Intravitreal penetration of oral pefloxacin in humans

Intravitreal pefloxacin therapy in postoperative endophthalmitis

PURPOSE

To study the efficacy of intravitreal pefloxacin in the management of suspected bacterial endophthalmitis.

METHODS

Twenty eyes with suspected postoperative bacterial endophthalmitis were given an intravitreal injection of pefloxacin (200 microg in 0.1 mL). If required the injection was repeated after 24 h. The main parameters evaluated were visual acuity, response to intravitreal therapy and any complications due to intravitreal pefloxacin.

RESULTS

Fourteen eyes (70%) responded to intravitreal pefloxacin therapy alone, while an additional pars plana vitrectomy was required in six eyes (30%). Nineteen eyes retained a visual acuity of 6/60 or better at 3 months after the initiation of therapy. A retinal detachment developed in one of the eyes which received intravitreal therapy.

CONCLUSIONS

Intravitreal pefloxacin may be a useful aternative therapy in bacteria endophthalmitis.

Pefloxacin clinical pharmacokinetics

Pefloxacin has a broad spectrum of activity against a great number of Gram-negative and Gram-positive bacteria. It is also capable of penetration into cells, yielding high tissue:serum ratios, with implications for the treatment of infections caused by intracellular pathogens. Pefloxacin is well absorbed from the gastrointestinal tract. Its elimination half-life ranges from 6.2 to 12.4 hours. After repeated administration, a major change in pharmacokinetic parameters is observed. Pharmacokinetic parameters are minimally altered or not altered in patients with impaired renal function. Altered plasma pharmacokinetics in patients with liver insufficiency and in elderly patients are observed, so dosage adjustments are necessary. In addition, pefloxacin interacts with a number of other compounds at hepatic (e.g. theophylline and cimetidine) and gastrointestinal (e.g. antacids) sites. With the exception of saliva, cerebrospinal fluid, aqueous humor, vitreous fluid and amniotic fluid, body fluid concentrations reach plasma concentrations. Studies on tissue penetration show that concentrations exceeding plasma concentrations are obtained in most tissues. The highest tissue:plasma concentration ratios are achieved in lung and kidney, whereas concentrations in fat are considerably lower than those in plasma.