Introduction Flashcards
Drug
Substance used in treatment, diagnosis, prevention, or mitigation of disease
- endogenous or xenobiotic
Pharmacology
Science dealing with the properties of drugs and their effects on living systems
- properties and reactions of drugs especially with relation to their therapeutic value
Pharmacy
Separate and complementary health-care profession concerned with collection, preparation, standardization, and dispensing of drugs
- art of preparing, preserving, compounding, and dispensing drugs
Clinical pharmacology
Branch of pharmacology dealing with effectiveness and safety of drugs in the clinical setting
Dose
Amount of drug given at one time
What 4 components are needed to write a dosage?
Amount of drug given (dose), route of administration, interval between doses, and duration of therapy
Potency
Measurement of biological activity
- amount of drug needed to achieve a specified biological effect
- is not medically significant
Efficacy
Ability of a drug to control or cure and illness
- maximal response that can be elicited by a drug
- effectiveness
Vehicle
Carrier or inert medium used as a solvent (or diluent) in which the medicinally active agent is formulated and or administered
Excipients and binders
Inert substances added to a formulation in order to provide suitable consistency to the dosage form
- ex: binder, matrix, base or diluent in pills, tablets, creams, etc
What is the difference between excipients and binders?
- excipient: prevents gumming of machinery that makes the tablet
- binder: helps hold the tablet together
Most of the actual mass of a tablet is _____
Inert
ADME
Disposition of a drug as described by its absorption, distribution, metabolism, and excretion
- qualitative measure
- ex: pharmacokinetics
Pharmacokinetics
Mathematical description of drug disposition in the body
- ex: half life, volume of distribution
- relates drug dose to plasma concentration
Pharmacodynamics
Relates drug concentration to effect
Tolerance
Responsiveness decreases with continued drug administration
- down regulation of receptors
Tachyphylaxis
Rapid development of tolerance
- down regulation of receptors
Trade name
Proper noun identifying a company’s version of that drug
- is always capitalized!
Official name
Nonproprietary, referred to as the generic name
- not capitalized
Type A adverse reaction
Adverse event that can be anticipated based on the known mechanism of the drug
- is usually dose dependent
Type B adverse reaction
Adverse event that is idiosyncratic, unpredictable, and often nondose-dependent
Therapeutic index
Margin of safety, qualitative description
- difference between effective dose and lethal dose
- want a greater difference, or a high therapeutic index
Extra label drug use
Use of a drug in a species, route, dosage, or indication other than indicated on the label
- allowed only by veterinarians and the guidelines of the Animal Medicinal Drug Use Clarification Act
Clinical trial
Study to establish the safety and efficacy of a drug compared to a placebo or an established treatment
Placebo
Substance or treatment with no active therapeutic effect given to deceive the recipient into thinking that it is an active treatment
- accounts for 50% of benefit, so you must have a placebo in a clinical trial as a control
Placebo effect
A beneficial health outcome resulting from a person’s anticipation that an intervention will help them
- commonly seen in owners
Solution
Homogenous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (solvent)
- drug is actually dissolved completely
- can go IV or other routes
Suspension
Colloids with a liquid continuous phase and solid dispersed phase
- water-insoluble drugs may be given as suspensions
- do not need to be mixed prior to use
- NEVER give IV!!
Emulsion
Colloids of 2 immiscible liquids where either phase may be either fatty or aqueous
- lipid-in-water emulsions are usually liquid
- water-in-lipid emulsions are creams
- some can go IV, some can’t
- ex: propofol
- add emulsions to prevent separation of oil and water
Agonist
Substance binding to a receptor that induces a physiologic action
- aka: pressor, mimetic
Antagonist
Substance binding to a receptor that blocks the action of an agonist
- alters tone, does not cause an effect in itself
- aka: blocker, lytic
Are there endogenous antagonists?
No, are always referring to a drug given exogenously
Physiologic antagonist
Occurs when drugs are antagonistic because of opposing effects at different receptors
- both are agonists, but they are opposing in action
- ex: allergic reactions and histamine release
Competitive antagonists
Constant release and reattachment of both agonist and antagonist
- 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
Noncompetitive antagonists
Permanently bind to the receptor
- new receptor must be created
- rare
Dose-response curve
A competitive antagonist can be overcome by adding more agonist
- lower dose: no response
- max dose: all receptors are occupied, so giving more drug will have no effect
Peak concentration
Highest concentration in the drug measured after it is administered before administration of a second dose
Trough concentration
Lowest concentration in the drug measured after it is administered
LD50
Lethal dose at 50% of animals
ED50
Effective dose at 50% of animals
Certain safety factor
Alternative to the therapeutic index as an index of safety
- LD1/ED99
Minimum effective concentration
Lowest concentration that produces a desired effect
- aka: lowest observed (adverse) effect level (LOEL)
Maximum nontoxic dose
MNTD, highest dose that does not produce toxicity
- no observed (adverse) effect level (NOEL)
Maximum nontoxic concentration
Highest concentration that does not produce toxicity
Partial agonist
Pure agonist blocked
- does not stimulate receptor maximally
Trademark symbols
- R: registered trademark, company has exclusive legal right to use trademark
- TM: unregistered trademark, limited legal status but notifies public the company considers this name as their property
What is the purpose of an injectable formulation?
To change the water solubility of a drug and its absorption characteristics
What is the speed of onset for a drug with receptors located in the nucleus?
Slow or delayed onset (hours) due to creation of regulatory proteins
- ex: steroids
The magnitude of the effect of a drug is dependent on what 2 properties?
The amount of the drug present and the affinity constant (rate of binding and release) of that drug for the receptor
- the longer it attaches, the longer the effect
- is true for competitive antagonists
Additive
Summation of effects of 2 drugs
- ex: use one drug to treat gram pos and one to treat gram neg bacteria
Synergistic
2+2=5
- ex: a combo drug used as an antibiotic that is used to treat bacteria sensitive to the combo drug but resistant to each individual drug
Antagonistic combo drug
One drug antagonizes the action of the other
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 - 68.2%
2- 95.4%
3 - 99.7%
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 (usually hormones, heparin, etc)
- most liquids are measured in mg/ml
