EXAM I Flashcards
T/F. Drugs that enter the GI system may interact with material in GIT, get into intestinal juice, be carried through the GI tract, interact with GI microbes, reach systemic circulation.
True
T/F. Ionization depends on the pKa of the drug and the pH of the medium.
True
What are the factors related to drug that affect drug absorption? What are the factor related to animals that affect drug absorption?
Drug: molecular size (small moves easily), disintegration and dissolution (lipid, powder, tab), lipid solubility, degree of ionization, concentration at absorptive site, route of administration
MUCOSAL IS THE FASTEST AND ORAL IS THE SLOWEST
Animals: blood flow (great absorption with greater blood flow), absorbing SA, CT, species, individual variation, fasted vs fed.
How is drug response quantified? What are the seven factors involved in this?
Measured and will typically give a curve (sigmoidal curve, straight portion between 20%-80% > therapeutic range)
Efficacy, Potency, Effective Concentration 50%, Effective Dose 50%, Therapeutic index is the LD50:ED50, Onset of action, Duration of action
What are the four common routes to undergo absorption to get from the site of administration to the bloodstream?
Enteral, Parenteral, Transdermal, and respiratory absorption
What are the FOUR mechanisms of “Transport across cell membrane”?
Simple/passive diffusion, facilitated diffusion, active transport, pinocytosis
T/F. Membranes are more permeable to ionized forms of drugs than non-ionized forms.
False. More permeable to non-ionized forms.
What is NOT a characteristic of BBB?
A. Right junctions between capillary endothelial cells and glial cell (force drugs to cross cell membrane to enter).
B. CSF is produced once in lifetime.
C. Active transport (P-gp) is responsbile for drug efflux out of the CNS.
D. If a drug crosses BBB, it can cross placental barriers.
B. CSF is produced once in lifetime.
Constantly produced and drains out of venous circulation (diluting things that do come through)
What is bioinactivation? What is bioactivation and what are the components?
Bioinactivation: not biologically active format
Bioactivation: can be inactive drug (prodrug) to active metabolite or active drug (parent drug) to active metabolite or nontoxic to toxic metabolites (lethal synthesis > oragnophosphate insecticide)
What are the five factors related to animal species?
Anatomical, Physiological, Biochemical, Behavior, Pharmacodynamic, Ectotherms (cold-blodded animals) vs mammals
Match the correct terms.
A. Summation B. Synergism C. Antagonism
- Additive effect: Drug A + Drug B > A+B
- Drug A + Drug B
- Additive effect: Drug A + Drug B = A+B
1 - B
2 -C
3 - A
What are the two outcomes of metabolism?
Physiocochmecial properties and phamacological activity
T/F. Large Vd indicates that the drug is not being distributed to all tissues of the body (drugs remain mostly in the plasma). Small Vd indicates that the drug is distributed somewhere or sequestered.
False.
Small Vd: stays in plasma
Large Vd: distributed to peripheral tissues/sequestered
Which drug are collies sensitive to?
ivermectin
Which of the following is NOT a characteristic of simple/passive diffusion?
A. Paracellular movement (intercellular aqueous channels; specialized intercellular junctions).
B. Transmembrane movement (diffusion through lipid membrane and aqueous protein channels; bulk flow due to osmotic or hydrostatic differences)
C. Movement with a concentration gradient (from high to low).
D. Lipid/water partition coefficient: relative solubility of a drug in lipis compared to water.
E. Diffusion coefficient: Carrier and channel mediated.
E. Diffusion coefficient: Carrier and channel mediated.
Diffusion coefficient: diffusional mobility of a partical molecule (molecular size, molecular conformation, degree of ionization).
T/F. Ion trapping: weak acids are absorbed form an acidic environment and sequestered in an alkaline medium. Weak bases are absorbed from an alkaline environment and sequestered in an acid medium.
TRUE
Why do you have to consider using a lower dose of lipophilic drugs in obese patients?
Redistribution into fat (stays longer in the system, therefore, overdose may occur)
Which of the following is NOT a characteristic of active transport?
