III - Antibacterial Agents Flashcards by Jessica Hanaumi

What are the four classes of antibacterial agents based on mechanism of action?

Cell wall synthesis inhibitors
Protein synthesis inhibitors
Antimetabolites
Nucleic acid synthesis inhibitors

How well did you know this?

Not at all

Perfectly

List the cell wall synthesis inhibitors (4 broad categories)

Penicillins
Cephalosporins
Other beta lactams
Glycopeptides

How well did you know this?

Not at all

Perfectly

What are the five families of penicillins?

Natural penicillins
Aminopenicillins
Anti-staph penicillins
Anti-pseudomonal penicillins
Beta lactamase inhibitor combinations

How well did you know this?

Not at all

Perfectly

2 natural penicillins

Penicillin V
Penicillin G

How well did you know this?

Not at all

Perfectly

2 aminopenicillins

Amoxicillin
Ampicillin

How well did you know this?

Not at all

Perfectly

4 anti-staph penicillins

Methicillin
Cloxacillin
Dicloxacillin
Oxacillin

How well did you know this?

Not at all

Perfectly

3 anti-pseudomonal penicillins

Ticarcillin
Piperacillin
Carbenicillin

How well did you know this?

Not at all

Perfectly

1 beta lactamase inhibitor combination

Amoxicillin clavulanate

How well did you know this?

Not at all

Perfectly

How are cephalosporins categorized?

1st, 2nd, 3rd generation

How well did you know this?

Not at all

Perfectly

List 4 1st generation cephalosporin drugs

Cefadroxil
Cephalothin
Cephalexin
Cefazolin

How well did you know this?

Not at all

Perfectly

List two second generation cephalosporin drugs

Cefaclor
Cefoxitin

How well did you know this?

Not at all

Perfectly

List four 3rd generation cephalosporins

Ceftiofur
Cefpodoxime
Cefovecin
Ceftriaxone

How well did you know this?

Not at all

Perfectly

Name one beta lactam

Imipenem-cilastatin

How well did you know this?

Not at all

Perfectly

One example of a glycopeptide

vancomycin

How well did you know this?

Not at all

Perfectly

Five categories of protein synthesis inhibitors

Tetracyclines
Aminoglycosides
Amphenicols
Macrolides
Lincosamides

How well did you know this?

Not at all

Perfectly

Name three tetracyclines

Tetracycline
Oxytetracycline
Doxycycline

How well did you know this?

Not at all

Perfectly

Name four aminoglycosides

Gentamicin
Amikacin
Tobramycin (ophthalmic)
Neomycin (topical)

How well did you know this?

Not at all

Perfectly

Name three amphenicols

Chloramphenicol
Florfenicol
Thiamphenicol

How well did you know this?

Not at all

Perfectly

Name five macrolides

Erythromycin
Tilmicosin
Azithromycin
Tylosin
Tulathromycin

How well did you know this?

Not at all

Perfectly

Name two Lincosamides

Lincomycin
Clindamycin

How well did you know this?

Not at all

Perfectly

Three categories of Antimetabolites (inhibitors of intermediate metabolism)

Sulfonamides
Folate reduction inhibitors
Potentiates sulfonamides

How well did you know this?

Not at all

Perfectly

Name two sulfonamides

Sulfadiazine
Sulfasalazine

How well did you know this?

Not at all

Perfectly

Name three folate reduction inhibitors

Trimethoprim
Ormetoprim
Pyrimethamine

How well did you know this?

Not at all

Perfectly

Name two Potentiates sulfonamides

Trimethoprim-sulfa
Ormetoprim-sulfadimethoxine

How well did you know this?

Not at all

Perfectly

List the Nucleic Acid Synthesis Inhibitors

1. Fluoroquinolones 2. Rifampin 3. Metronidazole

Name seven Fluoroquinolones

Enroflaxin Orbifloxacin Difloxacin Barbofloxacin Danofloxacin Ciprofloxacin Pradofloxacin

All beta lactams are considered _____.

Bactericidal

Beta lactams bind the ________ enzymes.

Bacterial transpeptidase Aka penicillin binding proteins

This drug binds precursors of peptidoglycans interfering with bacterial cell wall synthesis.

Vancomycin

Beta lactams - what are the two most important mechanisms of resistance to penicillins?

