Topical Administration Of Latanoprost Research Articles

Effects of prostaglandin-mediated and cholinergic-mediated miosis on morphology of the ciliary cleft region in dogs.

OBJECTIVE To compare morphology of the ciliary cleft (CC) region in dogs after topical administration of latanoprost, pilocarpine, or a combination of latanoprost and pilocarpine. ANIMALS 6 Beagles. PROCEDURES A prospective 4-phase crossover study with washout periods was performed. Latanoprost (phase L), pilocarpine (phase P), pilocarpine followed by latanoprost (phase PL), and latanoprost followed by pilocarpine (phase LP) were administered to the right eye. Artificial tears were administered to the left eye (control eye). For each phase, pupil diameter and intraocular pressure (IOP) were measured and ultrasonographic biomicroscopy was performed 2 hours after topical treatment. Angle opening distance (AOD), ciliary cleft width (CCW), ciliary cleft length (CCL), and ciliary cleft area (CCA) were evaluated. RESULTS All treated eyes had marked miosis without significant differences in pupil diameter among phases. Significant IOP reductions were detected for all phases, except phase P. The AOD and CCA were significantly increased in all phases for treated eyes, compared with results for control eyes. The CCW was significantly increased in phases P, PL, and LP; CCL was significantly increased in phases PL and LP. Comparison of treated eyes among phases revealed that CCW differed significantly between phases L and P and between phases L and PL. CONCLUSIONS AND CLINICAL RELEVANCE Prostaglandin-mediated and cholinergic-mediated miosis caused variations in CC configurations. When latanoprost and pilocarpine were used in combination, the first drug administered determined the cleft morphology, which was not fully reversed by the second drug. The CC morphology did not fully explain IOP reductions.

Effect of topical anti-glaucoma medications on late pupillary light reflex, as evaluated by pupillometry.

The late post-illumination pupillary response (PIPR 10-30s ) to blue light is reduced in glaucoma, suggesting that pupillometry can be used in clinical glaucoma evaluation. Since animal studies have indicated that common anti-glaucomatous agents affect the iris muscle, we investigated the short-term effect of the anti-glaucoma drugs on the pupillary light reflex and in particular on the PIPR10-30s. In this randomized, double-masked, crossover trial, pupillometry was performed before and after topical administration of latanoprost, dorzolamide, and timolol in 20 healthy subjects. Stimulus was blue (463 nm) and red light (633 nm) of 2 log (lux). Main outcome was the PIPR10-30s to blue light. Additionally, pupil size, maximal contraction, and the early post-illumination pupillary response (PIPR 0-10s ) to blue and red light were investigated. Pupil response variations between 8 a.m. and 2 p.m. were also assessed. Intraocular pressure (IOP) was measured before and 3.5 h after drug instillation. We found no drug effect on the blue light PIPR10-30s or any other blue light pupil parameters. During the control day, the only significant variation over time was observed for the red light PIPR0-10s (p = 0.02). Pupillary size decreased slightly with timolol (0.1 mm, p = 0.03) and dorzolamide (0.2 mm, p < 0.001), but not with latanoprost. Timolol also reduced the maximal contraction amplitude significantly during red light (p = 0.02). Intraocular pressure was significantly reduced by all three drugs after 3.5 h (p < 0.01), while it remained unchanged during the control day (p = 0.3). Anti-glaucoma medications did not interfere with the blue light elicited PIPR. Dorzolamide reduced pupil size, while timolol reduced both pupil size and maximal contraction to red light, but the effect was minute and not of clinical importance.

Effects of concomitant administration of latanoprost and pilocarpine on the intraocular pressure of experimentally glaucomatous rabbits

Summary The purpose of this study was to evaluate the effects of a combination of latanoprost and pilocarpine on the intraocular pressure in experimentally glaucomatous rabbits. Ocular hypertension was induced in 11 conscious rabbits by the oral administration of tap water (70 mL/kg) via an orogastric tube. The study was conducted in three therapeutic groups to test the effects of latanoprost (group L), pilocarpine (group P) and a combination of the two drugs (group LP). After evaluating the first drug, a washout period of 1 week was allowed before the second drug was evaluated. The left eye of rabbits in group L received one drop of normal saline and one drop of 0.005% latanoprost, in group P one drop of normal saline and one drop of 2% pilocarpine and in group LP, one drop of 0.005% latanoprost and one drop of 2% pilocarpine. The right eyes of all rabbits received two drops of normal saline (as control eyes). The intraocular pressure (IOP) and pupil diameter (PD) were measured before and at 0, 15, 30, 45, 60, 75, 90, 105 and 120 min post-water loading. The results showed that eyes, which received pilocarpine had a significantly lower increase in IOP at 15, 30, 45 and 60 min after drug administration compared to placebo eyes, whereas groups L and LP did not prevent an IOP increase. The PD decreased in groups P and LP throughout the study, whereas it did not change in group L. It was concluded that the topical administration of latanoprost alone or in combination with pilocarpine appeared to have no effect on IOP in acute ocular hypertensive rabbits.