A. Carrier-mediated transport.
B. Saturable and movement against a concentration gradient.
C. Requires energy.
D. Primary active transport uses energy directly from ATP and consists of symporters and antiporters.
E. Secondary active transport uses stored energy (Na+ electrochemical gradient).
D. Primary active transport uses energy directly from ATP and consists of symporters and antiporters.
Uses energy directly from ATP BUT symporters and antiporters are Secondary Active Transport characteristics.
What are the three ways to administer drugs for parenteral route?
IM, SC, IP
Which of the following is INCORRECT about Effective Dose 50%?
A. Dose that produces a result (maximal effect) in 50% of the animals
B. in VIVO, observed effect
C. LD50 is the dose which kills 50% of animals (effect is death)
A. Dose that produces a result (maximal effect) in 50% of the animals
DESIRED EFFECT, not maximal effect!
What is drug displacement?
Knocking off of from its binding site on albumin space (phenylbutazone and warfarin in horses)
T/F. Proteins that are embedded on cell membrane will sink or float, depending on theri characteristics. Tachyphylaxis may happen due to proteins sinking, leaving with a few receptors to being to drugs.
True.
T/F. Only the free drug is active and the normal dosing and disposition are predicted based on the expected degree of protein binding.
True
What is NOT a correct statement about tubular reabosorption for excretion?
A. Involves proximal and distal convoluted tubules.
B. Active diffusion in distal tubules and time dependent of pinocytosis.
C. Reabsorption of lipid-soluble and non-ionized drugs.
D. Fluids and diuretics enhance drug renal excretion by reducing the time for reabsorption.
B. Active diffusion in distal tubules and time dependent of pinocytosis.
Passive diffusion in distal tubules and concentration dependent of pinocytosis
What is the difference between side effects and adverse effects?
Side effects: effects secondary to the one intended (good or bad)
Adverse effects: unintended and uninvited; failure to produce the expected clinical effect
Which drug are boxers sensitive to? What is the adverse effect of the drug?
Phenothiazines
Adverse cardiovascular effects.
Which of the following is NOT a characterstic of transdermal absorption?
A. Impermeable to aqueous solutions
B. Stratum corneum is the rate limiting barrier
C. available in “spots-on” and “pour on”
D. As temperature increases, drugs have a lower effect on the body
E. Fentanyl formulation does not use a patch
D. As temperature increases, drugs have a lower effect on the body
As temperature increases, drugs have a higher effect on the body
State percentage up to 5 half-lives. What does 5 half-life indicate?
1 half life: 50% gone
2 half life: 75% gone
3.3 half life: 90% gone
5 half life: 97% (unlikely to have any more effect)
What is steady state concentration? What is the difference between interval dosing and loading dose?
Plasma drug concentration at steady state (concentration has reached equilibrium); drug going in=drug going out.
Interval dosing: peak - highest concentration at each dose; trough - lowest concentration at each dose; measure levels of therapeutic drug monitoring (TDM)
Loading dose: single dose to get the plasma concentration to a certain level and start repeated dosing at maintenance rate.
Which of the statement is INCORRECT?
A. Oral cavity: sublingual absorption, bypasses portal vein.
B. Esophagus and agandular stomach: minimal absorption.
C. Glandular stomach: some absorption (Gastric emptying time determines rate of absorption)
D. Small intestine: primary site of absorption.
E. No drugs should be activated in colon to retain lower GI tract microflora.
E. No drugs should be activated in colon to retain lower GI tract microflora.
Some drugs cna be activated (antibiotics) so then drugs are not exposed to lower GI tract microflora.
T/F. High hepatice extraction rati with oral medication will work well in the body (high first pass metabolism).
False.
WILL NOT work well because drugs cannot get to where it needs to go (metabolized already in the liver)
What is an example of biochemical differences for species differences?
Metabolic enzymes: cats
Deficient in glucuronyl transferase, therefore, alter metabolism of drugs.
Which of the following is NOT a characteristic of plasma protein binding? (Choose 2)
A. Basic drugs bind primarily to albumin (alpha drug to other proteins)
B. Binding is generally reversible and a satruable process
C. Bound drug is generally inactive
D. Species differences can occur
E. May be a concentration depedent dose
F. disease may modify protein binding
G. The more highly protein bound a drug is, the less significant changes in protein binding
A. Basic drugs bind primarily to albumin (alpha drug to other proteins)
Acidic drugs bind to albumin; basic drugs to other proteins.
