Would Beta Blocker Eye drops Be a Breakthrough for the Acute Treatment of Migraine?
Currently, the medications used to treat acute migraine generally are either triptans or nonsteroidal antiinflammatories( NSAIDs). Triptans act by constricting blood vessels and blocking the release of calcitonin generelated peptide( CGRP) from the nerves activated during migraine. CGRP cause blood vessels to swell and initiates the cascade of inflammatory events leading to pain. The NSAIDs are believed to work primarily by blocking the synthesis of another inflammatory pathway mediated by prostaglandins. If beta blockers are found to be an effective acute treatment for migraine, their efficacy would likely be due to a novel mechanism( s) and provide a third line of potential treatment success. This finding would undoubtedly represent a major medical advancement for the acute treatment of migraine.
Also, because beta blockers are already used on a daily basis to prevent migraine, it is unlikely that their frequent use to treat acute migraine would be associated with medication-overuse headache. This finding would be welcome news for those individuals with high treatment requirements. The beta blocker eye drops also would likely have a good tolerability profile as the dose of actual medication received would be quite low relative to oral beta blocker therapy. Clearly, the need to obtain good clinical trials is indicated before making claims for their use or safety.
What Are the Risks and Limitations?
Oral beta blocker therapy is not tolerated by everyone. Beta blockers can lower blood pressure and slow the heart rate. These effects have been occasionally noted with beta blocker eye drops as well. Rarely, beta blockers can have an adverse effect on asthma. Finally, for those patients with diabetes who are prone to hypoglycemia( low blood sugar), beta blockers can mask some of the warning symptoms and would have to be used with caution. However, beta blockers, and in particular timolol, have been used for decades on a daily basis for treatment of glaucoma, and are generally well-tolerated even with daily use. It is assumed that as an acute treatment for migraine, the beta blocker eye drops would be used on an intermittent basis which should increase their tolerability. In the future, studies may be conducted on the administration of beta blockers as a nasal spray.
What Are the Next Steps?
As with any new potential treatment, the next step is rigorous clinical studies. However, much of the initial work has probably been accomplished, and can be extrapolated from completed studies of beta blocker in glaucoma patients and in migraine patients using beta blockers for migraine prevention. However, the initial step is to undertake a pilot study to establish a proof of concept that timolol eye drops are indeed effective as acute treatment of migraine. If that conclusion can be established, large clinical trials must be undertaken to further establish efficacy and safety of their use in acute migraine. Efforts are currently underway to conduct a pilot proof of concept study. If the proof of concept is established, then involvement of the FDA will be needed before the beta blocker eye drops could be an approved treatment of acute migraine.
references
Hagan JC III. Are drops the‘ solution’? A Eureka moment? Beta blocker eye drops for acute migraines. Missouri Med 2014; 111:281-283.
Migliazzo CV, Hagan JC III. Beta blocker eye drops for treatment of acute migraine. Missouri Med 2014; 111:284-289.
Dexter JK, Cady RK. Ophthalmic beta blockers: Treatment for acute migraine? Missouri Med 2014; 111:293-294. HW
18 HeadWise ® | Volume 5, Issue 1 • 2015