1. Enzymatic destruction by beta-lactamases produced by bacteria (cephalosporin lactam ring is more resistant) 2. Altered target (altered penicillin binding protein)

________ and _________ are NOT effective against Pseudomonas and Styaphylococcus.

Natural penicillins - penicillin V and G Amino penicillins - amoxicillin, ampicillin (Susceptible to beta lactamase)

Spectrum of Activity: Penicillins Gram + aerobic

Natural P Aminopenicillins Antipseudomonal

Spectrum of Activity: Penicillins Gram - aerobic

Natural P (limited) Aminopenicillins (better than NP) Antipseudomonal

Spectrum of Activity: Penicillins Gram + anaerobic

Natural P Aminopenicillins (slightly less than NP) Antipseudomonal

Spectrum of Activity: Penicillins Gram - anaerobic

Natural P (limited effect) Aminopenicillins (slightly less than NP) Antipseudomonal

Spectrum of activity: cephalosporins Gram + aerobic

1G - cefadroxil, cephalothin, cephalexin, cefazolin 2G (weak) - cefactor, cefotoxin, cefotetan 3G - ceftiofur, cefpodoxime, cefovecin, ceftazidime, cefotaxime extended gram negative (Antipseudomonal)

Spectrum of Activity: Cephalosporins Gram -

1G - (fair) 2G - greater than 1G 3G - slightly increased resistance to beta lactamases 3G - Antipseudomonal

Spectrum of activity: cephalosporins Gram + and - anaerobes

2nd generation - just these two Cefoxitin Cefotetan

Spectrum of activity: other beta lactams Aerobic, gram +/-

Imipenem Vancomycin

Spectrum of activity: other beta lactams Anaerobic gram +/-

Imipenem

These two drugs are often reserved for very resistant organisms in human patients, so veterinary use should be limited.

Vancomycin Imipenem

Imipenem-cilastatin-bactericidal ????? Slide 15/77

Beta lactams, in general, are very safe, but the most common adverse reaction is ____________.

Hypersensitivity - which can be life threatening

Some of the cephalosporins have been associated with _________ (very rare).

Renal failure

Any antibiotic can potentially alter ________, resulting in ____.

Normal flora of the GI tract Resulting in diarrhea

Any drug can potentially irritate the ___, causing ___.

Stomach and small intestine Vomiting / inappetence

Procaine penicillin G can cause a _______ reaction for up to _____ after injection.

Positive procaine test Two weeks

The glycopeptide vancomycin is only available in ____ form.

Injectable / IV

Rapid IV administration of Vancomycin causes ______.

A hypersensitivity type reaction (histamine release)

Vancomycin has occasionally been associated with what four types of toxicity?

Renal toxicity Ototoxicity Reversible thrombocytopenia and neutropenia

Is vancomycin approved for use in food animals?

NO - it is prohibited.

Sodium and potassium salts of penicillin are commonly used in ____ but have to be administered ___ /day.

Foals 4x/day

Procaine penicillin G is commonly used in:

Horses and cattle

Indications for benzathine penicillin G

Shipping fever complex: Strep, Staph aureus, Arcanobacterium pyogenes Blackleg: Clostridium chauvoei

Anti Staph penicillins are commonly used to treat:

Mastitis in dairy cattle

How are antipseudomonal penicillins used?

Ticarcillin IV to treat serious gram - infections in dogs Intrauterine in mares

Amino-penicillins are used to treat:

Horses (IV ONLY) Cattle (intramammary amoxicillin) Dogs Cats

The most commonly used first generation cephalosporins (2)

Cefadroxil Cephalexin

Oral bioavailability in horses for these two cephalosporin drugs is very low.

Cefadroxil and cephalexin - first generation

This first generation cephalosporin is formulated for dairy cattle.

Cephapirin

This first generation cephalosporin is used in dogs, cats, and horses, especially with orthopedic surgeries.

Cefazolin - penetrates bone; used prophylactically

These two second generation cephalosporins are used for abdominal surgical prophylaxis in dogs and cats.

Cefoxitin Cefotetan Because of their activity against gram- and some anaerobic organisms.

