Topical diclofenac sodium decreases the substance P content of tears.
OBJECTIVE
To explore the mechanism by which diclofenac sodium eyedrops exert an adverse effect on the cornea.


METHODS
In 10 healthy Japanese volunteers, 0.1% diclofenac sodium solution was instilled into one eye 3 times daily for 2 weeks. Only vehicle was applied to the other eye. Tear samples were taken before drug treatment, at 2 weeks (on the final day of treatment), and at 4 weeks. Prostaglandin E(2) and substance P concentrations in tears were measured using enzyme immunoassays.


RESULTS
After treatment for 2 weeks, concentrations of both prostaglandin E(2) and substance P in tears from diclofenac sodium-treated eyes had decreased significantly, and both had returned to baseline levels by 4 weeks. No significant changes were seen in prostaglandin E(2) and substance P levels in vehicle-treated eyes at any time points.


CONCLUSIONS
Diclofenac sodium eyedrops concurrently reduced concentrations of prostaglandin E(2) and substance P in tears. Depletion of substance P (a pain-associated neurotransmitter) by diclofenac sodium may promote development of corneal complications.
Yamada
Masakazu
M
Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160, Japan. yamadam@sc.itc.keio.ac.jp
Ogata
Masaro
M
Kawai
Masataka
M
Mochizuki
Hiroshi
H
Mashima
Yukihiko
Y
D000287:Administration, Topical; D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage*; D016861:Cyclooxygenase Inhibitors / Q000008:administration & dosage*; D004008:Diclofenac / Q000008:administration & dosage*; D015232:Dinoprostone / Q000378:metabolism; D005136:Eye Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D009883:Ophthalmic Solutions; D013373:Substance P / Q000378:metabolism*; D013666:Tears / Q000187:drug effects* / Q000378:metabolism
D000894:Anti-Inflammatory Agents, Non-Steroidal; D016861:Cyclooxygenase Inhibitors; D005136:Eye Proteins; D009883:Ophthalmic Solutions; C042434:tear proteins; D004008:Diclofenac; D013373:Substance P; D015232:Dinoprostone