STOWE, VT – , said Rebecca Burch, MD, staff attending neurologist at Brigham and Women’s Hospital in Boston. Clinical observation suggests that preventive treatment provides benefits for appropriately selected migraineurs, although few data confirm a modifying effect on disease course, she said at the Stowe Headache Symposium sponsored by the Headache Cooperative of New England. In her overview, Dr. Burch discussed when preventive treatment is appropriate, which patients are candidates for preventive therapy, and what the levels of evidence are for the preventive therapies.
Identifying candidates for preventive treatment
Migraine is the second most disabling condition worldwide and imposes a large social and economic burden, said Dr. Burch. Preventive therapy reduces the disability associated with migraine. It reduces headache frequency and, thus, the risk that episodic migraine will transform into chronic migraine. By reducing the number of headache days, preventive treatment also may reduce the overuse of acute medication, which is a risk factor for migraine chronification.
Neurologists can consider preventive therapy for migraineurs with frequent headaches, but the term “frequent” is not clearly defined. Common definitions include one headache per week and two headaches per month with significant disability. These definitions are based on expert consensus and do not have strong evidential support, said Dr. Burch. Preventive therapy also may be appropriate for migraineurs who overuse acute medication or who have failed acute medications. Special cases, such as patients with exceptional anxiety or disability, may also call for preventive treatment, said Dr. Burch.
Data suggest that preventive treatment for migraine is underused. The American Migraine Prevalence and Prevention study of 2007 found that half of patients who should be offered preventive treatment are currently receiving it. In 2016, the Chronic Migraine Epidemiology and Outcomes study found that 4.5% of chronic migraineurs take both acute and preventive treatment.
Other data published in Cephalalgia in 2015 indicate that adherence to migraine preventive treatment is approximately 20%. About 45% of patients discontinue medication because of side effects, and 45% cite lack of efficacy as their reason for discontinuation. Patients also mentioned cost, interactions with other medications, and the inconvenience of daily medication as other reasons for discontinuation.
Neurologists can take several steps to increase adherence to preventive treatment, said Dr. Burch. First, neurologists should confirm that patients want preventive medication. A clear discussion of the goals of preventive treatment is helpful as well. Furthermore, neurologists should explain that they are offering patients a trial, said Dr. Burch. The medication can be titrated slowly from a low dose to minimize side effects. Patients can be reassured that ineffective medications will be stopped. Neurologists can emphasize that their relationship with the patient is a partnership and that the treatment strategy will be improved over time.
Examining the evidence on treatments’ efficacy
Many drug classes, such as antiepileptics, antidepressants, beta blockers, neurotoxins, and calcitonin gene-related peptide (CGRP) antibodies, include therapies that are used as preventive treatments for migraine. When selecting a medication, a neurologist should start with one that is supported by Level A or Level B evidence, said Dr. Burch. Medications with Level A evidence include divalproex, topiramate, metoprolol, propranolol, erenumab, galcanezumab, fremanezumab, eptinezumab, and onabotulinumtoxinA. Medications with Level B evidence include amitriptyline, venlafaxine, memantine, lisinopril, and candesartan. Neurologists sometimes prescribe gabapentin and verapamil, although the evidence for them is Level U. Duloxetine, nortriptyline, and pregabalin also are used, but the evidence for them has not been evaluated. “We need more evidence in these areas,” said Dr. Burch.