Ceftiofur, a third generation cephalosporin is labeled for treating:

UTI in cats and dogs (SQ) Respiratory infections in horses, cattle, and pigs

Cefovecin (Convenia) is a ___ generation cephalosporin used to treat:

3rd Skin infections in dogs and cats One-time injectable

This 3rd generation cephalosporin is administered daily to treat skin infections in dogs.

Cefpodoxime

These 3rd generation cephalosporins are not labeled for use in veterinary medicine but are occasionally used in dogs, cats, and foals for severe, resistant infections.

Carbapenems

Vancomycin is not labeled for use in veterinary medicine, and is illegal to use in food animals, but is occasionally used for:

Resistant Staphylococcal (MRSA) and/or Enterococcus infections in dogs, cats, and horses.

What are the five categories of protein synthesis inhibitors?

Tetracyclines Aminoglycosides Amphenicols Macrolides Lincosamides

Which protein synthesis inhibitors are bacteriostatic?

Tetracyclines Amphenicols Macrolides Lincosamides

Which protein synthesis inhibitors are bacteriocidal?

Aminoglycosides

Name three tetracyclines

Tetracycline Oxytetracycline Doxycycline

Name four aminoglycosides.

Gentamicin Amikacin Tobramycin (ophthalmic) Neomycin (topical)

Name three amphenicols

chloramphenicol Florfenicol Thiamphenicol

Name five macrolides

Erythromycin Tilmicosin Azithromycin Tylosin Tulathromycin

Name two Lincosamides

Lincomycin Clindamycin

Resistance to Lincosamides, macrolides, and amphenicols

Inactivation/degradation by bacterial enzymes

Resistance to tetracyclines

EFFLEX PUMP that transports the drug out of the bacterial cell; drug fails to reach its target; plasma encoded Resistance to one tetracycline produces cross resistance to others.

Resistance to aminoglycosides

Inactivation/degradation by bacterial enzymes Failure to reach target because of decreased porin size occurs in some gram - organisms.

These protein synthesis inhibitors are active against rickettsiaceae, mycoplasma anaplasmataceae, and chlamydia

Tetracyclines and amphenicols

Staph, Pseudomonas and E. Coli should be considered resistant to which protein synthesis inhibitors until proven otherwise?

Tetracyclines

GI side effects of protein synthesis inhibitor tetracycline

Anorexia Vomiting Diarrhea

In horses, IV administration of this tetracycline can be fatal.

Doxycycline

Permanent brown discoloration of teeth can occur if this protein synthesis inhibitor is administered during tooth development.

Tetracyclines

Rapid IV administration of _____ in many species has resulted in collapse possibly due to calcium chelation.

Tetracyclines

In addition to GI side effects, tetracycline can cause these four issues.

Drug-induced fever Renal toxicity Hepatotoxicity Allergic reactions

Cats are particularly prone to _______ caused by tetracyclines. Any dose should be followed by water.

Esophageal lesions (fibrosis and stricture)

Aminoglycosides have three main adverse effects:

Nephrotoxicity Ototoxicity Neuromuscular blockade

_____ concentrations are 50X greater in renal tissue than in plasma.

Aminoglycoside

Three ways to decrease nephrotoxicity with aminoglycosides.

1. Use least toxic - Amikacin 2. Do not use in hypovolemic patients 3. Avoid concurrent use of other nephrotoxic drugs (furosemide, NSAIDs)

Aminoglycoside Ototoxicity is ____.

irreversible

Aminoglycoside Ototoxicity can occur with ____ administration.

Topical or systemic

Optic administration of aminoglycosides should be avoided in patients with __.

A ruptured tympanic membrane

Auditory toxicity with aminoglycosides is more common in ___ and vestibular toxicity is more common in ___.

Auditory - dogs Vestibular - cats

Aminoglycoside toxicity induced neuromuscular blockade is __.

Reversible

Aminoglycosides can cause ___ in humans.

Irreversible aplastic anemia

Aminoglycosides can cause reversible ___ in dogs and cats.

Bone marrow suppression

Chloramphenicol inhibits ____ so can be involved in drug interactions.

CYP450 enzymes

____ was developed for use in food animals and has advantages over chloramphenicol.

Florfenicol

Name two advantages of florfenicol over chloramphenicol.

Florfenicol is not associated with aplastic anemia in people, so is not prohibited in food animals. Florfenicol does not inhibit CYP450 enzymes

Which aminoglycoside can cause severe diarrhea in horses?

