Pefloxacin Rifampicin

Among fluoroquinolones, ofloxacin, pefloxacin and sparfloxacin can be used in alternative regimen, when drugs like rifampicin can not be used. Detailed pharmacology of quinolones is discussed in chapter Sulfonamides, nitrofurans and quinolones. ... 

A study in 8 healthy subjects found that rifampicin 900 mg daily for 10 days decreased the half-life and AUC0.12 of pefloxacin 400 mg twice daily by about 30%, due to a 35% increase in total plasma clearance. Despite these changes the serum pefloxacin levels still remained well above the minimal inhibitory concentrations (0.5 mg/L) for 90% of strains of methicillin-sensitive S. aureus and S. epidermis A single-dose study in 5 healthy subjects found that pefloxacin 500 mg increased the AUC of a single 600-mg dose of rifampicin by about twofold. In a further study the urinary recovery of rifampicin was increased from 15.6% of the dose to 20.1% by pefloxacin. ... 

Orisakwe OE, Akunyili DN, Agbasi PU, EzejioforNA. Some plasma and saliva pharmacokinetic parameters of rifampicin in the presence of pefloxacin. Am J Ther (2004) 11, 283-7. 

Orisakwe OE, Agbasi PU, Ofoefule SI, IlonduNA, Afonne OJ, Anusiem CA, Ilo CE, Madu-ka SO. Effect of pefloxacin on the urinary excretion of rifampicin. Am J Ther (2004) 11,13-16. 

A patient had a marked increase in the effects of acenocoumarol (Quick time reduced from 26% to less than 5%) within 5 days of starting to take pefloxacin 800 mg daily and rifampicin 1.2 g daily Rifampicin is an enzyme inducer, which normally causes a reduction in the effects of the anticoagulants , (p.375), so the findings in this case are surprising. 

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See also in sourсe #XX -- [ ]

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