Factors Modifying Drug Dose and Response Flashcards
What are the factors related to the animal?
1: Species, breed, individual
2: Body weight, age, sex, temperament
3: Idiosyncrasy
4: Hypersensitivity
5: Disease
6: Tolerance
What are the factors related to the drug?
1: Route and timing of administration
2: Cumulation
3: Drug-drug interaction
What are the factors related to the environment?
1: Ambient temperature
2: Humidity
3: Oxygen
4: Exposure to light
What are the species differences?
1: Anatomic
2: Physiologic
3: Biochemical
What are the anatomical differences?
Digestive tract of ruminants vs. non-ruminants
What are the physiological differences?
1: Salivary enzymes
2: Urine pH
What are the biochemical differences?
1: Metabolic
2: Plasma protein binding
3: Presence of receptors
True or false: Cats have salivary amylase.
False
Cat urine is more _____.
Acidic
Dog and horse urine is more _____.
Basic
True or False: Cats are deficient in certain drug-metabolizing enzymes.
True
What is the pH of the rumen?
~6.0pH
What is the pH of the monogastric stomach?
~2-3pH
Which type of breeds are more sensitive to many drugs?
Herding breeds (Collies, sheepdogs, etc…)
What drug is a class example of herding breed sensitivity?
Ivermectin
Which type of dogs are sensitive to phenothiazines?
Brachycephalic (boxers, bulldogs, pugs, etc…)
True or False: Severe dehydration causes a decrease in weight.
True
Newborn and pediatric animals have what factors that need to be considered?
Decreased metabolism, excretion, plasma protein binding, blood-brain barrier function.
Increased total body water
Growth and susceptibility to adverse drug effects
Geriatric animal have what factors that need to be considered?
Decreased metabolic enzymes, hepatic blood flow, renal function, cardiac output, total body water, plasma protein, lean body mass.
Increased body fat, distribution
Presence of chronic disease
What sex factor affect drugs?
1: Females have a greater fat to lean body mass compared to mature males
2: Pregnancy increases the volumes of distribution
3: Lactation leads to some drugs being trapped in the milk
How does aggression affect drug dosage?
Higher dosage may be needed when using sedative and tranquilizers
How does docility affect drugs dosage?
May not require full dose sedation in some cases
What is an idiosyncratic drug reaction?
An individual drug sensitivity
Define idiosyncratic reactions.
Uncommon genetically determined and unpredictable abnormal drug responses.
True or False: Idiosyncratic drug reactions are dose-dependent.
False
What is a drug hypersensitivity reaction?
An allergic drug reaction.
Drugs in a hypersensitivity reaction can act as _____ or _____.
Antigens
Haptans
Prior exposure to drugs that act like _____ is required to cause a hypersensitivity reaction.
Antigens
What happens with hepatic dysfunction?
1: Can’t metabolize most drugs normally
2: Decreased drug metabolism
What happens with renal insufficiency?
1: Can’t excrete most drugs via the kidney and into the urine normally
2: Decreased drug excretion
What happens in congestive heart failure?
1: Can’t pump drugs to the site of action, metabolism, or excretion normally.
2: Decreased renal excretion
Define drug tolerance.
An unusual resistance to ordinary drug dose
What are the types of tolerances?
1: Natural
2: Acquired
3: Cross
4: Tachyphylaxis
Define cross-tolerance.
Drugs in the same class
Define tachyphylaxis tolerance.
Acute acquired tolerance
What are the factors related to the drug?
1: Route of administration
2: Timing of administration
Define accumulation.
Occurs when the ate of elimination is slower than rate of absorption.
Drug accumulation can be modified due to _____.
Factors related to the animal
Define drug-drug interactions.
The administration of drugs concurrently or sequentially
What are the types of drug-drug interactions?
1: Summation
2: Potentiation
3: Synergism
4: Antagonism
What is summation?
Effects of the drugs are added together
What happens in potentiation?
Intensification of drug effects
What happens in synergism?
Exaggeration of drug effects
What happens in antagonism?
Drug decreases effect of another drug
What happens in pharmacokinetics?
1: Absorption
2: Distribution
3: Biotransformation
4: Excretion
What happens in pharmacodynamics?
1: Drugs act on the same receptors
2: Drugs act on different receptors
What are the types of drug incompatibility?
1: Physical
2: Chemical
What are the environmental factors that effect drugs?
1: Ambient temperature
2: Humidity
3: Oxygen
4: Exposure to light