Florfenicol

This macrolide frequently causes GI upset and vomiting thought to result from its interaction with the motilin receptor which stimulates GI motility.

Erythromycin Newer macrolides do not have this effect

Macrolides can cause __ in adult horses and __ in foals.

Severe colitis in adult horses Hyperthermia in foals

This macrolide can cause severe cardiovascular toxicity at high doses in cattle, and even at low doses can be fatal in swine, horses, goats, and people.

Tilmicosin Other macrolides do not share this adverse effect

Does Micotil 300, an injectable Tilmicosin drug, have an antidote?

In horses, ___ are generally not used because they can cause an overgrowth of Clostridium difficile resulting in severe pseudomembranous colitis.

Lincosamides

The most commonly used tetracycline in large animal veterinary medicine is ___.

Oxytetracycline

Oxytetracycline has been used for treating bovine ____, ___, and ____.

Bovine respiratory diseases Mastitis Anaplasmosis

Intrauterine infusion of ____ is used for cows with retained fetal membranes (off label).

Oxytetracycline

In horses, oxytetracycline has been used to treat ____.

Neorickettsia risticii (Potomac Horse Fever)

What is the most commonly used tetracycline in small animal veterinary medicine?

Doxycycline

Is doxycycline a good choice for UTIs?

No - unlike other tetracyclines, doxycycline does not achieve high concentrations in urine

Doxycycline is ____ and penetrates tissues well.

Lipophilic

This protein synthesis inhibitor is considered the drug of choice for treating intracellular pathogens such as Ehrlichiosis, Rickettsia, and Mycoplasma.

Doxycycline

Doxycycline is considered the drug of choice for treating intracellular pathogens such as ___, ___, and ____.

Ehrlichiosis Rickettsia Mycoplasma

What are the three most commonly used aminoglycosides in veterinary medicine?

Gentamicin Amikacin Neomycin

Three differences between the aminoglycosides gentamicin and Amikacin.

1. Amikacin is less susceptible to bacterial inactivation than gentamicin. 2. Amikacin is potentially less likely to produce nephrotoxicity. 3. Amikacin is more expensive than gentamicin.

Which aminoglycoside (protein synthesis inhibitor) is frequently used systemically in horses?

Gentamicin

Which aminoglycoside (protein synthesis inhibitor) is used in foals, dogs, and cats.

Amikacin

Which aminoglycoside (protein synthesis inhibitor) is used as an intrauterine infusion for horses?

Amikacin

Which aminoglycoside (protein synthesis inhibitor) is used for regional limb perfusion to treat lower limb bone and joint infections?

Gentamicin

Which protein synthesis inhibitors are lipid soluble?

Amphenicols

The amphenicols (protein synthesis inhibitors) are lipid soluble and therefore achieve high concentrations within ___ and can gain access to tissues such as ___.

Cells CNS, prostate

Chloramphenicol is used in small animals primarily for ___, some ___, and ___.

CNS infections Some rickettsiae Mycoplasma

This protein synthesis inhibitor is sometimes used in horses (has reasonable oral bioavailability and does not cause serious adverse effects on the GI flora) but is ILLEGAL for use in food animals.

Chloramphenicol

____ is approved for use as an injectable (IM or SQ) for treating bovine respiratory disease and bovine interdigital phlegmon (foot rot).

Florfenicol

Florfenicol (protein synthesis inhibitor) is approved for use as an injectable (IM, SQ) for treating bovine ___ and bovine ___.

Bovine respiratory disease Bovine interdigital phlegmon (foot rot)

These macrolides (protein synthesis inhibitors) are the three most commonly used in small animals and horses.

Erythromycin Azithromycin Clarithromycin

Because of its long tissue half-life in the respiratory tract, this protein synthesis inhibitor has an unusual dosing recommendation - once every three days or once a day for three days then stop.

Azithromycin (a macrolide)

Macrolides (protein synthesis inhibitors), particularly ____, are lipid soluble, and are therefore useful against susceptible ___.

Azithromycin Intracellular bacteria

In horses, both ___ and ____ are effective for treating Rhodococcus equi infections.

Clarithromycin Azithromycin

Which two macrolides are used in dogs and cats to treat a variety of respiratory infections?

