Comparison of pressure lowering effect of latanoprost and a combination of timolol - pilocarpine eye drops in patients insufficiently controlled with B adrenergic antagonists

To compare the effect pressure [IOP] of latanoprost monotherapy and timololpilocarpine in patients with glaucoma or oclular hypertension with inadequately controlled IOP on topical B adrenergic antagonists. This was randomized, observer masked, 6 weeks study performed on 112 patients with glaucoma or ocular hypertension and IOP of at least 22 mmHg on treatment with timolol 0.5 percent twice daily of at least 21 days. The patients were randomized into two parallel groups: either to latanoprost 0.005 percent once daily or to combination of timolol pilocarpine. Changes in mean diurnal IOP from baseline to the 6 week visit were determined. Switching from timolol 0.5 percent to latanoprost 0:005 percent once daily caused a statistically significant reduction in mean IOP [P < 0.001], and switching from timolol to timolol-pilocarpine twice daily caused a statistically significant reduction in mean diurnal IOP [P < 0.001].Latanoprost monotherapy was at least as effective as combination of timolol-pilocarpine twice daily treatment in reducing IOP in patients not adequately controlled on B adrenergic antagonists

Influence of dosage form on the miotic and cardio-pulmonary effects of topically administered pilocarpine

Pilocarpine 2% was administered topically in the form of eye drops and ointment in the same dose. Drops and ointment produced a miotic effect with comparable onset of action [3.7 +/- 1.4 and 3.7 +/- 2 minutes respectively] and onset of maximum miosis [18.4 +/- 2.1 and 19.8 +/- 3.9 minutes respectively]. The duration of the miotic effect of ointment [257.5 +/- 46.9 minutes] was significantly longer than that of drops [162.9 +/- 13.5 minutes]. Thus, ointment had better ocular bioavailability. However, drops had higher systemic bioavailability. Drops significantly decrease heart rate by 30 +/- 11.9% and increased airway resistance by 24.6 +/- 59%. Systemic actions of eye drops could be antagonized by atropine. Ointment insignificantly affected heart rate [-6.9 +/- 6%] and airway resistance [-0.6 +/- 8%]. In conclusion, increasing the viscosity of the pilocarpine's vehicle increases the ocular bioavailability and decrease the systemic one. This led to an increase in its beneficial miotic effect and a decrease in its harmful cardio-pulmonary effects and vice-versa