Pharmacology Ii Exam 3

Front 1

Why do most abscesses in reptiles require surgical debridement in addition to treatment with antimicrobials?

Back 1

Reptiles form caseous abcesses that are not easily penetrated by antimicrobials, and cannot be drained.

Front 2

What are the most common diseases requiring antimicrobial therapy in turtles?

Back 2

Otitis media-mixed gram neg.
Shell necrosis-mixed bacterial and fungal

Front 3

What are the most common diseases requiring antimicrobial therapy in crocodilians?

Back 3

Bacterial pneumonia
Bacterial dermatitis

Front 4

What are some considerations to keep in mind when selecting antimicrobial agents for treating reptiles?

Back 4

1. Identify the causative agent-often mixed bacterial infections of primarily gram negatives.
2. Bacterial granulomas must be surgically removed.
3. Bactericidal drugs are best-patient is often already immunocompromised.
4. Route and frequency of administration, especially in dangerous species.
5. Ability of drug to be diluted to appropriate dose.
6. Volume of drug to be given-hard to give large amounts to small reptiles.

Front 5

Why is uptake and distribution of antimicrobial agents not reliable when given orally to reptiles through a meal (ie. give mouse the meds, feed mouse to snake).

Back 5

Transit time varies between species. By the time the meal is consumed and digested, the drug may have been metabolized by the animal that was fed to the patient.

Front 6

When do you use topical ocular medications, and when is it best to use systemic medications to treat ocular disease?

Back 6

Topical-preferred route, gives high local concentration with fewer systemic side effects. Used for conjunctival, corneal, and anterior chamber disease, and glaucoma.
Systemic-used for deep intraocular penetration, when additional efficacy is needed for surface disease, or if the globe is perforated. Used almost exclusively in LA ($$) and snakes (topicals cannot penetrate spectacle scale)

Front 7

What guides choosing ocular drops vs. ocular ointments?

Back 7

Ointments-used when longer contact time is needed.
Drops-used if there is a possibility of globe perforation. The ointment vehicle can cause uveitis.
Availability of drop vs ointment formulation may also affect choice.

Front 8

How much of a drop or ointment should be put into the eye at each treatment? And what guidelines are there for giving multiple eye medications at once?

Back 8

Drops-only one drop is needed, more will cause excessive tearing and wash the medication away faster.
Ointment-1/4" stream. More is not any better, and can be wasteful/expensive.
Drops should be given before ointments; wait 5 minutes between adminstering different drops; multiple ointments can be given with no wait time.

Front 9

What is the purpose of vaccination?

Back 9

Prevention of disease from infectious agents, not prevention of the infection itself.

Front 10

What is the immunologic target of vaccines? What is the goal of stimulating these cells?

Back 10

Target is lymphocytes (B, Tc, and Th).
Goal is to stimulate the production of memory cells, not the production of antibody producing cells.

Front 11

What are the advantages and disadvantages of passive immunization?

Back 11

Advantages: Provides immediate protection.
Disadvantages: Short-lived protection, delays ability to vaccinate, may cause allergic reactions.

Front 12

What are some considerations that should be made when designing vaccines?

Back 12

Need for humoral vs. cellular immunity
Role of memory cells-incubation time of the disease
Should be inexpensive, stable, adaptable to mass vaccination, and confer strong and long lasting immunity, minimal side effects.

Front 13

What are some types and characteristics of noninfectious vaccines?

Back 13

Types: Inactive or killed pathogen; may be whole organism, subunit vaccine, recombinant protein vaccines, or peptide vaccines.
Characteristics: Requires adjuvant to stimulate local inflammation or there will be no response to the vaccine. Requires multiple inoculations. Primarily stimulates humoral response.

Front 14

What are the advantages and disadvantages of noninfectious vaccines?

Back 14

Advantages: No reversion to virulence; safe for pregnant, debilitated, or immunosuppressed individuals; will not cause disease.
Disadvantages: Primarily humoral response, minimum of 2 doses, shorter duration of immunity, higher antigen mass required ($$).

Front 15

What are some types and characteristics of live vaccines?

