Nóra Szentmáry1, Márta Kraszni, Zoltán Zsolt Nagy. 1. First Department of Ophthalmology, Semmelweis University Budapest, Tömõ utca 25-29, 1083 Budapest, Hungary. nszentmary@hotmail.com
Abstract
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.
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.
Authors: J L Vázquez; S Merino; O Domenech; M Berlanga; M Viñas; M T Montero; J Hernández-Borrell Journal: Int J Pharm Date: 2001-06-04 Impact factor: 5.875