What is the antibiotic spectrum of sulfonamides?
-Broad spectrum -some G+ and - aerobes, not very effective for anaerobes
Which drugs are made inactivated in the presence of purulent material?
Sulfonamides (not effective against anaerobes)
Which drug can stop the reproduction of some protozoa such as coccidia if given early in the disease?
How are Sulfonamides metabolized and excreted?
-relatively insoluble in water -excreted in the urine by filtration and active transport (to get to urine)
T or F Sulfonamides and their metabolites habe high water solubility
F they have low water solubility
What are some adverse effects of sulfonamides (3)?
1. Crytalluria in the kidneys causing renal tubular damage (low water solubility) 2. Irreversible Keratoconjunctivitis Sicca in dogs 3. Salivation and gastric ulceration in cats
Why is it a good idea to rehydrate dehydrated patients first before treating them with sulfonamides?
Because it prevents the formation of crystals in the kidney due to sulfonamides low water solubility
What is Irreversible KCS? What is it a side effect of?
-Irreversible Keratoconjunctivitis Sicca -Irreversible dry eye, caused by inability to produce tears -a side effect of sulfonamides in dogs
______ sulfonamides alone are not used commonly anymore because of ____ ______
-parenteral -acquired resistance
WHat are the potentiated sulfonamides (_____ and _______) used for in small and large animals? What are their routes of administration?
-Sulfa and Trimethoprim -Broad spectrum coverage including chlamydia, and some protozoa (UTIs, respiratory, GIT and wound infections) -oral or injectable
________ (sulfonamide) used in dogs for IBD, UTIs, respiratory, GIT disease and coccidia
What is the mechanism of action of Aminoglycosides?
-Bactericidal -Inhibits protein synthesis by binding to ribosomes
How are aminoglycosides metabolized and excreted?
-poor absorption from GIT so not given orally (except for neomycin in scours) -Not active in acid environments (bases) like necrotic or purulent tissue. -Tends to accumulate in renal tissue which can cause toxicity problems
Aminoglycosides tend to be _____ given not _____ administered. Why? Whats the exception?
-parenterally -orally -not absorbed well from the GIT -The exception is Neomycin which is given orally for scours
Aminoglycosides are (acidic/basic) drugs and so are not active in (acidic/basic) environments such as ____ or ____ tissues
-are bases -not active in acidic environments -necrotic or purulent tissues
What is the major side effect of Aminoglycosides? When is this a problem (4)?
-nephrotoxicity (notorious for causing kidney tissues) -with 1. high doses 2. prolonged treament 3. pre-existing kidney damage 4. dehydration
WHat is a notable adverse effect of aminoglycosides? WHat are the symptoms? Which species is most sensitive?
-Ototoxicity caused by damage to cranial nerve VIII - loss of hearing or loss of balance -cats are most sensitive
Why shouldn't Aminoglycosides be given to a patient with kidney issues or dehydration?
-It's major adverse effect is nephrotoxicity which can be more a problem in patients with kidney disease or dehydration
Which drug is mainly used ______ for tough gram - infections (like what?)
-parenterally -Aminoglycosides (salmonella, proteus, pseudomonas)
Aminoglycosides are used in small, large and exotic patients for such infections as (5):
1. Uterine Infections 2. Septicemia 3. Soft Tissue Wounds 4. Scours 5. Pneumonia
______ of the _____ class is commonly used in equine joints (intra articular injections) for infections or post joint surgery
What is the mechanism of action of Macrolides?
-bacteriostatic -bind to bacterial ribosomes to prevent protein synthesis
What is the antibiotic spectrum of macrolides?
-variable spectrums (e.g. Erythromycin: G+ and a few G-'s, mycoplasma, chlamydia, rickettsia)
How are macrolides metabolized?
-Extremely lipid soluble so easily absorbed and distributed in all body tissues except CNS -Good oral absorption, but can be irritating (erythromycin and tylocin)
The drug _____ of the ______ class can be fatal if accidentally injected into humans, ___, ____, and ____
-Tilmicosin -Macrolide -horses, dogs and pigs
What are some adverse effects of the oral macrolides?
-GIT effects: rectal edema, partial anal prolapses and diarrhea
Name four macrolides and some of their uses:
1. Erythromycin: R.D. in cattle,pigs and sheep; Rhodococcus in foals; Mastitis 2. Tylocin: RD in dogs, cats, cattle, pigs and poultry and swine dysentry 3. Tilmicosin: (long acting SQ injection) pneumonia in cattle, footrot 4. Tulathromycin: RD in cattle
What macrolide is a long term SQ injection used in bovine pneumonia and footrot and has a serious human side effect
Which macrolide can be administered orally, parenterally, intramammarily, opthalmically?
