Intraocular pressure effects of multiple doses of drugs applied to glaucomatous monkey eyes
P. Y. Lee, S. M. Podos, J. B. Serle, C. B. Camras and C. H. Severin
The effects of multiple dosing with 0.5% timolol maleate, 2% epinephrine
hydrochloride, 4% pilocarpine hydrochloride, 1% vanadate, 1% forskolin
(nonproprietary name, colforsin), or 0.5% prostaglandin F2 alpha on
intraocular pressure (IOP) were each tested on eight cynomolgus monkey eyes
in which glaucoma was induced by photocoagulating the trabecular meshwork
with the argon laser. The week prior to drug therapy, baseline IOP
measurements were carried out at hourly intervals from 9:30 am to 3:30 pm
on three days. One to two days later, therapy was initiated. Each drug was
applied topically to both eyes of each monkey twice daily for at least four
days. The IOP was measured with a calibrated pneumatonometer at the same
hourly intervals on treatment days as on the baseline days. The IOP at each
time of day on treatment days was compared with the average baseline IOP
measured at the corresponding time of day. Topical application of timolol,
epinephrine, pilocarpine, vanadate, and prostaglandin F2 alpha
significantly reduced IOP without evidence of tolerance or tachyphylaxis
during the course of therapy. Forskolin did not significantly decrease IOP
after the second day of treatment.
