Human vitreous distribution of linezolid after a single oral dose.
OBJECTIVE
To evaluate the relationship between vitreous linezolid concentrations versus both time and serum concentrations after a single 600 mg oral dose.


METHODS
Two groups of six subjects undergoing a pars plana vitrectomy indicated by macular pucker or full thickness macular hole were given a single tablet of linezolid before surgery. The early group underwent vitrectomy at random times before the time of maximum serum linezolid concentration (i.e., 77 minutes) and the late group underwent vitrectomy at random times afterward. Each patient had a serum sample drawn shortly before and after vitrectomy and the vitreous specimen was sampled at the initiation of surgery.


RESULTS
The early group and late group had mean vitreous linezolid concentrations of 0.06 mcg/mL and 1.25 mcg/mL, respectively. The vitreous linezolid concentration showed a strong correlation to the interpolated serum concentration (R2 = 0.74, P < 0.01) at the time of vitrectomy.


CONCLUSIONS
The study demonstrates that linezolid penetrates the blood-retina barrier in noninflamed eyes. Because the vitreous concentrations appeared to exponentially trend upward with time and 33% of the late group achieved sufficient MIC90 levels for the common pathogens found in postoperative endophthalmitis, adequate concentrations might be achieved with an altered dosing regimen to achieve higher serum steady state levels. Further study is warranted.
Ciulla
Thomas A
TA
Vitreoretinal Service, Midwest Eye Institute, Indianapolis, Indiana 46280, USA. thomasciulla@yahoo.com
Comer
Grant M
GM
Peloquin
Charles
C
Wheeler
Jackie
J
D000081:Acetamides / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000284:Administration, Oral; D000368:Aged; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001682:Biological Availability; D001813:Blood-Retinal Barrier / Q000187:drug effects; D005260:Female; D006801:Humans; D000069349:Linezolid; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D023303:Oxazolidinones / Q000008:administration & dosage / Q000493:pharmacokinetics*; D012164:Retinal Diseases / Q000601:surgery; D014821:Vitrectomy; D014822:Vitreous Body / Q000378:metabolism* / Q000601:surgery
D000081:Acetamides; D000890:Anti-Infective Agents; D023303:Oxazolidinones; D000069349:Linezolid