Miscellaneous Antibiotics

Question 1

What are the most commonly prescribed fluoroquinolones?

Answer 1

cipro, levofloxacin (Levaqin), moxifloxacin (avelox)

Question 2

Describe how fluoroquinolones work

Answer 2

Good tissue distribution and distribution into fluids except CNS. All undergo renal elimination except moxifloxacin. Half lives from 4-12 hours. Inhibit DNA gyrase and topoisomerase IV necessary for replication of bacteria

Question 3

What are the spectrums of activity for fluorquinolones?

Answer 3

aerobic gram (-): all fluoroquinolones. pseudomonas: cipro, levo. gram (+): levo, moxi, gem. anaerobic: moxi

Question 4

What kind of diseases can be treated with fluoroquinolones?

Answer 4

UTI, pneumonia, STIs, skin and soft tissue, GI, traveler’s diarrhea, osteomyelitis

Question 5

How should fluoroquinolones be used to treat HAP?

Answer 5

Use ciprofloxacin or levofloxacin in addition to other agents for their Pseudomonas coverage

Question 6

What is the black box warning associated with fluoroquinolones?

Answer 6

increased risk of tendinitis and tendon rupture that’s further increased in patients >60 years, in patients taking corticosteroid drugs, and in patients with kidney, heart or lung transplants

Question 7

What are the drug interactions of fluoroquinolones?

Answer 7

Cipro is an inhibitor of CYP4501A2: Theophylline, warfarin, tizanidine, propranolol. Antacids, sucralfate, magnesium, calcium, iron all decrease the absorption of FQs

Question 8

What are some other features of fluoroquinolones that should be taken into consideration before prescribing?

Answer 8

caution when pt in renal failure, has hepatic dsyfxn, or history of arrhythmias w/QT prolongation. Contains the only oral agents against Pseudomonas

Question 9

What drugs are sulfonamides?

Answer 9

Sulfamethoxazole/Trimethoprim (SMX-TMP) (Bactrim DS, Septra)

Question 10

Describe how sulfonamides work?

Answer 10

distribution to body tissue, CSF, pleural fluid, synovial fluid. Eliminated thru liver and kidneys. They’re folic acid synthesis inhibitors.

Question 11

What diseases can be treated with sulfonamides?

Answer 11

UTIs, PCP or P. jiroveci pneumonia, Toxoplasmosis, MRSA. Not recommened for sinusitis or otitis media due to resistance

Question 12

What are the most common SE of sulfonamides?

Answer 12

rash (can lead to Stevens-Johnson syndrome), fever, and GI sx

Question 13

What are drug interactions of sulfonamides?

Answer 13

Potentiates the effects of: Warfarin, Phenytoin, Hypoglycemic agents, Methotrexate

Question 14

What are some other features of sulfonamides that should be considered before prescribing?

Answer 14

For oral use only. Most commonly used for UTIs. Pregnancy category C. Good for MRSA infections. Don’t use with a sulfa allergy

Question 15

Describe the use of nitrofurantion (Macrobid)

Answer 15

Only for treatment and prevention of uncomplicated urinary tract infections and who have sulfa allergy. PO

Question 16

How is nitrofurantion distributed?

Answer 16

rapidly absorbed and only in serum for 30 min.
Inadequate drug levels in the bladder if the creatinine clearance is abnormal (GFR < 60 mL/min). Contraindicated in patients with a creatinine clearance < 60 mL/min

Question 17

What are the SE associated with nitrofurantion?

Answer 17

most commonly nausea and vomiting. pulmonary rxns, hepatic effects, peripheral neuropathy in long term use of patients w/renal failure

Question 18

What is the anti-anaerobic antibiotic?

Answer 18

metronidazole (Flagyl)

Question 19

How is metronidazole absorbed?

Answer 19

Metabolized by the liver. Absorbed well PO. Good tissue penetration in most locations. Half life 6-9 hours

Question 20

How does metronidazole work?

Answer 20

Causes DNA strand breakage therefore inhibiting bacterial protein synthesis

Question 21

What is the spectrum of activity for metronidazole?

Answer 21

gram positive and negative anaerobes, H. pylori, Trichomonas vaginalis

Question 22

What infections is metronidazole the treatment of choice?

Answer 22

Bacterial vaginosis, Trichomoniasis, C. difficile diarrhea

Question 23

What is the black box warning for metronidazole?

Answer 23

shown to be carcinogenic in mice and rats. Unnecessary use of the drug should be avoided.

Question 24

What are the SE of metronidazole?

Answer 24

Commonly N/V, abdominal pain, metallic taste. Seizures at high doses. Peripheral neuropathy for prolonged courses. pancreatitis

Question 25

What are drug interactions of metronidazole?

Answer 25

Enhances anticoagulant effect of warfarin. Alcohol: Flushing, palpitations, nausea, vomiting. Phenobarbital, phenytoin, rifampin increase the metabolism of Flagyl which may lead to treatment failure