Clarithromycin Azithromycin Also effective for treating Rhodococcus equi infections in horses

Macrolides are ____ inhibitors.

Protein synthesis

____ are approved for use as an injectable (IM/SQ) for treating bovine respiratory disease and bovine interdigital phlegmon (foot rot).

Macrolides (protein synthesis inhibitors) - Gamithromycin - Tulathromycin - Tilmicosin

This macrolide may have direct or indirect immunologic properties and may reduce antigenic stimulation in treating dogs with IBD.

Tylosin (Macrolide / Protein Synthesis Inhibitor)

T/F Considering the role of altered antigens in chronic IBD, favorable experiences, minimal adverse effects, and low cost of the drug, Tylosin remains an option for treatment of canine IBD.

True

This drug is by far the most commonly used lincosamide (protein synthesis inhibitor).

Clindamycin

In small animals clindamycin is used to treat these four conditions.

Wounds Abscesses Periodontal disease Osteomyelitis

Lincosamides are ___ inhibitors.

Protein synthesis

What are the two categories of Antimetabolites (inhibitors of intermediate metabolism)?

PABA analogs Folate reduction inhibitors

Name three PABA analogs (Antimetabolites)

Sulfadimetoxine Sulfadiazine Sulfametoxazole

Name two folate reduction inhibitors (Antimetabolites).

Ormetoprim Trimethoprim

The combination of a sulfonamide with a folate reduction inhibitor is ___.

Synergistic and bacteriocidal

There are numerous mechanisms of resistance to the Antimetabolites; the most important plasmid-mediated form of resistance is ___, which has limited the clinical utility of these drugs in many clinical situations.

Impaired penetration

Are Antimetabolites useful in treating anaerobes?

Potentiated _____ are NOT good choices for Staph, Enterococcus, E. Coli, Proteus, Klebsiella, Psuedomonas, and many anaerobes.

Sulfonamides

Sulfonamides are inhibitors of ____.

Intermediate metabolism

The most important adverse effect of sulfonamides is a ___ which occurs in people too.

Hypersensitivity reaction

If a decrease in tear production is noted, these drugs should be discontinued, with normal tear production expected to resume.

Sulfonamides (Antimetabolites)

_____ can cause immune-mediated diseases ranging from mild to severe and affect skin, liver, kidney, hematopoietic system, and eyes.

Sulfonamides (Antimetabolites)

Sulfonamides can cause ____ - decreased tear production by the lacrimal glands - and it is recommended that the patient be monitored during treatment with ___.

Keratoconjunctivitis sicca (KCS) Schirmer tear tests

Rarely, ____ associated with sulfonamide crystalluria has been reported.

Nephrotoxicity

Sulfonamides are metabolized by ___. Because dogs lack this metabolic pathway, they are less likely to develop nephrotoxicity associated with ____ than other species.

Acetylation Sulfonamide crystalluria

Sulfonamides and potentiated sulfonamides are available in a variety of formulations (oral, injectable, feed additives) with indications including the treatment of which of the below? - intestinal infections - infections in CNS, joints - bacterial enteritis - bacterial pneumonia - skin and soft tissue infections in dogs and cats - cystitis and prostate in dogs

All of the above

Name the four most common sulfonamides used in veterinary medicine.

Sulfadimethoxine Sulfadimethoxine + Ormetoprim Sulfadiazine + trimethoprim Sulfamethoxazole + trimethoprim

_______ have caused the most tissue residue violations in the U.S. with the greatest problems coming from pork, veal, and poultry.

Sulfonamides

This sulfonamide (antimetabolite) is labeled for use in many species.

Sulfadimethoxine

This sulfonamide (antimetabolite) is labeled for use in dogs.

Sulfadimethoxine + Ormetoprim

This sulfonamide (antimetabolite) is labeled for use in horses - availability for dogs and cats has declined.

Sulfadiazine + trimethoprim

This sulfonamide (antimetabolite) is most commonly a human formulation but is used off-label in dogs, cats, and horses.

Sulfamethoxazole + trimethoprim

Nucleic acid synthesis inhibitors include __, ___, and ___.

