CAN THE CONCENTRATION OF TIMOLOL OR THE FREQUENCY OF ITS ADMINISTRATION BE REDUCED

Background: There is evidence that the ocular hypotensive effect of to pical beta-blockers persists for at least 24 hours once beta-blockade has been achieved. In previous studies, the highest concentration of d rug generally has been used for this purpose. Method: Home tonometry w as performed with a self-tonometer by 14 patients to study the intraoc ular pressure (IOP) reduction of 0.5% timolol administered once daily in the morning or in the evening and of 0.25% timolol administered in the morning. The study was masked and included washout periods before and between the different regimens. At the end of each treatment perio d, the IOP was monitored five times daily for 3 days. Results: No sign ificant difference in mean reduction of IOP was found between the morn ing instillation of once daily 0.5% timolol compared with evening inst illation of 0.5% timolol. In addition, there was no statistically sign ificant difference in the mean IOP reduction between once daily admini stration of 0.25% versus 0.5% timolol. Conclusion: This study indicate s that a lower concentration of timolol maleate used once daily may ac hieve maximum IOP reduction. The time of the single administration app ears not to make any difference.