Interaction of indomethacin and ciprofloxacin in the cornea following phototherapeutic keratectomy.
BACKGROUND
We report a case in which stromal deposits were produced due to drug interaction in a 61-year-old patient following phototherapeutic keratectomy (PTK).


METHODS
In our case, the patient herself added the use of indomethacin eye drops to the prescribed topical antibiotic treatment and eye gel (5x ciprofloxacin plus 3x indomethacin, eye gel overnight) following PTK. At 5 days the central stroma was not reepithelialised; instead, whitish, round deposits were found in the stroma. Mixing indomethacin and ciprofloxacin eye drops 1:1, the pH of the mixture changed to 5.6, and a yellow precipitate was formed; this was analysed by (1)H-NMR spectroscopy. To investigate the solubility of the two drugs at the pH of the mixture, the pH of each solution was independently set to 5.6 by addition of hydrochloric acid or sodium hydroxide.


RESULTS
In the precipitate both indomethacin and ciprofloxacin were detected. After setting the pH to 5.6, a yellow precipitate was observed in the indomethacin solution; however, the ciprofloxacin solution remained clear.


CONCLUSIONS
Interaction may occur if ciprofloxacin and indomethacin are used together. It is better to avoid the use of the two drugs at the same time, particularly in the case of a large epithelial defect when stromal deposition of the drugs may be produced.
First Department of Ophthalmology, Semmelweis University Budapest, Tömõ utca 25-29, 1083 Budapest, Hungary. nszentmary@hotmail.com
Nóra
N
Szentmáry
Márta
M
Kraszni
Zoltán Zsolt
ZZ
Nagy
D000890:Anti-Infective Agents / Q000737:chemistry / Q000627:therapeutic use*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry / Q000627:therapeutic use*; D011232:Chemical Precipitation; D002939:Ciprofloxacin / Q000737:chemistry / Q000627:therapeutic use*; D003315:Cornea / Q000187:drug effects* / Q000601:surgery; D004347:Drug Interactions; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007213:Indomethacin / Q000737:chemistry / Q000627:therapeutic use*; D054018:Lasers, Excimer; D009682:Magnetic Resonance Spectroscopy; D008875:Middle Aged; D018903:Photorefractive Keratectomy; D014945:Wound Healing / Q000187:drug effects
D000890:Anti-Infective Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D002939:Ciprofloxacin; D007213:Indomethacin