Fluoroquinolones Rifampin Metronidazole

Name seven Fluoroquinolones

Enrofloxacin Orbifloxacin Difloxacin Marbofloxacin Danofloxacin Ciprofloxacin Pradofloxacin Enro-Orbi-Di-Margo-Dano-Cipro-Prado

What is the MOA of Fluoroquinolones (Nucleic acid inhibitors)?

Inhibit bacterial DNA gyrase (topoisomerase II) and topoisomerase IV enzyme which are necessary for transcription, translation, and bacterial replication.

Are Fluoroquinolones bacteriostatic or bacteriocidal?

Bacteriocidal

Fluoroquinolones inhibit ____.

Nucleic acid synthesis

What is the MOA of rifampin?

Inhibits DNA-dependent RNA polymerase interfering with RNA synthesis Bacteriocidal

Is rifampin bacteriostatic or bacteriocidal?

Bacteriocidal at high concentrations

What is the MOA of metronidazole?

Impairs microbial RNA and DNA synthesis by an undefined mechanism.

Is metronidazole bacteriostatic or bacteriocidal?

Bacteriocidal

Fluoroquinolone (Nucleic acid inhibitor) mechanism of resistance

Alteration of target - decreased porin size by gram negative bacteria results in failure of drug to reach its target

Rifampin (Nucleic acid synthesis inhibitor) mechanism of resistance

Alteration of drug target; if used as a sole agent, resistance often develops rapidly, limiting the usefulness of this drug

Metronidazole (Nucleic acid synthesis inhibitor) mechanism of resistance

Unknown

Fluoroquinolones (Nucleic acid inhibitors) are ineffective against ____.

Anaerobes

___ is a “next generation” fluoroquinolone FDA approved for cats only and has greater gram positive anaerobe activity while maintaining gram negative activity.

Pradofloxacin

Metronidazole is effective against gram positive and gram negative ___.

Anaerobes

Metronidazole is a __ inhibitor.

Nucleic acid synthesis

___ are effective in treating gram positive and gram negative aerobes.

Fluoroquinolones

Rifampin is effective against gram ____ _____.

Gram positive aerobes

Fluoroquinolones (Nucleic acid synthesis inhibitors) can cause irreversible _____.

Cartilage damage in growing animals

____ should not be used in growing animals.

Fluoroquinolones

This Nucleic acid synthesis inhibitor can cause retinopathy in cats resulting in irreversible blindness.

Fluoroquinolones Tends to be related to higher doses, or use in cats with compromised renal function

At high plasma concentrations such as those achieved after IV injection or extremely high oral doses, ___ can be induced by Fluoroquinolones.

Seizures

Rifampin can cause ____ toxicity and a _____.

Liver toxicity Red-orange discoloration of urine

Rifampin ___ drug metabolizing enzymes.

Induces *drug interactions are a concern

Are drug interactions a concern with rifampin?

Yes - it induces drug metabolizing enzymes

Metronidazole can cause dose-dependent ___.

Vestibular toxicity Generally slowly reversible

Metronidazole caused ___ in two cats.

Neurotoxicosis

Three Fluoroquinolones (Nucleic acid synthesis inhibitors) are FDA approved for use in dogs and cats:

Enrofloxacin Marbofloxacin Orbifloxacin

One fluoroquinolone (Nucleic acid synthesis inhibitor) is labeled only for use in dogs:

Difloxacin

One fluoroquinolone (Nucleic acid synthesis inhibitor) is labeled only for use in cats:

Pradofloxacin

_____ have a lower incidence of side effects than aminoglycosides.

Fluoroquinolones

Fluoroquinolones are ___ and achieve high intracellular concentrations and penetrate tissues including prostate, respiratory tract and CNS.

Lipid soluble

All veterinary labeled Fluoroquinolones achieve high concentrations in urine (and are therefore good choices in treating resistant UTIs) except:

Difloxacin

Which Fluoroquinolones (Nucleic acid synthesis inhibitors) are approved for use in horses?

None, but Enrofloxacin, Orbifloxacin, and Marbofloxacin have been used orally and by injection.

In cattle, which two Fluoroquinolones are approved for treating respiratory disease?

Enrofloxacin Danofloxacin

Is ELDU of Fluoroquinolones in food animals legal?

Why are Fluoroquinolones that were once approved for use in poultry pulled from the market in the US?

Because of the potential for causing spread of resistant Campylobacter

Fluoroquinolones are ____ after oral administration, although __ do occur.

