Penn Foster Veterinary Pharmacology
Complete Course Review
100 Comprehensive Q&A – Learning
Framework & Key Concepts
Section 1: Pharmacology Fundamentals & Principles (Q1-15)
1. What is the primary difference between pharmacokinetics and pharmacodynamics?
Answer: Pharmacokinetics is "what the body does to the drug" (absorption, distribution,
metabolism, excretion). Pharmacodynamics is "what the drug does to the body" (mechanism of
action, effects).
2. Define the term "bioavailability" in pharmacokinetics.
Answer: The fraction of an administered drug that reaches systemic circulation unchanged
and becomes available to produce its effect.
3. What does the term "half-life" (t½) of a drug refer to?
Answer: The time required for the plasma concentration of a drug to decrease by 50%.
4. Explain the concept of "therapeutic index" and its clinical significance.
Answer: The ratio between a drug's toxic dose and its therapeutic dose (LD50/ED50). A high
TI indicates a safer drug; a low TI requires close monitoring.
5. What is the first-pass effect?
Answer: The metabolism of an orally administered drug in the liver via the portal circulation
before it reaches systemic circulation, reducing its bioavailability.
6. Which law governs the prescription of controlled substances in veterinary medicine?
Answer: The Controlled Substances Act (CSA), enforced by the DEA. Veterinarians must
register and maintain strict records (Schedules II-V).
7. What does "extra-label drug use" (ELDU) mean under the Animal Medicinal Drug Use
Clarification Act (AMDUCA)?
, Answer: The use of an FDA-approved drug in a manner not specified on the label (different
species, dose, route, condition) by a veterinarian within a valid VCPR.
8. Define "withdrawal time" in veterinary pharmacology.
Answer: The time between the last dose of a drug administered to a food animal and when
its tissues (meat, milk, eggs) can be legally harvested for consumption (residue avoidance).
9. What is the main purpose of the "Veterinary Feed Directive" (VFD)?
Answer: To regulate the use of medically important antimicrobials in animal feed, requiring
veterinarian authorization (prescription) to ensure judicious use.
10. What are the four main stages of pharmacokinetics?
Answer: Absorption, Distribution, Metabolism, Excretion (ADME).
11. What does CYP450 refer to in drug metabolism?
Answer: The Cytochrome P450 enzyme system, primarily in the liver, responsible for
metabolizing many drugs (Phase I reactions).
12. What is a "prodrug"?
Answer: An inactive drug form that requires metabolism in the body to become
therapeutically active.
13. How does protein binding affect drug distribution?
Answer: Only the unbound (free) fraction of a drug is pharmacologically active and can
distribute to tissues. High protein binding can limit availability and prolong half-life.
14. What is the primary site of drug excretion for most agents?
Answer: The kidneys (via urine). Other routes: liver/bile (feces), lungs, saliva, milk.
15. What is the meaning of "agonist" vs. "antagonist"?
Answer: An agonist binds to a receptor and activates it, producing an effect. An antagonist
binds to a receptor and blocks it, preventing an agonist's effect.
Section 2: Antimicrobials & Antiparasitics (Q16-35)
16. What is the mechanism of action of beta-lactam antibiotics (e.g., penicillins,
cephalosporins)?
Answer: Inhibition of bacterial cell wall synthesis by binding to penicillin-binding proteins
(PBPs).
,17. Why are aminoglycosides (e.g., gentamicin) considered concentration-dependent killers?
Answer: Their efficacy depends on achieving a high peak plasma concentration relative to
the pathogen's MIC. They have a post-antibiotic effect.
18. What is a common, serious side effect of systemic enrofloxacin in young, growing cats?
Answer: Retinal degeneration and blindness due to fluoroquinolone toxicity. Use with
caution; avoid high doses.
19. Which class of antibiotics is associated with immune-mediated hematologic reactions in
dogs, especially Doberman Pinschers?
Answer: Sulfonamides (e.g., trimethoprim-sulfa). Can cause thrombocytopenia,
neutropenia, polyarthritis.
20. What is the mechanism of action of tetracyclines?
Answer: Inhibition of bacterial protein synthesis by binding to the 30S ribosomal subunit.
21. What is the primary clinical use of metronidazole in veterinary medicine?
Answer: Treatment of anaerobic bacterial infections and certain protozoal infections (e.g.,
Giardia, Trichomonas). Also used for inflammatory bowel disease.
22. Which macrocyclic lactone is commonly used for heartworm prevention and treatment of
many ecto- and endoparasites?
Answer: Ivermectin. (Note: Collie breeds may have MDR1 gene mutation causing
sensitivity).
23. What is the main clinical sign of ivermectin toxicity in sensitive dogs?
Answer: CNS depression, ataxia, mydriasis, blindness, coma, and potentially death.
