Intro Flashcards
What is a drug?
Substance recognized in an official pharmacopoeia
Substance used for diagnosis, treatment, or prevention of a disease
Substance other than food intended to affect structure/function of the body
What is pharmacology
Study of interactions of drugs with living systems
What is the science of drug preparation
Pharmacy
Study of poisons and their treatments
Toxicology
What is the difference between pharmokinestics and pharmodynamics?
Pharmokinetics = absorption, distribution, metabolism, and excretion (deposition an movement of drug in the body)
Pharmodynamics = mechanism of action of the drug
What database is used to determine food residues and withdraw times of food animals?
FARAD
Food animal residue avoidance databank
What are the 4 catagories of drugs
OTC
Prescription
Biologics
Controlled
How are controlled drugs regulated and how are they rated?
Regulated by DEA
5 classes based on potential for abuse - class 1 has highest abuse potential
What are the factors that modify drug dose and response
Animal related
Drug related
Environment
How must you consider species differences when modifying drug dose and response?
Anatomical/physiological/biochemical differences
Vomiting animals
Urine pH
Drug metabolizing enzymes
Plasma binding proteins
What breed is sensitive to ivermectin
Collies
What species are sensitive to phenothiazanes??
Boxers
What species are tolerant to droperidotfentanyl
Australian terriers
On the individual level, how can drug response differ?
Genetic differences can lead to tolerance, sensitivities to certain drugs
Idiosyncratic reactions
What differences are seen in the newborn that alter drug response
Decreased metabolism, excretion
Decreased blood brain barrier
Increased total body water
Decreased plasma protein binding
Young animals are susceptible to what adverse side effect by tetracycline ?
Yellow discoloration of teeth (animals with dental development)
Young animals are susceptible to what adverse side effect by fluoroquniolones
Cartilage damage
Young animals are susceptible to what adverse side effect by glucocorticoids?
Growth inhibition
In geriatric patients, what changes will modify drug response
Decreased metabolism, cardiac output, renal function, hepatic blood flow
Other chronic disease
What differences are seen between males and females that can affect drug response?
Females generally have more fat than males
Reproductive cycle in females (pregnancy and lactation)
Differences in drug biotransformation
Calm animals may need lower doses of _____________ than aggressive animals
CNS depressants
What is an idiosyncratic reaction
Genetically determined unpredictable abnormal reactions
Not dose dependent and require drug withdrawal
Most idiosyncratic reactions are caused by the formation of ______________________ which can bind to cellular macromolecules and result in cell damage
Reactive drug metabolites
What idiosyncratic reaction can enrofloxacin cause in cats?
Retinal damage
What idiosyncratic reaction can griseofulvin cause in cats?
Liver damage
What idiosyncratic reaction can occur with captopril in dogs
Renal disease
When drug acts as an antigen and antigen-antibody reactions cause and immune response
Hypersensitivity
Some drugs act as hapten
How can disease affect drug response?
Liver disease decrease drug metabolism
Kidney disease decrease renal excretion
Heart failure decreased organ blood flow and renal excretion
___________ is unusual resistance to the ordinary dose of the drug
Tolerance
What are the four types of tolerance
Natural
Acquired- enzyme induction/increase excretion
Cross tolerance
Tachyphylaxis - acute acquired tolerance
Will absorption be faster before or after meals?
Before
CNS stimulants are more effective during the _______ and CNS depressants are more effective at ________
Day; night
When the rate of elimination is slower than the rate of absorption
Cumulation
What is a drug-drug interaction
Administration of drugs concurrently or sequentially
What is an example of combined antihypertensive therapy, beneficial drug interactions
ACE inhibitor- thiazide diuretic
ACE inhibitors elevate potassium levels
Thiazide decreased postassium levels
Trimethoprim-sulfonamide or PenicillinG- streptomycin are examples of what beneficial drug drug interaction
Combined antimicrobial therapy
Why do two aminoglycoside antibiotics concurrently produce an undesirable drug interactions
Both are nephrotoxic - kidney damage
What are the four types of drug-drug interactions?
Summation
Potentiation
Synergism
Antagonism
What is summation of a drug?
The sum of the effects of drugs (1+1=2)
What is potentiation of a drug?
Combined effect of two drugs is greater than the sum of the two drugs acting independently (have different actions/affects)
What is synergism
Exaggeration of the effect of a drug by giving another drug that has the same action
What is an example two drugs that have summation
Two anticholinergics
Examples of drugs with potentiation effect?
Probenecid-penicillin G
Epinephrine-procaine
What are examples of drugs with a synergistic effect?
Neuroleptic-inhalation anesthetic
Trimethoprim-sulfonamide
What is drug antagonism
Administration of a drug results in the decrease in the pharmacological response of another drug
What are the 4 types of antagonism?
Physical -binds partial on surface (eg activated charcoal)
Chemical - chemical bond to drug (eg EDTA and lead)
Physiological - antagonize effect of drug; not the mechanism; acts on a different receptor (eg epinephrine and histamine)
Pharmacological -acts on the same receptor/mechanism
What are the two types of pharmacological antagonism?
Competitive- reversible binding; concentration dependent (e.g. atropine and ACh)
Noncompetitive- irreversible binding; not concentration dependent; time dependent (e phenoxybenzamine and epinephrine)
What are pharmacodynamic interactions by two drugs
Two drugs act on the same receptor
What are pharmacokinetic interactions between two drugs
Alter
- absorption
- distribution
- biotransformation
- excretion
How can a drug alter absorption of another drug
Inhibit or enhance
Calcium binds tetracycline = inhibit absorption
Epinephrine subcutaneously inhibits systemic absorption of local anesthetic
How can a drug alter the distribution of another dug?
Strongly bound drugs to plasma proteins (eg phynylbutazone/aspirin) displaces weakly bound dugs (eg warfarin) => more free drug => more effect
Enzyme___________ may decrease the effects of other drugs
Inducers
Increased biotransformation
Eg phonobabital is an enzyme inducer
Enzyme _____________ may increase the effects of other drugs
Inhibitors
Decreased biotransformation
Eg chloramphenicol is an enzyme inhibitor
What will enhance the renal excretion of weak acidic drugs?
Urinary alkalinizers
Sodium bicarbonate
What will enhance renal excretion of weak basic drugs ?
Urinary acidifiers
Ammonium chloride
______________ inhibits tubular secretion of penicillin G by competing on the carrier molecule
Probenecid
What are examples of drug incompatibility
Vit B compels with many solutions of antibiotics
Xylazine with thiopental
Tetracycline with calcium
Sodium bicarbonate with epinephrine
What environment factors can affect drug response?
Ambient temperature
Humidity
Oxygen
