Nitrofurantoin, Daptomycin, Polymyxin B, Rifaximin

Question 1

Nitrofurantoin - Pharmacologic class

Answer 1

Nitrofuran drug

Question 2

Nitrofurantoin - MoA

Answer 2

Inhibition of bacterial enzymes

Question 3

Nitrofurantoin - Clinical use

Answer 3

Lower UTIs leading to cystitis (inflammation of the bladder)

Acute lower UTIs by E.coli, E. faecalis, K. pneumoniae, Staphylococcus saprophyticus

Acute cystitis (when resistance to trimethoprim-sulfamethoxazole exceeds 20% in local community)

Question 4

Nitrofurantoin - Special considerations

Answer 4

Antimicrobial activity restricted to urinary bladder

Macrocrystalline given with drug to reduce side effects

Given with food to increase absorption and reduce the risk of GI irritation

Question 5

Nitrofurantoin - Adverse effects

Answer 5

GI irritation, nausea, vomiting, diarrhea
Pulmonary fibrosis
Hepatitis
Hematologic toxicity

Question 6

Daptomycin - Pharmacologic class

Answer 6

Lipopeptide

Question 7

Daptomycin - MoA

Answer 7

Inserts lipophilic tail in bacterial cell membrane, causing depolarization and K efflux. Produces arrest in nuclei acid and protein synthesis.

Bactericidal (gram positive)

Question 8

Daptomycin - Clinical use

Answer 8

Strains of MRSA

Vancomycin intermediate and resistant S. aureus

Some strains of Vancomycin resistant enterococci

MRSA skin and skin-structure infections, complication of surgery, diabetic foot ulcers and burns

MRSA bacteremia

Right-sided infective endocarditis (S. aureus)

Question 9

Daptomycin - Special considerations

Answer 9

Daptomycin binds to lung surfactant and should NOT be used for treating pneumonia

Question 10

Daptomycin - Adverse effects

Answer 10

Muscle toxicity (diminished when given intravenously once a day)

Question 11

Polymyxin B - Pharmacologic class

Answer 11

Polypeptide

Question 12

Polymyxin B - MoA

Answer 12

Interacts with the phospholipid component of bacterial cell membranes to discrupt cell membrane integrity and permit cytoplasmic components to leak out of the cell.

Question 13

Polymyxin B - Clinical use

Answer 13

Skin and ocular infections

Gram-negative bacilli (including P. aeruginosa, but not Proteus species)

Question 14

Polymyxin B - Special consideration

Answer 14

Topical administration

Question 15

Polymyxin B - Adverse effects

Answer 15

Nephrotoxicity and Neurotoxicity when given parentally

Question 16

Rifaximin - Pharmacologic class

Answer 16

Rifamycin derivative

Question 17

Rifaximin - MoA

Answer 17

Inhibition of DNA-dependent RNA polymerase

Question 18

Rifaximin - Clinical use

Answer 18

Travellers diarrhea > 12 years
(E.coli)

Hepatic encephalopathy (decrease colonic bacteria that converts foodstuffs to ammonia and other waste products

Relieve symptoms of irritable bowel disease (IBS)

Clostridium difficle colitis

Question 19

Rifaximin - Special considerations

Answer 19

Not effective in patients with fever or blood in the stool, or in persons infected with campylobacter jejuni

Induces cyp—> reduces levels of warfarin, theophylline, steroid, opioids etc.

Question 20

Rifaximin - Adverse effects

Answer 20

Nausea 
Vomiting 
Abdominal distention
Stomach pain
Headache
Dizziness

Question 21

Fidaxomicin - Pharmacologic class

Answer 21

Macrolide

Question 22

Fidaxomicin - MoA

Answer 22

Inhibits RNA polymerases and RNA synthesis in susceptible bacteria

Question 23

Fidaxomicin - Clinical use

Answer 23

Diarrhea caused by Clostridium difficle

Question 24

Fidaxomicin - Special considerations

Answer 24

Prevent recurrences after treatment