOT capitalized)
Langston will always give the official name (may give the trade name)
Trade name: (proprietary; proper noun, it is capitalized)
This is the company’s version of that drug -- will include a registered or unregistered trademark
EX// o-p-dd; mitotane; Lysodren
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Adverse reaction: type A versus type B
Type A: an adverse event that can be anticipated based on the known mechanism of the drug. Usually dose-dependent.
Type B: an adverse event that is idiosyncratic (specific to the individual), unpredictable, and often nondose-dependent
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Therapeutic Index
lethal dose (toxic dose) of 50% of animals divided by the effective dose in 50% of animals (LD50/ED50). This is an index of safety and we use it as a qualitative term. It is more about a margin of safety rather than an absolute number. We want a drug with a high therapeutic index or high margin of safety.
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Extra‐label drug use
the use of a drug in species, route, dosage, or indication other than indicated on the label. Such use is allowed only by veterinarians and only according to the guidelines of the Animal Medicinal Drug Use Clarification Act (AMDUCA).
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Clinical Trial
a study to establish the safety and efficacy of a drug compared to a placebo or an established treatment.
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Placebo and Placebo Effect
Placebo: a substance or treatment with no active therapeutic effect given deceive the recipient into thinking that it is an active treatment
Placebo effect: a beneficial health outcome resulting from a person’s anticipation that an intervention will help them
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Suspension
colloids with a liquid continuous phase and solid dispersed phase. Water insoluble drugs may be given as a suspension
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Solution
The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent)
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Agonist
a substance binding to a receptor that induces a physiologic action
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Antagonist
a substance binding to a receptor that blocks the action of an agonist
A physiologic antagonist has an opposing effect at a different receptor. For example histamine (decreases blood pressure) and epinephrine (increases blood pressure)
A pharmacologic antagonist blocks the effect on the same receptor, these are drugs.
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Competitive antagonists
agonists and antagonists don’t permanently bind to a receptor so they are constantly binding and releasing. This means they must constantly compete with the other for the receptor. The magnitude of the effect of the agonist/antagonist is due to the amount of drug present and the drug’s affinity for the receptor.
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Noncompetitive antagonists
permanently bind to the receptor (new receptor must be created; rare)
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Dose-Response Curve
a curve that determines how much drug (x-axis) causes a particular effect or side effect in the body (y-axis). It also allows you to compare agonists and antagonists to the original drugs.
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peak concentration
The highest concentration of a drug in a patient’s bloodstream, usually right after
a dose is administered
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LD50, ED50, LD1, Certain Safety Factor
LD50- dose that kills 50% of subjects
ED50- dose that is effective in 50% of subjects
LD1- dose that kills 1% of subjects
Certain Safety Factor- (LD1/ED99) alternative to the therapeutic index as an index of safety -LD1/ED99 is now more commonly used than LD50/ED50
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Minimum Effective Concentration (MEC)
Lowest concentration that produces a desired effect
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trough concentration
The lowest drug concentration in a dosing interval. Always occurs immediately before the next dose.
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LD50, ED50, LD1, Certain Safety Factor
LD50- dose that kills 50% of subjects
ED50- dose that is effective in 50% of subjects
LD1- dose that kills 1% of subjects
Certain Safety Factor- (LD1/ED99) alternative to the therapeutic index as an index of safety -LD1/ED99 is now more commonly used than LD50/ED50
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No Observed (Adverse) Effect Level (NOEL/NOAEL)
The maximum dose that does not produce toxicity. Same as maximum nontoxic dose.
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physiologic antagonist
occurs when drugs are antagonistic because of opposing effects at different receptors
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Partial agonists
Drugs that bind to and activate a given receptor, but have only partial efficacy at the receptor relative to a full agonist.
36
agonist/antagonist
Agonist- A substance binding to a receptor that induces a physiologic action
Antagonist- a substance binding to a receptor that blocks the action of an agonist
37
Know the proper grammatical use of drug trade names versus the official name of the drug; including capitalization rules and the use of trademark symbols.
Official Name/Generic Name- Not capitalized
Trade Name- Capitalized
A trade name is a proper noun identifying a company’s version of that drug. Typically the trade name of a drug is also a registered or unregistered trademark. The registered trademark symbol gives the company exclusive legal right to use that trademark. An unregistered trademark provides limited legal status but notifies public that the company considers the name as their property.
38
Contrast potency versus efficacy in terms of the therapeutic utility of a drug.
Potency → the amount of the drug required to produce a certain response
Efficacy→ maximal response that can be elicited by a drug
Most potent does not always mean it is the most efficient, we want efficacy in a drug and not potency.
39
Why might different injectable formulations exist for the same drug? Likewise for different oral formulations.
There are different formulas for different injectable and oral drugs because the same medicine can treat different diseases with different formulations
EX: Ivermectin Dose is different for heartworm prevention vs sarcoptic mange
There are also different formulations between each animal
EX. Dogs and cats will not have the same formula
Also, different formulation will last longer in the body
-i.e. Penicillin with different ingredients make it lass water soluble thus making it "long lasting"
40
Contrast the relative speed of onset for a drug with receptors located within the nucleus of a cell versus the cell membrane/enzyme/2ndmessenger.
Receptors in nucleus of a cell: e.g. steroids, receptor-agonist complex is internalized and translocated to the nucleus where it alters protein synthesis, slower acting
Receptors in the cell membrane/enzyme/2nd messenger: e.g. insulin, activating ion channels, acts fast
41
) Explain how the concentration of a drug at the receptor site and the affinity of the drug for that receptor affects the magnitude of the effect of a competitive agonist or a competitive antagonist.
A competitive antagonist binds to the same site as the agonist but does not activate it but instead blocks the agonist’s action. The magnitude of the effect is dependent on the amount of drug present and the affinity constant (rate of binding and release) of that drug for the receptor. A competitive antagonist binds the receptor in a reversible way without activating the effector system for that receptor. In the presence of a competitive antagonist, the log dose response curve is shifted to higher doses (to the right) but the same maximal effect is reached. A competitive antagonist can be overcome by adding more agonist. If you give more agonist than antagonist you can have the same effect but you just have to give a larger dose to have the same effect.
42
Explain what a noncompetitive antagonist is and how it differs from a competitive antagonist in its ability to override an agonist of the same receptor.
block agonists by permanently binding to the receptor. New receptor must be created. Rare.
A noncompetitive antagonist shifts the agonist curve downward, instead of to the right like a competitive does.
43
Regarding drug interactions, what do the following terms imply: synergy, antagonism, and additive effects?
Synergistic: drugs work together to produce a stronger effect rather than one drug on its own.
2+2=5
Antagonist: drugs work against each other and have decreased efficacy.
2+2=1
Additive: drugs work as if they were being given on their own.
2+2=4
44
Assuming a “normal distribution”, state the percentage of that population that would be expected to be encompassed by 1, 2, and 3 standard deviations from the mean response.
1 standard deviation away: 68.2%
2 SDs away: 95.4%
3 SDs away: 99.7%
45
Be able to make necessary conversions in units of measurement.
Calculations
46
Explain why the concentration of a drug might be stated in “units per ml” rather than “mg per ml”.
A unit is a measurement of biological activity. Units are used when there is difficulty creating the same potency (per weight of drug) in every batch of drug produced.
47
Be able to make necessary conversions in units of measurement.
Calculations Lecture
48