Quinolines and Sulfonamides

Question 1

Drugs targeting nucleic acids

Answer 1

Quinolones

Question 2

MOA for quinolones

Answer 2

Inhibits bacterial enzyme DNA gyrase
DNA damage and cell death (bactericidal) in gram + and -

Question 3

Resistance to quinolones

Answer 3

Due to modification of target DNA gyraze enzyme, mutations at gyrA gene and parC gene
Induction of microbial efflux pumps

Question 4

PK of quinolones

Answer 4

Chelate with multivalent cations in food
Higher t 1/2 in IV routes
Distributes into all body tissues and fluids
8-10x MIC required

Question 5

Dog and cats use of quinolones

Answer 5

Prostatitis, mastitis, resp. infection, pyoderma and conjunctivitis
Peritonitis and otitis

Question 6

Ruminant uses of quinolones

Answer 6

Reps. infection, mastitis, metritis, colibacillosis, conjunctivitis, mycoplasmosis- pneumonia and otitis

Question 7

Poultry uses of quinolones

Answer 7

Colibacillosis, salmonellosis, fowl cholera

Question 8

Quinolones drug interactions

Answer 8

Synergistic with B-L aminoglycoside, clindamycin, metronidazole
ELDU in food producing animals prohibited

Question 9

Toxic effects of quinolones

Answer 9

Cartilaginous erosions in growing animals
Retinal damage (blindness) in cats
Hypersensitivity
↑ risk of seizures

Question 10

T/F: Fluoroquinolones should not be selected as first choice drugs

Answer 10

TRUE

Question 11

What can quinolones possibly cause in humans and dogs?

Answer 11

Tendinopathy, tendinitis and tendon rupture

Question 12

Rifamycins

Answer 12

High activity against gram + (mycobacterium sp.)
Lung infections of horses caused by Rhodococcus epi

Question 13

Rifampin + clarithromycin treats…

Answer 13

K9 leproid granuloma syndrome

Question 14

Metronidazole

Answer 14

Antimicrobial and antiprotozoal
Acute gingivitis and periodontal disease in dogs and cats

Question 15

Sulfonamides antimicrobial activity

Answer 15

Bacteria, chlamydia, toxoplasma and coccidia

Question 16

Sulfonamides MOA

Answer 16

Sulfonamides inhibits dihydropterate synthetase

Question 17

Sulfonamides + trimethoprim MOA

Answer 17

Dihydrofolate reductase (DHFR)
Interferes with protein synthesis and bactericidal

Question 18

Sulfonamides are highly soluble for ….

Answer 18

UTI

Question 19

Sulfonamides are poorly soluble in…

Answer 19

Gut acting
Bacterial hydrolysis at lower GI release of active sulfathiazole

Question 20

Sulfasalazine

Answer 20

Converted to sulfapyridine and 5-aminosalicylic acid
Useful in ulcerative colitis in dogs

Question 21

General properties of Sulfonamides

Answer 21

Weak acids more soluble in alkaline pH
Crystalize in renal tubules at low urine pH with high doses

Question 22

Adverse effects of Sulfonamides

Answer 22

Crystalluria
Delayed hypersensitivity → hepatic necrosis
Doberman Pinschers more susceptible
Blood clotting disorders
Reversible hypothyroidism

Question 23

What causes sulfonamide induced KCS (dry eye)?

Answer 23

Sulfasalazine, sulfadiazine, sulfamethoxazole

Question 24

Sulfonamides resistance

Answer 24

Efflux pumps, change in target enzymes
Chromosomal resistance
Plasmid-mediated sulfonamide resistance**

Question 25

In what situation are Sulfonamides not responsive?

Answer 25

Chronic infections with large amounts of exudate or tissue debris

Question 26

Sulfonamides indications

Answer 26

Infections of the GI, respiratory, urinary and CNS
with adequate drinking water

Question 27

Diaminopyrimidines (potentiated sulfonamides)

Answer 27

Inhibit dihydrofolate reductase in bacteria and protozoa
Combined with Sulfonamides → sequential blockade of microbial enzyme systems

Question 28

Sulfadiazine + pyremethamine

Answer 28

Treats equine protozoal myeloencephalitis caused by sarcocystis neurona

Question 29

Sulfomanide residues

Answer 29

More # of residues than any other class
Highest occurrence in pork (veal and poultry)