Long-term drift and timolol therapy: possible role for pulsed therapy

Abstract

Eyes treated with a topical betablocker may exhibit the phenomenon of longterm drift, leading to loss of intraocular pressure control. It has been suggested that discontinuation of the betablocker may restore sensitivity to betablocker therapy, and that this phenomenon might be enhanced by the administration of an adrenergic agonist during this holiday period. This study was set up to examine further this hypothesis. Nine patients with ocular hypertension receiving treatment with timolol were entered into the study. Timolol was discontinued then re-started after four weeks of treatment with dipivefrin. This treatment cycle was repeated after a further four weeks. IOP was measured every two weeks. Re-introduction of timolol was associated with a significant lowering of IOP at two weeks (3.2 mmHg in the first cycle, p < 0.01, 3.4 mmHg in the second cycle, p < 0.01). Discontinuation of timolol and treatment with dipivefrin was not associated with a significant change in IOP.

A 6-month randomized clinical trial of bimatoprost 0.03% versus the association of timolol 0.5% and latanoprost 0.005% in glaucomatous patients

“…Patients treated with topical beta-blockers may exhibit the phenomenon of long-term drift [1] leading to loss of IOP control, and to avoid this possible bias we enrolled in the study only patients on timolol topical therapy with an IOP !21 mmHg but at least 20% lower than the IOP measured before the beginning of the treatment.…”