What is it about?
Timolol eye drops are widely used in the treatment of glaucoma (“eye pressure disease”), which is the second leading cause of world blindness. Timolol applied on cornea decreases intraocular pressure in the eye. However, 80% of timolol is absorbed from local application sites to the rest of the body at large, which may lead to high timolol concentration in blood. Therefore, patients using ophthalmic timolol may suffer from serious adverse effects on heart such as slow heartbeat and conduction blocks between atria and ventriculum. These patients are at high risk of developing drop in blood pressure, fainting and falls associated with getting up.
Featured Image
Why is it important?
During the past decade, a large number of clinical studies and patient case reports of ophthalmic timolol have been published. They have significantly expanded the knowledge of the critical role of ophthalmic timolol in serious cardiac adverse effects in various patients. In addition, the pharmacokinetics of ophthalmic timolol has been elucidated in detail both in vitro and in vivo. The role of polymorphically expressed cytochrome P450 2D6 (CYP2D6) in timolol metabolism and its clinical consequences has been further clarified. We highlight glaucoma patient groups, who are at particular risk to have timolol- related serious cardiac adverse effects. Finally, we present risk mitigation activities, which should be performed before and after starting the treatment with ophthalmic timolol.
Perspectives
Physicians, including ophthalmologists, other health care professionals and patients may think that ophthalmic timolol is “just an eye drop”, affecting only in the eye, even though it may cause serious cardiac adverse effects. Recently, new glaucoma combination products containing timolol and other glaucoma drugs, such as prostaglandin analog tafluprost, have been launched. However, for some reason the cardiac safety of the combination products has not been discussed in the papers, which have focused on the safety of these drugs. In our opinion, the cardiac safety of combination products should be further evaluated. We also encourage pharmaceutical companies to consider developing safer combination products. This could be done by increasing the viscosity of the combination product solution, which would enable to use lower timolol concentration in the eye drop. The cardiac safety of glaucoma patients would be increased, while the efficacy of the product would not be compromised.
Jukka Mäenpää
AstraZeneca
Read the Original
This page is a summary of: Cardiac safety of ophthalmic timolol, Expert Opinion on Drug Safety, August 2016, Taylor & Francis,
DOI: 10.1080/14740338.2016.1225718.
You can read the full text:
Contributors
The following have contributed to this page
