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Timolol eye drops: bradycardia or tachycardia?
Documenta Ophthalmologica. Advances in Ophthalmology
|April 15, 1980
Summary
Timolol eye drops may cause a significant reflex tachycardia upon withdrawal, a rebound phenomenon not previously documented. Caution is advised when prescribing timolol for glaucoma patients with existing arrhythmias.
Area of Science:
- Ophthalmology
- Pharmacology
Background:
- Glaucoma management often involves topical beta-blockers like timolol.
- Understanding the long-term effects and potential side effects of timolol is crucial for patient care.
Purpose of the Study:
- To investigate the effects of timolol 0.25% and 0.50% eye drops on intraocular pressure (IOP), tachyphylaxis, and cardiovascular parameters.
- To identify any significant rebound phenomena after cessation of timolol therapy.
Main Methods:
- A prospective study involving 14 patients (26 eyes) with primary open-angle glaucoma or glaucoma suspect.
- Patients received twice-daily timolol 0.25% or 0.50% for at least 6 months without concomitant medications.
- Monitoring included intraocular pressure, blood pressure, and pulse rate, with special attention to tachyphylaxis and withdrawal effects.
Main Results:
- A slight, non-significant tendency towards tachyphylaxis (1-2 mm Hg) was observed after one week of treatment.
- Intraocular pressure returned to baseline levels 1-2 weeks after timolol withdrawal.
- No significant changes in blood pressure were noted, but a significant reflex tachycardia (10 beats/minute) occurred upon withdrawal.
Conclusions:
- Timolol therapy for glaucoma did not show significant tachyphylaxis or blood pressure changes.
- A significant and previously unreported reflex tachycardia upon withdrawal of timolol eye drops was observed.
- Care should be taken when prescribing timolol eye drops to glaucoma patients with concurrent arrhythmias due to the potential for rebound tachycardia.