AMINOGLYCOSIDES -Used with serious gram negative bacterial infections -suffix –micin or –mycin (exception: Amikacin) NOTE: tetracyclines also use –mycin Amikacin Injection Gentamicin Topical, injectable Neomycin Topical, oral AMINOGLYCOSIDES

-Bactericidal by affecting the ability of bacteria’s ribosomes to assemble proteins -Aminoglycosides must be inside the bacterial cell to produce its effects and oxygen must be present for Aminoglycosides to enter Ineffective against anaerobic bacteria and in areas lacking oxygen (colon, deep puncture wounds) The concurrent use penicillin enhances the ability of Aminoglycosides to enter -Once daily dosing is safest AMINOGLYCOSIDES

AMINOGLYCOSIDES -Absorbed well through skin that is not intact -Pyogenic infections limit the action of Aminoglycosides as the medication will bind to the debris instead of the body’s cells. Clean wound first. NEPHROTOXOCITY and OTOTOXICITY are side effects of normal, high, or frequent doses as Aminoglycosides accumulate in the kidneys and inner ear (this can also be true for fetuses as they easily cross the placenta) Nephrotoxicity may be reversible if the drug is reduced /withdrawn before there is necrosis in the tubules Accumulation in the inner ear can cause deafness Ototoxicity can also affect balance AMINOGLYCOSIDES

FLUOROQUINOLONES (QUINOLONES) -Most have –floxacin as a suffix Ciprofloxacin (Cipro) Oral and injectable Used in small and large animals Enrofloxacin (Baytril) Oral, Injectable, and topical Marbofloxacin (Zeniquin) Oral Used in small animals Orbifloxacin (Orbax) FLUOROQUINOLONES (QUINOLONES)

QUINOLONE MECHANISM OF ACTION -Interfere with bacterial DNA which must be tightly coiled. Quinolone attack the bacteria's enzyme gyrase whose role is to supercoil -Bactericidal -Effective against common gram negative and positive bacteria (except Strep) -Used for skin, urinary, prostatic, and respiratory infections -Absorbed better when administered orally in small animals and by injection in large animals QUINOLONE MECHANISM OF ACTION

-Can cause bubblelike lesions in rapidly growing cartilage -Can cause bubblelike lesions in rapidly growing cartilage. Degenerate and arthritic changes can arise as adults contraindicated In growing animals -High doses in cats can cause changes in the retina, leading to blindness -Reserve for serious infections as bacterial resistance is a problem -Fluoroquinolones cannot be used extra-label on food animals FLUOROQUINOLONES

TETRACYCLINES -Used in large and small animals -Used to TX: RMSF, ehrlichiosis, salmon poisoning, hemobartonellosis, mycoplasma pneumonia, Chlamydia, psittacosis, Lyme disease -cycline suffix -Older tetracyclines: tetracycline and oxytetracycline, newer tetracyclines: doxycycline, minocycline TETRACYCLINES

TETRACYCLINES -Bacteriostatic -Bind to bacterial ribosomes and prevent RNA from attaching. This stops protein synthesis. Inhibit cellular function and division. Rely on the body having a functional immune system since they are Bacteriostatic TETRACYCLINES

TETRACYCLINE PRECAUTIONS Chelators of calcium which can effect developing teeth and bones If given to young, growing animals both can be effected Dentin and enamel formation can be disrupted and a yellow discoloration may develop Bone development can be slowed if calcium is chelated GI upset may be seen with oral administration Normal flora in rumen can be killed off causing rumen inactivity Irritation of GI mucosa in dogs causing V/D, anorexia Cats are susceptible to esophageal stricture- chase with at least 6 mL water TETRACYCLINE PRECAUTIONS

TETRACYCLINE PRECAUTIONS DO NOT GIVE IV TO HORSES Arrythmias, collapse, and death Give slowly IV to other species Expired tetracycline and oxytetracycline can form a nephrotoxic compound that damages the PCT. Causes FANCONI’S SYNDROME- glucose reabsorption is impaired. Glucosuria without hyperglycemia TETRACYCLINE PRECAUTIONS

SULFONAMIDES & POTENTIATED SULFAS AKA Sulfa drugs Resistance is seen because of overuse Often potentiated to increase efficacy and make them bactericidal (otherwise Bacteriostatic) Trimethoprim and ormetoprim Commonly used sulfa drugs: Sulfadimethoxine (Albon, combined with ormetoprim in Primor) Sulfadiazine (combined with trimethoprim in Tribrissen) Sulfasalazine (GI) SULFONAMIDES & POTENTIATED SULFAS

BACTERIOSTATIC: organisms that make their own folic acid needed for protein and nucleic acid metabolism. Sulfonamides block an enzyme needed for this process. Potentiators block different enzymes, but still those that are required for folic acid. When combined, the compound is BACTERICIDAL. Broad spectrum: many G+ and G- bacteria, coccidian, and Toxopasma Often used for UTIs. SULFONAMIDES

Sulfonamides are known to produce keratoconjunctivitis sicca in dogs Sulfonamides are known to produce keratoconjunctivitis sicca in dogs. It is often not reversible. Skin reactions may be seen. Thrombocytopenia and Leukopenia in small animals can occur. Crystalluria can occur which can damage renal tubules and lead to renal failure. Carnivores are more likely than herbivores. Likeliness increases if dehydrated Oral sulfa can cause salivation in cats if tablet breaks in mouth. SULFONAMIDES

LINCOSAMIDES Clindamycin (Antirobe), lincomycin (Lincosin) Bacteriostatic or bactericidal by affecting protein synthesis. Action depends on concentration at infection site. Gram +, anaerobes, and Toxoplasma Contraindicated to use in horses, ruminants, hamsters, guinea pigs, rabbits. Can cause serious GI issues and death. Clindamycin is often used for dental infections, deep pyodermas, accesses, bite wounds, osteomyelitis LINCOSAMIDES

Erythromycin, azithromycin (Zithromax), tilmicosin (Micotil), tylosin (Tylan) Tylosin and tilmicosin are primarily used in cattle. Bacteriostatic by inhibiting protein synthesis Stimulates intestinal motility so cramping is common Erythromycin can cause fatal diarrhea in horses MACROLIDES

METRONIDAZOLE AKA Flagyl Bactericidal, possibly by effecting DNA synthesis Effective against protozoa, including Giardia and Trichomonas. Good for treating infections in bowel or deep wounds. Neurological side effects can be seen with high doses or prolonged treatment. METRONIDAZOLE

Low concentrations are bacteriostatic, high are bactericidal Disrupts protein synthesis Cannot be used in food animals Can cause aplastic anemia in humans Avoid inhaling powder, wash hands, wear gloves CHLORAMPHENICOL

GRISEOFULVIN: oral med used to treat dermatophytes (ringworm) Known for being teratogenic in cats. Do not use in pregnant animals. Use caution when handling if pregnant. AMPHOTERICIN B: IV med for deep or systemic infections Rapid onset of action Nephrotoxicity is extremely common and dose related. Monitor BUN and creatinine every time. ANTIFUNGALS

AZOLES: oral (ketoconazole, itraconazole, and fluconazole) or topical (miconazole, clotrimazole) meds for deep or systemic infections Usually used before Amphotericin B because side effects are fewer Topical meds are used for dermatophytosis, topical yeast infections GI side effects are common with oral meds Hepatotoxicity is an issue with ketoconazole ANTIFUNGALS