Well absorbed Drug interactions

Fluoroquinolones ______ CYP450 drug metabolizing enzymes.

Inhibit Can cause an increase in plasma concentrations of some drugs if administered concurrently

Divalent (magnesium and calcium) and trivalent (aluminum) cations significantly ___________ and can lead to therapeutic failure of Fluoroquinolones.

Decrease oral bioavailability

Pradofloxacin has been shown to cause ____ in dogs, potentially resulting in severe thrombocytopenia and neutropenia.

Bone marrow suppression

Which fluoroquinolone has been shown to cause bone marrow suppression in dogs?

Pradofloxacin

In veterinary medicine, rifampin is used mainly in combination with ___ for treating ____.

Macrolides Rhodococcus equi pneumonia in foals

Are there FDA approved veterinary formulations for metronidazole?

This Nucleic acid synthesis inhibitor is used primarily to treat anaerobic infections in dogs and horses.

Metronidazole

Is it legal to use metronidazole (a Nucleic acid synthesis inhibitor) in food animals?

Is metronidazole (a Nucleic acid synthesis inhibitor) convenient for dosing cats?

Metronidazole is highly _____ therefore distributes well to the CNS and into abscesses.

Lipid soluble

MOA of polymixin B

Decomposes in acidic environments to release formaldehyde; Formaldehyde acts as a urinary antiseptic

This drug has been used for long-term maintenance of refractive UTIs in dogs.

Polymyxin B/Methenamine

_________ is well absorbed after oral administration and is excreted unchanged in the urine. Acidic urine results in the release of formaldehyde.

Methenamine/Polymyxin B

The Polymyxins are water soluble products of ___. They are basic, cyclic decapeptides.

Bacillus Polymyxa

T/F: Polymyxin B also comes in many topical preparations - otic, ocular, ophthalmic.

True

Polymyxin B is used at low, carefully controlled doses to bind ____.

Endotoxin

_____ may develop resistance to polymyxin B through altered permeability.

Pseudomonas

MOA Polymyxin B (endotoxins)

Detergent-like action disrupts gram negative cell membranes Cationic polymyxins interact with an ionic phospholipids (endotoxin) in the gram negative cell wall, disrupting cell wall integrity

________ is an indication for using low, carefully controlled doses of polymyxin b to bind endotoxins.

Equine colic

Oral bioavailability of polymyxins is ___.

Very poor

The polymyxins display ___ in the body, where binding to mammalian cell membranes contributes to significant accumulation during lung therapeutic regiments.

Poor distribution

Elimination of polymyxin B is via:

Glomerular filtration of the parent compound

Parenteral administration of polymyxin may lead to:

Nephrotoxicity Neuromuscular blockade CNS toxicity

Polymyxin toxicities appear to be ____.

Dose dependent Treatment with a polymyxin requires strict adherence to dose guidelines

Drugs to consider with MRSA infection if a susceptibility test can confirm activity.

Chloramphenicol Tetracycline (doxycycline, minocycline) Aminoglycosides (gentamicin, Amikacin) Rifampin

Treatment of Pseudomonas

Amikacin and gentamycin 2nd/3rd generation cephalosporins (ceftazidime, cefotaxime) Anti-pseudomonas penicillins (Ticarcillin, piperacillin, carbenicillin, piperacillin-tazobactam) Imipenem (IV) Fluoroquinolone + a beta-lactam

Tx Nocardia

Potentiated sulfonamides

Tx mycoplasma

Tetracyclines Macrolides Amphenicols

Tx rickettsiaceae and anaplasmataceae

Tetracyclines Amphenicols

Tx Gram positive anaerobes

Pradofloxacin (cat) Metronidazole (no cat) Aminopenicillins Newer macrolides Clindamycin Natural penicillins Tetracyclines

Tx gram negative anaerobes

Pradofloxacin (cat) Metronidazole (no cat) Aminopenicillins Newer macrolides Amphenicols

Tx gram positive and negative anaerobes

Pradofloxacin (cat) Metronidazole (no cat) Aminopenicillins Newer macrolides

Treatment only gram positive anaerobes

Clindamycin Natural penicillins Tetracyclines

Treatment only gram negative anaerobes

Amphenicols

III - Antibacterial Agents Flashcards

(231 cards)