Back 15

Types: Attenuated whole organism (multiple mutations), deletion mutants (virulence gene removed), recombinant vectors (non-pathogenic virus with antigen gene inserted), DNA vaccines (gene innoculated beads allow DNA to be taken up into the cell and expressed).
Characteristics: Stimulates humeral and cellular mediated response, pathogen loses virulence while maintaining the ability to replicate (reduces innoculation dose), single innoculation may be effective.

Front 16

What are the advantages and disadvantages of using a live vaccine?

Back 16

Advantages: Stimulates both arms of the immune response. Provides long lasting immunity, usually with a single dose. Recombinant vectors may have the ability to overcome maternal immunity.
Disadvantages: Mutated vaccines may have the ability to revert to virulence (rare). Lower stability. Risk to immunocompromised and pregnant individuals. Easier to contaminate, must be used within hours of reconstituting.

Front 17

What factors may lead to vaccine failure?

Back 17

Host: Maternal immunity (most common), immunosuppression, genetic inability to respond.
Vaccine: Ineffective route of administration, antigenic variant no present in vaccine, poor vaccine design.
Human error: Improper selection, storage, preparation, or administration.

Front 18

What is the most common adverse vaccine reaction in small animals?

Back 18

Hypersensitivity reactions.
These are most common in young animals, and small breed dogs.

Front 19

What is the suspected cause of vaccine associated sarcomas in cats?

Back 19

Adjuvanted vaccines.

Front 20

What ages are considered too young or too old to vaccinate?

Back 20

Young: <4 wks, vaccine may cause disease. If failure of passive transfer is suspected use killed vaccines.
Old: No specific age, but animals with concurrent disease or immunesuppression should not be vaccinated. It is likely that most animals who have received vaccinations previously probably still have full protection. Best to consider risk of exposure, or legality (rabies).

Front 21

What is the ideal separation time between initial vaccination boosters? If this interval is overextended should the vaccine series be restarted?

Back 21

Ideal interval is 2-4 weeks, but if a longer interval is taken, there is no need to restart the series.

Front 22

Is serology useful?

Back 22

Yes and no. Because of varying methodologies, a specific titer number does not actually mean anything. Titers do not indicate the presence of CMI or memory cells. However, if there is a detectable titer, it is likely that that animal has adequate immune function capable of responding to the disease.

Front 23

Why does allometric scaling not always work appropriately for determining drug doses in birds?

Back 23

Differences in anatomy and physiology (eg. multiple nephron types, lower hepatic P450 pathways) may negate a correlation between absorption, biotransformation, distribution, and clearance/excretion.

Front 24

What are the requirements that must be fulfilled before using a drug extra label in bird and small mammal species?

Back 24

1. Reasonably investigate characteristics of use in other species.
2. Contact individuals with expertise using the drug in the species of interest.
3. If no record can be found of previous use, use with extreme caution.
4. Notify owners of the risk of use.

Front 25

What legislation allows for extra label use of drugs in avian and small mammals without prior study of the drug's use in that species?

Back 25

Minor Use in Minor Species Animal Health Act (MUMS):
-Provides a legal basis for using drugs in exotic pets.

Front 26

When is it still important to consider the legality of using extra label drugs in exotic pet species?

Back 26

Pet rabbits and pet chickens that may still be used for food if treatment fails.

Front 27

Which antimicrobial agents should you avoid giving orally to small mammals? Why?

Back 27

PELT-C:
1. Penicillins (Amoxy, clavamox)
2. Erythromycin
3. Lincomycine
4. Tetracycline
5. Cephalosporins
In hindgut fermenters (rabbits, chinchillas, guinea pigs), these drugs will cause dysbiosis and can result in enterotoxemia. They may be safe to give orally in non-fermenters such as ferrets.

Front 28

Treatment for aspergillosis in birds.

Back 28

1. Itraconazole (10 mg/kg, q24 hr). Toxic in African Grey parrots.
2. Voriconazole (15 mg/kg, q 12 hrs; or 25 mg/20 mL saline nebulizer). Not toxic in African Grey parrots. Expensive!
3. Amphotericin B-works well intratracheally.
4. Fluconazole-if CNS involvement.

Front 29

Treatment for Chlamydophila psittaci in birds.

Back 29

1. Doxycycline-orally, IM, or SQ, for 45 days. Dose varies by species.
2. Azithromycin-orally 40mg/kg, q48 hours for 21 days.

Front 30

Treatment for Pasteurellosis in rabbits.

