Quinolines and Sulfonamides Flashcards
Drugs targeting nucleic acids
Quinolones
MOA for quinolones
Inhibits bacterial enzyme DNA gyrase
DNA damage and cell death (bactericidal) in gram + and -
Resistance to quinolones
Due to modification of target DNA gyraze enzyme, mutations at gyrA gene and parC gene
Induction of microbial efflux pumps
PK of quinolones
Chelate with multivalent cations in food
Higher t 1/2 in IV routes
Distributes into all body tissues and fluids
8-10x MIC required
Dog and cats use of quinolones
Prostatitis, mastitis, resp. infection, pyoderma and conjunctivitis
Peritonitis and otitis
Ruminant uses of quinolones
Reps. infection, mastitis, metritis, colibacillosis, conjunctivitis, mycoplasmosis- pneumonia and otitis
Poultry uses of quinolones
Colibacillosis, salmonellosis, fowl cholera
Quinolones drug interactions
Synergistic with B-L aminoglycoside, clindamycin, metronidazole
ELDU in food producing animals prohibited
Toxic effects of quinolones
Cartilaginous erosions in growing animals
Retinal damage (blindness) in cats
Hypersensitivity
↑ risk of seizures
T/F: Fluoroquinolones should not be selected as first choice drugs
TRUE
What can quinolones possibly cause in humans and dogs?
Tendinopathy, tendinitis and tendon rupture
Rifamycins
High activity against gram + (mycobacterium sp.)
Lung infections of horses caused by Rhodococcus epi
Rifampin + clarithromycin treats…
K9 leproid granuloma syndrome
Metronidazole
Antimicrobial and antiprotozoal
Acute gingivitis and periodontal disease in dogs and cats
Sulfonamides antimicrobial activity
Bacteria, chlamydia, toxoplasma and coccidia
Sulfonamides MOA
Sulfonamides inhibits dihydropterate synthetase
Sulfonamides + trimethoprim MOA
Dihydrofolate reductase (DHFR)
Interferes with protein synthesis and bactericidal
Sulfonamides are highly soluble for ….
UTI
Sulfonamides are poorly soluble in…
Gut acting
Bacterial hydrolysis at lower GI release of active sulfathiazole
Sulfasalazine
Converted to sulfapyridine and 5-aminosalicylic acid
Useful in ulcerative colitis in dogs
General properties of Sulfonamides
Weak acids more soluble in alkaline pH
Crystalize in renal tubules at low urine pH with high doses
Adverse effects of Sulfonamides
Crystalluria
Delayed hypersensitivity → hepatic necrosis
Doberman Pinschers more susceptible
Blood clotting disorders
Reversible hypothyroidism
What causes sulfonamide induced KCS (dry eye)?
Sulfasalazine, sulfadiazine, sulfamethoxazole
Sulfonamides resistance
Efflux pumps, change in target enzymes
Chromosomal resistance
Plasmid-mediated sulfonamide resistance**
In what situation are Sulfonamides not responsive?
Chronic infections with large amounts of exudate or tissue debris
Sulfonamides indications
Infections of the GI, respiratory, urinary and CNS
with adequate drinking water
Diaminopyrimidines (potentiated sulfonamides)
Inhibit dihydrofolate reductase in bacteria and protozoa
Combined with Sulfonamides → sequential blockade of microbial enzyme systems
Sulfadiazine + pyremethamine
Treats equine protozoal myeloencephalitis caused by sarcocystis neurona
Sulfomanide residues
More # of residues than any other class
Highest occurrence in pork (veal and poultry)
