War of the Worlds (Antibiotics)

Question 1

What pregnancy category is Bactrim?

Answer 1

C or D. ….I dunno… epocrates says D, but Sanford’s says C….

Question 2

What does it mean for a drug to be ‘bacteriostatic’?

Answer 2

A bacteriostatic agent or bacteriostat, abbreviated Bstatic, is a biological or chemical agent that stops bacteria from reproducing, while not necessarily harming them otherwise. Depending on their application, bacteriostatic antibiotics, disinfectants, antiseptics and preservatives can be distinguished. Upon removal of the bacteriostat, the bacteria usually start to grow again. This is in contrast to bactericides, which kill bacteria.

Question 3

With which antibiotics would you consider telling pts to discontinue alcohol use- for at least the time while on antibiotic therapy?

Answer 3

Flagyl, Bactrim, Tindamax, Isoniazid.

Question 4

A pt. with chronic A-fib who is anticoagulated with coumadin now has a UTI. Susceptibility to the offending agent calls for TMP/SMX as the best choice to treat. Although it is by no means your first choice- you reluctantly proceed with the therapy. What should you monitor closely, and why?

Answer 4

PT/INR. Giving TMP/SMX to a pt on warfarin is potentially dangerous. The drug interaction increases warfarin levels, resulting in a higher risk of bleeding.

Question 5

What kind of coverage can you expect from Bactrim? (i.e., which infections are typically susceptible to TMP/SMX)

Answer 5

TMP-Smx: Tree: (Respiratory tree) otitis media, sinusitis, bronchitis, pneumonia - that are a result of S pne or H flu. M- Mouth: Diarrhea from agents such as Shigella, Salmonella, and E.coli. P - Pee - UTIs, prostatitis, urethritis caused by enterics S - Syndrome (AIDS). Covers Pneumocystis carinii pneumonia (PCP). It is given to PREVENT PCP when CD4 counts drop below 200-250.

Other infections covered by Bactrim: Toxoplasma, Isospora.
Bactrim has NO anaerobic coverage!

Question 6

Pregnancy category for Vancomycin?

Answer 6

C

Question 7

Vancomycin: Oral Absorption %?

Answer 7

0 %

Question 8

A pt. of yours takes Lisinipril, and has just started a course of Bactrim. What should you monitor and why?

Answer 8

Potassium. Bactrim and ACE inhibitor combinations can act to increase K+ levels.

Question 9

A pt. of yours is on Phenytoin, and has now started a course of Bactrim. What should you monitor and why?

Answer 9

Phenytoin levels. Bactrim can act to increase Phenytoin levels.

Question 10

Ceftriaxone seems to be a good ‘go-to’ drug for many infections. But it is not a magic bullet. Name some infections for which Rocephin is NOT a good idea…

Answer 10

MRSA, Listeria, Enterococcus, B. fragilis, Pseudomonas aeruginosa
Is it just me, or are there some major players in this group?

Question 11

Rocephin: Pregnancy Category

Answer 11

B

Question 12

How much (what %) of Ceftriaxone is absorbed orally?

Answer 12

Trick question. Ceftriaxone is IV only.

Question 13

What is a ‘typical’ dose of Ceftriaxone?

Answer 13

1-2 gm IV q24h

Question 14

Does Rocephin achieve therapeutic levels in CSF?

Answer 14

Yes

Question 15

What black box warning is associated with Clindamycin?

Answer 15

C. difficile associated diarrhea

Question 16

Where is Clindamycin metabolized?

Answer 16

Liver. CYP450

Question 17

What (2) Black Box warnings are associated with Ciprofloxaxin?

Answer 17

Tendinitis/Tendon Rupture: Fluoroquinolones assoc. w/ incr. tendinitis/tendon rupture risk in all ages; risk further incr in pts >60 y.o., pts on corticosteroids, and pts w/ kidney/heart/lung transplant

Avoid in myasthenia gravis: fluoroquinolones may exacerbate muscle weakness in pts w/ m.g.

Question 18

Pregnancy category for Ciprofloxacin?

Answer 18

C

Question 19

What is the determination on Ciprofloxacin in a mother who is nursing?

Answer 19

Probably safe: Limited info in animals and/or humans demonstrates no/minimal risk of adverse effects to infant/breast milk production; caution advised

Question 20

A pt. is admitted with Strep pneumo meningitis, and has a severe allergy to penicillin. Name a drug that can be considered

Answer 20

Chloramphenicol

Question 21

Which antibiotic is associated with “Grey baby syndrome”?

Answer 21

Chloramphenicol

Question 22

What is the half life of Azithromycin?

Answer 22

68 hours

Question 23

What antibiotics should be avoided in pts with myasthenia gravis?

Answer 23

Fluoroquinolones, aminoglycosides, polymixins, macrolides (erythromycin, telithromycin)

Question 24

Vancomycin, normally bactericidal, is only bacteriostatic against which group of organisms?

Answer 24

Enterococcus

Question 25

How many classes of penicillins are there? Name them

Answer 25

4; Natural penicillins; Penicillinase-resistant penicillins; Aminopenicillins; Expanded spectrum/ Antipseudomonal penicillins

Question 26

Which are the ‘Natural Penicillins?’

Answer 26

PCN G; PCN V

Question 27

Which are the Penicillinase-resistant penicillins?

Answer 27

Oxacillin, Nafcillin, Methicillin

Question 28

Which are the Aminopenicillins?

Answer 28

Ampicillin, Amoxacillin

Question 29

Which are the Extended Spectrum penicillins?

Answer 29

Ticarcillin, Piperacillin

Question 30

What are the target enzymes of the penicillins?

Answer 30

penicillin binding proteins (PBPs)

Question 31

Name2 ORAL antibiotics that may be considered against Pseudomonas aeruginosa

Answer 31

Ciprofloxacin and Levofloxacin