Combined timolol and pilocarpine vs pilocarpine alone and timolol alone in the treatment of glaucoma

Fixed Combination of Carteolol and Pilocarpine Eye-Drops: A Double-Blind Randomized Cross-Over Trial versus Carteolol Alone on Intra-Ocular Pressure

The effects of carteolol 2% and a fixed combination of carteolol 2% and pilocarpine 2% (CBS 341 A) eye-drops on intraocular pressure (I.O.P.) were compared in a multicenter double-blind, cross-over prospective trial. Twenty-eight patients were initially selected after at least three weeks of carteolol 2%, with a morning I.O.P. greater than 21-mmHg. They received 2 drops a day (b.i.d.), in a random order, alternating two weeks of carteolol 2% alone or two weeks of CBS 341 A. After each two-week period a 12-h I.O.P. curve was plotted. Compared to carteolol the combination reduced I.O.P. on average by around 20% (4 mmHg), with maximum effect 4h after instillation. The effectiveness was confirmed after twelve hours. Some side effects were reported with CBS 341 A, due to the well known pharmacological effects of pilocarpine. The new combination could be useful for second-line therapy in glaucoma.

Is poor life expectancy a predictive factor in the progression of primary open angle glaucoma?

AIM

To investigate the disease progression and final visual outcome of glaucoma patients with poor life expectancy, compared to matched patients with a longer life expectancy.

METHOD

Visual fields at diagnosis and at the last ophthalmic appointment before death were analysed for glaucoma patients referred between 1991 and 1995, and deceased before the end of 2001. These patients were matched to the patients living beyond 2001. Functional vision was also assessed, and classified as better than the NHS partial sighted criteria.

RESULTS

A total of 61 deceased patients were identified, resulting in 40 matched pairs. In all, 6.5% of the patients with poor life expectancy progressed from functional vision to beyond partial sighted criteria, and none of the matched patients progressed to this extent. At final assessment an association between poor life expectancy and progression beyond functional vision was found existing (P = 0.02), with a lesser association at diagnosis (P = 0.06). Visual field scores of the matched pairs who had test results available for both initial and final assessment (n = 23 pairs) showed no statistically significant difference between the two groups at diagnosis (P = 0.52); However, a significant difference at final the assessment did exist (P = 0.042). No difference between the initial (off medication) intraocular pressures (IOPs) was found (P = 0.82). At the final assessment a significant difference existed (P = 0.025), with the surviving group having a higher final mean pressure (15.9 mmHg, SD 2.8, vs 18.3 mmHg, SD 4.9).

CONCLUSION

Patients with poor life expectancy progressed more than the matched surviving patients, when measured from an initially similar position, despite better IOP control.

Timolol 0.5%/dorzolamide 2% fixed combination versus timolol 0.5%/pilocarpine 2% fixed combination in primary open-angle glaucoma or ocular hypertensive patients

PURPOSE

To establish the efficacy and safety of timolol maleate/dorzolamide fixed combination (TDFC) versus timolol maleate/pilocarpine fixed combination (TPFC), each given twice daily, in primary open-angle glaucoma or ocular hypertensive patients.

METHODS

In this prospective, multicentred, double-masked trial, 37 patients were treated twice daily with timolol for 4 weeks. They were then randomized to one of the treatment medications for 6 weeks, after which they were treated with timolol again for 2 weeks before being placed on the opposite treatment medication for 6 weeks.

RESULTS

A total of 36 patients completed the trial. Their mean baseline intraocular pressure (IOP) was 22.3 +/- 3.7 mmHg. Following 6 weeks of treatment, the mean trough (08.00 hours) IOP was 18.0 +/- 2.2 mmHg for TDFC and 17.4 +/- 2.0 mmHg for TPFC (p = 0.22). The mean diurnal curve IOP was 18.1 +/- 2.2 mmHg for TDFC and 16.7 +/- 1.9 mmHg for TPFC (p = 0.0007). At the remaining time-points (10.00, 18.00 and 20.00 hours), TPFC IOPs were statistically lower than TDFC IOPs (p < 0.03). There were statistically more unsolicited reports of vision change and ocular pain associated with TPFC (p = 0.04). Six patients were discontinued early from TPFC therapy (17%) versus two from TDFC (6%) (p = 0.13).

CONCLUSIONS

This study suggests that TPFC can provide at least a similar efficacious reduction in IOP as TDFC in patients with primary open-angle glaucoma or ocular hypertension.

Meta-analysis of randomised controlled trials comparing latanoprost with timolol in the treatment of patients with open angle glaucoma or ocular hypertension

AIM

To evaluate the comparative efficacy and tolerance of latanoprost versus timolol through a meta-analysis of randomised controlled trials (RCTs).