24. What class of antiparasitic drug is praziquantel, and what is its primary target?
Answer: Cestocide (and trematocide). It causes tegumental disruption and paralysis of
tapeworms (and flukes).
25. What is the mechanism of action of fenbendazole?
Answer: It binds to parasite tubulin, inhibiting microtubule formation, disrupting glucose
uptake, and leading to parasite death (broad-spectrum benzimidazole anthelmintic).
26. What is a key nursing consideration when administering topical flea preventatives (e.g.,
fipronil, imidacloprid)?
Answer: Ensure the animal is dry, part the fur for direct skin application, and prevent animal
grooming or human contact until dry.
, 27. What is the drug of choice for treating Babesia gibsoni infections in dogs?
Answer: Atovaquone and azithromycin combination therapy.
28. Which antifungal drug is considered nephrotoxic and requires monitoring of renal values
and hydration?
Answer: Amphotericin B.
29. What is the primary use of milbemycin oxime?
Answer: Heartworm prevention and treatment of various internal parasites (hookworm,
roundworm, whipworm) and external parasites (e.g., mites).
30. Why is fluconazole often preferred over ketoconazole for systemic fungal infections?
Answer: Fluconazole has better penetration into the CNS and urine, fewer side effects, and
less hepatotoxicity.
31. What is a major concern with the use of chloramphenicol in food animals?
Answer: It can cause fatal aplastic anemia in humans; therefore, it is banned in food animals
to prevent residues.
32. What does "MDR1 gene mutation" affect in veterinary pharmacology?
Answer: It results in a defective P-glycoprotein drug transporter, leading to increased
neurotoxicity from drugs like ivermectin, loperamide, and certain chemotherapeutics in affected
breeds (e.g., Collies).
33. Which antibiotic class should be avoided in juvenile animals due to cartilage
abnormalities?
Answer: Fluoroquinolones.
34. What is the mechanism of action of nitrofurans (e.g., nitrofurantoin)?
Answer: They are converted by bacterial enzymes to reactive intermediates that damage
DNA, RNA, and proteins.
35. What is the primary target parasite for emodepside?
Answer: It is highly effective against roundworms (ascarids) and hookworms by binding to
presynaptic latrophilin receptors.
Section 3: Anesthetics, Analgesics & CNS Drugs (Q36-55)
36. What is the reversal agent for benzodiazepines (e.g., diazepam, midazolam)?
Answer: Flumazenil.
Complete Course Review
100 Comprehensive Q&A – Learning
Framework & Key Concepts
Section 1: Pharmacology Fundamentals & Principles (Q1-15)
1. What is the primary difference between pharmacokinetics and pharmacodynamics?
Answer: Pharmacokinetics is "what the body does to the drug" (absorption, distribution,
metabolism, excretion). Pharmacodynamics is "what the drug does to the body" (mechanism of
action, effects).
2. Define the term "bioavailability" in pharmacokinetics.
Answer: The fraction of an administered drug that reaches systemic circulation unchanged
and becomes available to produce its effect.
3. What does the term "half-life" (t½) of a drug refer to?
Answer: The time required for the plasma concentration of a drug to decrease by 50%.
4. Explain the concept of "therapeutic index" and its clinical significance.
Answer: The ratio between a drug's toxic dose and its therapeutic dose (LD50/ED50). A high
TI indicates a safer drug; a low TI requires close monitoring.
5. What is the first-pass effect?
Answer: The metabolism of an orally administered drug in the liver via the portal circulation
before it reaches systemic circulation, reducing its bioavailability.
6. Which law governs the prescription of controlled substances in veterinary medicine?
Answer: The Controlled Substances Act (CSA), enforced by the DEA. Veterinarians must
register and maintain strict records (Schedules II-V).
7. What does "extra-label drug use" (ELDU) mean under the Animal Medicinal Drug Use
Clarification Act (AMDUCA)?
, Answer: The use of an FDA-approved drug in a manner not specified on the label (different
species, dose, route, condition) by a veterinarian within a valid VCPR.
8. Define "withdrawal time" in veterinary pharmacology.
Answer: The time between the last dose of a drug administered to a food animal and when
its tissues (meat, milk, eggs) can be legally harvested for consumption (residue avoidance).
9. What is the main purpose of the "Veterinary Feed Directive" (VFD)?
Answer: To regulate the use of medically important antimicrobials in animal feed, requiring
veterinarian authorization (prescription) to ensure judicious use.
10. What are the four main stages of pharmacokinetics?
Answer: Absorption, Distribution, Metabolism, Excretion (ADME).
11. What does CYP450 refer to in drug metabolism?
Answer: The Cytochrome P450 enzyme system, primarily in the liver, responsible for
metabolizing many drugs (Phase I reactions).