What is the mechanism of action of the fluoroquinolones?
-bactericidal -inhibits bacterial DNA synthesis
What is the antibiotic spectrum of the Fluoroquinolones?
Broad spectrum (considered better against G-) -poor against anaerobes -some activity against mycoplasma and rickettsia
How are fluoroquinolones metabolized?
-rapid oral absorption -highly lipid soluble and low protein binding -Long half life so decreased frequency of dosing -Al, Mg antacids decreas their absorption
Which drug may interfere with normal cartilage maturation in young puppies? What class is it in? WHen can they be used safely?
-Enrofloxacin of the Fluoroquinolones -after the growth plate has closed (not a problem in kittens)
Which Fluoroquinolones has had its dosage decreased in cats because of the occurrence of eye lesions?
T or F Fluoroquinolone are go to first choice drugs
F they are powerful drugs and should be saved till needed
What are some uses of the fluoroquinolone class? (3)
-Skin Infections, UTIs and soft tissue infections
What are polypeptide antibiotics? How are they used (2)?
-Two drugs (Polymixin B and Bacitracin) that some from bacteria -Only used topically or intramammarily
______ are toxic if given orally or injected because of what?
-Polypeptide antibiotics -Not tolerated systemically
What are the three ways polypeptide antibiotics can be administered? The two ways they cant?
Can: 1. Topical 2. Opthalmic 3. Intramammary Can't: 1. Orally 2. Injected
Give examples of topical polypeptide antibiotics
-Polysporin (made from Polymyxin B mixed with Bacitracin) -Bacitracin
Give an example of a polypeptide antibiotic that can be given intramammarily
Polymixin B (plus other antibiotics and a steroid)
What is the mechanism of action of polypeptide antibiotics?
-Bactericidal -Affects permeability of bacterial cell wall allowing cytoplasm to leak out
WHat is the antibiotic spectrum of polypeptide antibiotics? Which is what?
Narrow spectrum (very) -each is effective against one of the gram categories: Polymixin B (G-) and Bacitracin (G+)
How are polypeptide antibiotics metabolized and excreted?
They never are because they can't be given systemically-toxic
What are some adverse effects of polypeptide antibiotics?
Can cause serious neurological and renal damage if given parenterally
What antibacterial are not allowed to be used in food producing animals? (3)
1. Chloramphenicol .2 Nitrofurans 3. Nitroimidazoles
What is the mechanism of action of nitrofurans?
-Bactericidal -Inhibit carbohydrate metabolism of bacteria
What is the antibiotic spectrum of Nitrofurans? Which specific drug has specific organisms it's effective against?
-Broad Spectrum -Furazolidone gets Giardia, Trichomonas, Coccidian protozoa and some fungi
What are some adverse effects of Nitrofurans? (2)
-Suspected human carcinogens so their use in food producing animals is prohibited -May see some GIT upset after oral admin
What is the Nitrofuran drug commonly used for superficil skin infections? When must it be used carefully?
Nitrofurazone -May increase growth of proudflesh in lower linb equine wounds so must be used carefully
Which Nitrofuran is licensed for horses, dogs and cats for ___ ___ ___ and ____
-Nitrofurantoin -URI and UTIs
What is the mechanism of action of Nitroimidazoles?
-Bactericidal -Specific action not known (disrupts DNA synthesis)
What is the antibiotic spectrum of Nitroimidazoles?
Primarily against anaerobes -also against Entamoeba histolytica, Trichomonas, Giardia and Balantidium coli
How are Nitroimidazoles metabolized?
-Lipophilic so rapidly absorbed and distributed after oral admin -distributed to most body tissues including bone, abscesses, the CNS and seminal fluids (less than 20% protein bound) -Metabolized mainly in the liver
How are Nitroimidazoles excreted?
Both the metabolites and the unchanged drug are eliminated in the urine and feces (good for diarrhea)
What is an adverse effect of Nitroimidazoles? Symptoms?
-With chronic mod-high dose therapy can cause neurologic toxicity -Symptoms: nystagmus, ataxia, head-tilt, proprioception issues (is potentially reversible)
What are some uses of Nitroimidazole? (2)
-Often used in large bowel diarrhea and giardia infections (has some inhibitive actions on cell-mediated immunity)
Which drugs are easily absorbed into the CNS? (3)
1. Nitroimidazoles 2.Chloramphenicol and Florphenicol
_____ can be mixed with ____ to make them bactericidal. These are the most _____ ________ sulfas
-Sulfas -Trimethoprim (any potentiated sulfas are bactericidal) -commonly used
_____ are used as antibiotics, against protozoans (giardia) and to calm down diarrhea