METHODS

Systematic retrieval of RCTs of latanoprost versus timolol to allow pooling of results from head to head comparison studies. Quality of trials was assessed based on randomisation, masking, and withdrawal. Sensitivity analyses were used to estimate the effects of quality of study on outcomes. The data sources were Medline, Embase, Scientific Citation Index, Merck Glaucoma, and Pharmacia and Upjohn ophthalmology databases. There were 1256 patients with open angle glaucoma or ocular hypertension reported in 11 trials of latanoprost versus timolol. The main outcome measures were (i) percentage intraocular pressure (IOP) reduction for efficacy; (ii) relative risk, risk difference, and number needed to harm for side effects such as hyperaemia, conjunctivitis, increased pigmentation, hypotension, and bradycardia expressed as dichotomous outcomes; and (iii) reduction in systemic blood pressure and heart rate as side effects.

RESULTS

Both 0.005% latanoprost once daily and 0.5% timolol twice daily reduced IOP. The percentage reductions in IOP from baseline (mean (SE)) produced by latanoprost and timolol were 30.2 (2.3) and 26.9 (3.4) at 3 months. The difference in IOP reduction between the two treatments were 5.0 (95% confidence intervals 2.8, 7.3). However, latanoprost caused iris pigmentation in more patients than timolol (relative risk = 8.01, 95% confidence intervals 1.87, 34.30). The 2 year risk with latanoprost reached 18% (51/277). Hyperaemia was also more often observed with latanoprost (relative risk =2.20, 95% confidence intervals 1.33, 3.64). Timolol caused a significant reduction in heart rate of 4 beats/minute (95% confidence interval 2, 6).

CONCLUSION

This meta-analysis suggests that latanoprost is more effective than timolol in lowering IOP. However, it often causes iris pigmentation. While current evidence suggests that this pigmentation is benign, careful lifetime evaluation of patients is still justified.

Prolonged, contemporaneous administration of pilocarpine and timolol increases the aqueous humor pilocarpine levels in rabbits

The purpose of this study was to gather information on the mechanism by which timolol/pilocarpine (TI/PI) combination eyedrops provide additive ocular hypotensive effects. An hypothesis, according to which the combination eyedrops prolong the intraocular permanence of PI as a consequence of decreased aqueous humor secretion induced by TI, was not supported by clear-cut literature evidence. It was thus sought to verify if repeated instillations in albino rabbits of combination TI/PI eyedrops do effectively prolong the turnover of PI. Commercial eyedrops containing 0.68% w/v TI maleate and 2.0% w/v PI hydrochloride, buffered at pH 6.8, and two reference solutions containing PI hydrochloride alone (2% w/v), buffered at pH 5.5 and 6.8, were instilled b.i.d. in albino rabbits for five days. Aqueous humor samples, analyzed after the last treatment, showed that the aqueous humor PI levels observed after administration of the combination eyedrops were significantly higher than those resulting from administration of the reference formulations. When compared with the pH 6.8 reference solution, the pH 5.5 one produced slightly higher and more sustained drug levels in the aqueous humor. The present results appear to confirm the assumption that an increased retention of PI in the aqueous humor is responsible for the additive effects on intraocular pressure reported by several authors for the combination TI/PI eyedrops.

Effects of pilocarpine and other antiglaucoma drugs on cultured human Tenon's fibroblast cells

It has been found that long-term therapy with topical antiglaucoma drugs may decrease the success of glaucoma filtering surgery. In this study, various antiglaucoma drugs, including carteolol, betaxolol, levobunolol, pilocarpine, and timolol, were investigated for their proliferative effect on cultured human Tenon's fibroblast cells. It was found that the 3H-thymidine uptake of cultured fibroblast cells was inhibited by commercial antiglaucoma drugs, including carteolol of 0.1% concentration (13%), 0.01% (50%) and 0.001% (53%), betaxolol of 0.05% concentration (14%), 0.005% (42%) and 0.0005% (62%), levobunolol of 0.05% concentration (2%), 0.005% (32%) and 0.0005% (55%), and timolol of 0.025% concentration (4%), 0.0025% (47%) and 0.00025% (55%), whereas the 3H-thymidine uptake was increased by commercial pilocarpine eyedrop from 103% (0.2% of concentration), 170% (0.02% of concentration) to 171% (0.002% of concentration), when cells were treated with commercial drugs for 100 min. Meanwhile, the proliferations of cultured fibroblast cells were stimulated by simultaneously combining 0.2%, 0.02% and 0.002% concentrations of pilocarpine eyedrops with other antiglaucoma drugs, such as carteolol of 0.1% concentration (50%), 0.01% (113%) and 0.001% (138%), betaxolol of 0.05% concentration (24%), 0.005% (128%) and 0.0005% (142%), levobunolol of 0.05% concentration (32%), 0.005% (87%) and 0.0005% (119%), and timolol of 0.025% concentration (15%), 0.0025% (94%) and 0.00025% (118%). Following incubation with pure pilocarpine, the proliferation of Tenon's fibroblast cells was inhibited for 84% (0.2% concentration), 84% (0.02% concentration) and 90% (0.002% concentration). When fibroblast cells were treated with commercial pilocarpine eyedrops for 24 hours, the 3H-thymidine uptake was increased to 160% (0.02% concentration) and 172% (0.002% concentration). This result shows that the commercial pilocarpine may play a crucial role for the proliferation of cultured human Tenon's fibroblast cells.