ANTIMICROBIALS

Aminoglycosides	Quinolones
Antifungals	Isoniazid
Antiretrovirals	Penicillins
Carbapenems	Probiotics
Cephalosporins	Sulfonamides
Chloramphenicol	Tetracyclines
Macrolides

Antibiotic induced diarrhea

Duration of diarrhea was significantly shortened (25 vs. 52h) with use of a soy-fiber-enriched formula (Isomil DF, 30% of daily intake) x 10d compared with regular soy formula in a randomized trial of 55 generally healthy children 5-18mos with antibiotic-induced diarrhea and acute otitis media (J. Peds. 139:578, 2001--JW)
In a meta-analysis of 34 randomized trials in pts from 6mos-71y old, probiotics sig. reduced incidence of antibiotic-associated diarrhea, more so in children (Lancet inf. Dis. 6:374, 2006--AFP)

"IQ" = "inhibitory quotient"--ratio between conc. of ABX in pt. body fluid at site of inf. & MIC; should be >10

Newer Antibiotics:

"Synercid" (Quinupristin/Dalfopristin), a "streptogramin" antibiotic, introduced 1999 for Vancomycin-resistant Enterococcus faecium (not effective against E. faecalis); also effective for staph (including MRSA) and strep but not gram-negatives; dose is 7.5mg/kg IV Q8-12h; (causes infusion site inflammation in 75%; best through a central line); can cause severe arthralgias and myalgias; dose may need to be adjusted in hepatic but not in renal failure; may increase levels of nifedipine, midazolam, and cyclosporine (Med. Lett. 41:109, 1999)
Linezolid (Zyvox), an "oxazolidinone" antibiotic, introduced in 2000 for Vancomycin-resistant Enterococcus (both E. faecium and E. faecalis); also effective against staph (including MRSA) and strep but not against gram-negatives; dosing 400-600mg PO Q12h/600mg IV Q12h; a weak inhibitor of MAO so be caresful with co-administration of pseudoephedrine, phenylpropanolamine, SRI's, meperidine, etc. Can cause diarrhea, n/v, thrombocytopenia (monitor platelets if givine > 2wks) (Med. Lett. 42:45, 2000)
Daptomycin (Cubicin), a "cyclic lipopeptide," introduced in 2003; can be used for methicillin-resistant Staphylococcus aureus; can cause elevations in serum CPK levels in some patients and perhaps peripheral neuropathy.
Telavancin, a "lipoglycopeptide"--May be associated with nephrotoxicity and qtC PROLONGATION
Tigecycline (Tygacil), a "Glycylcycline" antibiotic, for IV use; inhibits protein translation in bacteria. Structurally similar to Tetracyclines and may have similar adverse effects
Telithromycin (Ketek), a "ketolide" antibiotic (similar to macrolides but with differences intended to overcome antimicrobial resistance). May be associated with hepatotoxicity per case reports (NEJM 354:329, 2006--JW)
Fidaxomicin (Dificid)
- A "macrocyclic" antibiotic that is narrow in antimicrobial spectrum and minimally absorbed from the gut.
- Not yet approved for use in the U.S. as of 2011
- For Clostridium dificile, at dose of 200mg Q12h, associated with sig. lower 4wk recurrence rates than vancomycin in one randomized study (13% vs. 24%; poster presented @ Interscience Conference on Antimicrobial Agents and Chemotherapy; FP News 10/15/09)