Probenecid Cefazolin

The posterior route involves transport across the lipophilic retina and the RPE. Posterior elimination appears to occur via passive diffusion for lipophilic compounds although active transport mechanisms also exist for some endogenous compounds and also for some drugs. Forbes and Becker studied the vitreous elimination of radio-labeled iodopyracet in rabbits and found that while 300 pg labeled with 1 pCi was cleared rapidly with a half-life of three hours, 1.4 mg (also labeled with 1 pCi) was eliminated with an apparent half-life of 17 hours. This increase in half-life, they speculated, was due to saturation of an active transport mechanism (78). Weiner et al. (79) showed that systemic administration of probenecid, which acts by competitive inhibition of weak organic acid transport, increased the intravitreal half-life of iodopyracet to 17 hours. Similar findings were reported by Barza et al. (80,81) who demonstrated that systemic administration of probenecid increased the half-life of intravitreally injected carbenicillin and cefazolin in rabbits and monkeys. 

Duncan WC. Treatment of gonorrhea with cefazolin plus probenecid. J Infect Dis (1974) 130, 398-401. 

Brown G, Zemcov SJV, Clarke AM. Effect of probenecid on cefazolin serum concentraticMis. J Antimicrob Chemother (1993) 31,1009-1011. 

Spina SP, Dillon EC. Effect of chronic probenecid therapy on cefazolin serum concentrations. Ann Pharmacother (2003) 37,621-4. 

SLC22A6 OATl Kidney, brain AcyclovE, adefovE, methotrexate, zidovudine Probenecid, cefadroxil, cefamandole, cefazolin ... 

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