Effects of topical administration of 0.005% latanoprost solution on eyes of clinically normal horses.

To determine the effect of 0.005% latanoprost solution on intraocular pressure (IOP) of eyes of clinically normal horses and establish the frequency of adverse effects of drug administration. 20 adult clinically normal horses. IOP was recorded (7, 9, and 11 AM; 3, 5, and 7 PM) on days 1 and 2 (baseline), days 3 to 7 (treatment), and days 8 to 9 (follow-up). Latanoprost was administered to 1 randomly assigned eye of each horse every 24 hours during the treatment period, following the 7 AM IOP recording. Pupil size and the presence or absence of conjunctival hyperemia, epiphora, blepharospasm, blepharedema, and aqueous flare were recorded prior to IOP measurement. IOP was reduced from baseline by a mean value of 1.03 mm Hg (5%) in males and 3.01 mm Hg (17%) in females during the treatment period. Miosis developed in all treated eyes and was moderate to marked in 77% of horses, with the peak effect observed 4 to 8 hours after drug administration. Conjunctival hyperemia, epiphora, blepharospasm, and blepharedema were present in 100, 57, 42, and 12% of treated eyes, respectively, 2 to 24 hours following drug administration. Aqueous flare was not observed at any time point. Although IOP was reduced with every 24-hour dosing of latanoprost, the frequency of prostaglandin-induced adverse events was high. Because recurrent uveitis appears to be a risk factor for glaucoma in horses, topical administration of latanoprost may potentiate prostaglandin-mediated inflammatory disease in affected horses.

Induction of Tyrosinase Gene Transcription in Human Iris Organ Cultures Exposed to Latanoprost

Topical administration of latanoprost sometimes induces gradual iris darkening. The present study was undertaken to determine if latanoprost can increase transcription of the gene for tyrosinase, an important enzyme in the biosynthesis of melanin. Results from brown, hazel, and blue irides were compared. Iris tissue was isolated from 30 pairs of postmortem human donor eyes, and 2 iris segments from each eye were incubated in tissue culture medium supplemented with 200nM latanoprost acid or vehicle for 7 days. Tyrosinase messenger RNA (mRNA) was determined using real-time polymerase chain reaction analysis (TaqMan quantitative polymerase chain reaction). Results for tyrosinase mRNA were normalized according to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA in each sample. Tyrosinase mRNA expression was similar in blue and hazel irides, and ranged from 0.7-fold to 12.6-fold greater than GAPDH expression. In contrast, control brown iris culture tyrosinase expression ranged from 6.4-fold to 265-fold greater than GAPDH expression. Induction of tyrosinase mRNA by latanoprost was below threshold in all the blue iris cultures (n = 8 pairs), present in 1 of 9 hazel iris cultures, and present in 5 of 13 brown iris cultures. Mean induction in the responding hazel iris cultures was 1.40-fold. Mean induction among the responding brown iris cultures was 2.97-fold. These observations support the view that iris darkening associated with latanoprost treatment reflects induction of tyrosinase expression. Moreover, they suggest that the probability that latanoprost will increase tyrosinase expression is directly related to the magnitude of tyrosinase expression before treatments are initiated. The variability of iris darkening with latanoprost may reflect natural variation in the basal transcription of tyrosinase.

Iris cyst associated with topical administration of latanoprost

PURPOSE: To report an adverse side effect associated with topical latanoprost usage. METHOD: Case report. A 76-year-old woman with primary open-angle glaucoma developed an iris cyst 5 weeks after beginning treatment with latanoprost. Clinical examinations and slit-lamp photographs were performed. RESULTS: Latanoprost was discontinued. Periodic examinations disclosed that the iris cyst gradually diminished and finally disappeared within 3 weeks. CONCLUSION: The formation of an iris cyst is a possible complication of topical latanoprost therapy.

Additive Ocular Hypotensive Effect of Latanoprost and Acetazolamide: A Short-term Study in Patients with Elevated Intraocular Pressure

To investigate the additive ocular hypotensive effect of latanoprost on the intraocular pressure (IOP) reduction induced by a suboptimal dose of acetazolamide, a carbonic anhydrase inhibitor. A short-term, randomized, placebo-controlled, double-masked study. Twenty-four patients with glaucoma with elevated IOPs. Acetazolamide 250 mg twice daily from day 1 to day 18. Topical 50 micrograms/ml latanoprost or placebo eye drops bilaterally instilled once daily from day 4 to day 18. IOP, conjunctival hyperemia. The mean IOP of 19.5 mmHg during acetazolamide treatment was further reduced to 16.8 mmHg after topical administration of latanoprost, i.e., a decrease of 2.9 +/- 2.8 mmHg (15%, P < 0.001). Administration of placebo to patients on acetazolamide resulted in an upward drift of 1.3 mmHg (6%, P = 0.03). A modest but statistically significant increase in conjunctival hyperemia was found in the latanoprost-treated group, but did not affect the masking. This short-term study indicates that the combination of topically applied latanoprost and a suboptimal dose of systemic carbonic anhydrase inhibitor is useful in the management of glaucoma.