G. The more highly protein bound a drug is, the less significant changes in protein binding
the MORE significant minor changes
What are the main routes to excrete drugs? What are other routes?
Renal (most) and hepatic
Feces (bile, non-absorbed drugs given orally, plasma to GIT), Milk/Egg (weak basic drugs ion trapped in milk, drug residues, suckling animal effects), Expired air, sweat, saliva, hair/feathers
T/F. Two compartment open model has central compartment (plasma/blood) and peripheral compartment (other tissues).
True
What are the characteristics of idiosyncratic drug reactions? Give two examples.
Unpredictable, Genetic, Uncommon, NOT dependent on dose, drug withdrawal, caused by reactive drug metabolites
Griseofulvin: liver damage in cats (acute hepatitis)
Methimazole: facial itching in cats
What is total renal excretion of a drug?
Filtration rate + secretion + reabsorption
What is drug disposition? What are the FOUR processes that are involved in this?
Study of movement of drugs across biological membrane in the body from the time of absroption until elimination.
ADME (absorption, distribution, metabolism, excretion)
T/F. Lidocaine
Given perineurally induces antiarrhythmic. Given IV induces local anesthesia.
False.
Perineurally: local anesthesia
IV: antiarrhythmic
What is INCORRECT about drugs targeting for enzymes through non-receptors?
A. Drugs compete with the real substrate for binding to the enzyme (acetylcholinesterase inhibitors by binding to the active site of acetylcholinesterase)
B. Drugs act as false substrates that will lead to the formation of abnormal metabolites instead of active products.
C. Prodrugs where the drug nees to be metaolized to its active form.
D. None of the above.
D. None of the above.
Which of the following is CORRECT for older animals?
A. Increased metabolism and excretion
B. Increased cardiac output & hepatic blood flow
C. Increased lean body mass and decreased body fat.
D. Increased total body water.
E. Reduced plasma proteins
E. Reduced plasma proteins related to kidney or liver disease
Everything else is the opposite.
What is glycoprotein efflux pump (p-gp)? Which drug/species is this deficient in?
Drug transporter; removes drugs after being absorbed into specific cells or tissues.
Ivermectin in Collies (CNS toxicity): p-gp is deficient, therefore, cannot pump out drug.
What are the two phases of live metabolism of drugs?
Phase I: Nonsynthetic and Phase II: Synthetic
Which of the following is INCORRECT about Effective Concentration 50%?
A. The concentration at which a drug produces 50% of its maximal effect
B. Only applies in vivo preparations (we want to see the effect in animals)
C. Useful to compare the efficacy of different ligands (full agonists vs. partial agonists)
B. Only applies in vivo preparations (we want to see the effect in animals)
in VITRO (cannot get this kind of measurement in an animal!)
What is bioequivalence?
Different formulation of the same drug that are absrobed to a similar extend and rate
Similar AUC, Cmax, Tmax
What does it mean by cumulation? What is dissolution?
The rate of elimination is slower than the rate of absorption (digitalis, phenylbutazone, thiopental)
Dissolution: oral (absorbed in the body); IV (dissolving before giving it to the patient)
What is a ligand? What are the two outcomes of this?
Ligand: anything that binds to a recognition site (endogenous ligand); prevents other ligands to bind to that site.
Agonist: mimics the effect of the endogneous ligand.
Antagonist (neutral agonist): binds to the receptor but does nothing on its own (sits there and prevents anything else from binding, therefore, blocking the receptor).
What is pharmacokinetics? What is pharmacodynamics?
Pharmacokinetics: what the body does to the drug (mathematical models of quantitate the time course of drug disposition in man and animals).
Pharmacodynamics: What the drug does to the body (Effects of drugs and their mechanism of action in the body).
What is NOT a characteristic of topical usage?
A. Local use but can happen in number of places (can be systemic)
B. Minimal absorption into systemic circulation
C. Inflammation can increase the amount of drug absorbed
D. Steroids, antibiotics, chemoterapy are related to topical usage.
E. Do not need to worry about overdose since it is non-invasie.
E. Do not need to worry about overdose since it is non-invasie.
May overdose.