Back 30

1. Baytril
2. Trimethoprim Sulfas
3. Chloramphenicol
4. Procaine + Benzathine Penicillins (inj).
Therapy must continue long term to clear the infection.

Front 31

Treatment for Helicobacter in ferrets.

Back 31

1. Amoxicillin, Metronidazole, and Bismuth subsalicylate. Amoxy and Metro must be used in combination to prevent drug resistance.
2. Clarithromycin, metronidazole, ranitidine, and omeprazole.

Front 32

Treatment for Mycoplasma in rats

Back 32

1. Enrofloxacine and Doxycycline
2. Azithromycine in refractory cases.
Environmental hygiene is an absolute must in curing these cases, otherwise reinfection will occur from environmental contamination.

Front 33

What is the definition of a drug-drug interaction?

Back 33

Altered pharmacokinetic (concentration-time profile) or pharmacodynamic (concentration-effect profile) response to one drug caused by the presence of a second drug.

Front 34

Consequence of drug-drug interactions due to protein-binding displacement.

Back 34

Under most senarios, changes in free fraction are not clinically relevant, and often the free fraction is not changed even when the total bound fraction is reduced.

Front 35

Consequences of drug-drug interactions due to hepatic metabolism.

Back 35

1. Inhibition of metabolism-increases toxicity or side effects of the affected drug. This occurs rapidly.
2. Induction of metabolism-increased clearance reduces efficacy, may also increase toxicity if a toxic metabolite is produced from the effected drug. This occurs slowly.

Front 36

When are hepatic metabolism drug-drug interactions most important?

Back 36

When the affected drug has a narrow theraputic index.

Front 37

List 5 common drug-drug interactions, and which drug is affected and how.

Back 37

1. Chloramphenicol/Phenobarbitol-double interaction. Increased clearance of chlormaphenicol and decreased clearance of phenobarbitol.
2. Theophilline/enrofloxacin-decreased clearance of theophilline.
3. Corticosteroids/NSAIDs-overlapping GI toxicity. Steroids may increase clearance of Aspirin.
4. Ketoconazole/cyclosporine-increased cyclosporine concentrations.
5. Cimetidine/Theophilline-increased theophilline concentrations.

Front 38

What can be done to decrease the risk of drug-drug interactions?

Back 38

1. Predict whether an interaction will occur: Keep a list of common inducers/inhibitors/substrates, consider dose and length of treatment (will induction occur before drug combo is stopped), consider theraputic index (large TI, probably not going to be an issue), use TDM if available, INFORM THE CLIENT of possible risks.
2. Evaluate the severity of the interaction: Based on studies, if >20-25% change, probably clinically significant. Clearance (IV drugs) and Bioavailablity (PO drugs) are the most important parameters to consider.
3. Act accordingly: Some interactions are useful, some should be avoided at all costs, and some can be used with dose adjustments.

Front 39

What is the most common synergistic antibiotic interaction?

Back 39

Beta-lactams and aminoglycosides

Front 40

What are the primary objectives of using antimicrobial combinations?

Back 40

1. Polymicrobial infections
2. Reduce emergence of resistant bacteria
3. Decrease dose-related toxicity
4. Increase chance of organisms susceptibility
5. Synergy

Front 41

What conclusions can be drawn from studies of antimicrobial synergy?

Back 41

Combinations are only advantageous in certain settings (eg. specific organisms or strains).
In vitro synergy cannot be assumed to straightforwardly occur in vivo (may be affected by tissue conditions, etc).

Front 42

Support or refute the following statements:
We use antimicrobials because:
1. They may have an infection
2. They may get an infection
3. Antibiotics are safe so they won't hurt

Back 42

1. True, but the infection may not be bacterial, or the process may be inflammatory but not infectious.
2. True but irrelevant-depends on the underlying infection, patient's immune status, and potential for exposure.
3. True but not completely. Most have at least mild side effects,f they don't help there is no reason to use, and unnecessary use may contribute to resistance.

Front 43

What tests can be used to increase your clinical suspicion of bacterial infection?

Back 43

Clinical signs: Fever, pain
CBC: leukocytosis +/- left shift, toxic change.
Chem: Signs of organ dysfunction
Culture, Gram stain, Cytology!-only way to truly confirm a bacterial infection.