12. What is a "prodrug"?
Answer: An inactive drug form that requires metabolism in the body to become
therapeutically active.
13. How does protein binding affect drug distribution?
Answer: Only the unbound (free) fraction of a drug is pharmacologically active and can
distribute to tissues. High protein binding can limit availability and prolong half-life.
14. What is the primary site of drug excretion for most agents?
Answer: The kidneys (via urine). Other routes: liver/bile (feces), lungs, saliva, milk.
15. What is the meaning of "agonist" vs. "antagonist"?
Answer: An agonist binds to a receptor and activates it, producing an effect. An antagonist
binds to a receptor and blocks it, preventing an agonist's effect.
Section 2: Antimicrobials & Antiparasitics (Q16-35)
16. What is the mechanism of action of beta-lactam antibiotics (e.g., penicillins,
cephalosporins)?
Answer: Inhibition of bacterial cell wall synthesis by binding to penicillin-binding proteins
(PBPs).
,17. Why are aminoglycosides (e.g., gentamicin) considered concentration-dependent killers?
Answer: Their efficacy depends on achieving a high peak plasma concentration relative to
the pathogen's MIC. They have a post-antibiotic effect.
18. What is a common, serious side effect of systemic enrofloxacin in young, growing cats?
Answer: Retinal degeneration and blindness due to fluoroquinolone toxicity. Use with
caution; avoid high doses.
19. Which class of antibiotics is associated with immune-mediated hematologic reactions in
dogs, especially Doberman Pinschers?
Answer: Sulfonamides (e.g., trimethoprim-sulfa). Can cause thrombocytopenia,
neutropenia, polyarthritis.
20. What is the mechanism of action of tetracyclines?
Answer: Inhibition of bacterial protein synthesis by binding to the 30S ribosomal subunit.
21. What is the primary clinical use of metronidazole in veterinary medicine?
Answer: Treatment of anaerobic bacterial infections and certain protozoal infections (e.g.,
Giardia, Trichomonas). Also used for inflammatory bowel disease.
22. Which macrocyclic lactone is commonly used for heartworm prevention and treatment of
many ecto- and endoparasites?
Answer: Ivermectin. (Note: Collie breeds may have MDR1 gene mutation causing
sensitivity).
23. What is the main clinical sign of ivermectin toxicity in sensitive dogs?
Answer: CNS depression, ataxia, mydriasis, blindness, coma, and potentially death.
24. What class of antiparasitic drug is praziquantel, and what is its primary target?
Answer: Cestocide (and trematocide). It causes tegumental disruption and paralysis of
tapeworms (and flukes).
25. What is the mechanism of action of fenbendazole?
Answer: It binds to parasite tubulin, inhibiting microtubule formation, disrupting glucose
uptake, and leading to parasite death (broad-spectrum benzimidazole anthelmintic).
26. What is a key nursing consideration when administering topical flea preventatives (e.g.,
fipronil, imidacloprid)?
Answer: Ensure the animal is dry, part the fur for direct skin application, and prevent animal
grooming or human contact until dry.
, 27. What is the drug of choice for treating Babesia gibsoni infections in dogs?
Answer: Atovaquone and azithromycin combination therapy.
28. Which antifungal drug is considered nephrotoxic and requires monitoring of renal values
and hydration?
Answer: Amphotericin B.
29. What is the primary use of milbemycin oxime?
Answer: Heartworm prevention and treatment of various internal parasites (hookworm,
roundworm, whipworm) and external parasites (e.g., mites).
30. Why is fluconazole often preferred over ketoconazole for systemic fungal infections?
Answer: Fluconazole has better penetration into the CNS and urine, fewer side effects, and
less hepatotoxicity.
31. What is a major concern with the use of chloramphenicol in food animals?
Answer: It can cause fatal aplastic anemia in humans; therefore, it is banned in food animals
to prevent residues.
32. What does "MDR1 gene mutation" affect in veterinary pharmacology?
Answer: It results in a defective P-glycoprotein drug transporter, leading to increased
neurotoxicity from drugs like ivermectin, loperamide, and certain chemotherapeutics in affected
breeds (e.g., Collies).
33. Which antibiotic class should be avoided in juvenile animals due to cartilage
abnormalities?
Answer: Fluoroquinolones.
34. What is the mechanism of action of nitrofurans (e.g., nitrofurantoin)?
Answer: They are converted by bacterial enzymes to reactive intermediates that damage
DNA, RNA, and proteins.
35. What is the primary target parasite for emodepside?
Answer: It is highly effective against roundworms (ascarids) and hookworms by binding to
presynaptic latrophilin receptors.
Section 3: Anesthetics, Analgesics & CNS Drugs (Q36-55)
36. What is the reversal agent for benzodiazepines (e.g., diazepam, midazolam)?
Answer: Flumazenil.
