Migraine is a headache disorder that often causes unilateral pain, photophobia, phonophobia, nausea, and vomiting. More than 70% of office visits for migraine are made to primary care physicians.1 Recent data suggest migraine may be caused primarily by neuronal dysfunction and only secondarily by vasodilation.2 Although there are numerous classes of drugs used for migraine prevention and treatment, their success has been limited by inadequate efficacy, tolerability, and patient adherence.3 The discovery of pro-inflammatory markers such as calcitonin gene-related peptide (CGRP) has led to the development of new medications to prevent and treat migraine.4
Pathophysiology, Dx and triggers, indications for pharmacotherapy
Pathophysiology. A migraine is thought to be caused by cortical spreading depression (CSD), a depolarization of glial and neuronal cell membranes.5 This results in increased cortical excitability, central trigeminal-thalamic sensitization, and defective descending pain modulatory activity.6 The activation of the trigeminal sensory pathways, primarily the ophthalmic branch, sends nociceptive signals to second-order neurons mediated by the release of neurotransmitters, such as CGRPs.5 This activation explains in part the primary location for a migraine, which is around the eye and the neighboring cranial regions. The pain perceived by the patient is caused by these second-order neurons.
Dx and triggers. In 2018, the International Headache Society revised its guidelines for the diagnosis of migraine.7 According to the 3rd edition of The International Classification of Headache Disorders (ICHD-3), the diagnosis of migraine is made when a patient has at least 5 headache attacks that last 4 to 72 hours and have at least 2 of the following characteristics: (1) unilateral location, (2) pulsating quality, (3) moderate-to-severe pain intensity, and (4) aggravated by or causing avoidance of routine physical activity.7 The headache attacks also should have (1) associated nausea or vomiting or (2) photophobia and phonophobia.7 The presence of atypical signs or symptoms as indicated by the SNNOOP10 mnemonic raises concerns for secondary headaches and the need for further investigation into the cause of the headache (TABLE 1).8 It is not possible to detect every secondary headache with standard neuroimaging, but the SNNOOP10 red flags can help determine when imaging may be indicated.8 Potential triggers for migraine can be found in TABLE 2.9
Indications for pharmacotherapy. All patients receiving a diagnosis of migraine should be offered acute pharmacologic treatment. Consider preventive therapy anytime there are ≥ 4 headache days per month, debilitating attacks despite acute therapy, overuse of acute medication (> 2 d/wk), difficulty tolerating acute medication, patient preference, or presence of certain migraine subtypes.7,10
Abortive therapies for migraine include analgesics such as nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen, and ergot alkaloids, triptans, or small-molecule CGRP receptor antagonists (gepants). Prompt administration increases the chance of success with acute therapy. Medications with the highest levels of efficacy based on the 2015 guidelines from the American Headache Society (AHS) are given in TABLE 3.11 Lasmiditan (Reyvow) is not included in the 2015 guidelines, as it was approved after publication of the guidelines.
Non-CGRP first-line therapies
NSAIDs and acetaminophen. NSAIDs such as aspirin, diclofenac, ibuprofen, and naproxen have a high level of evidence to support their use as first-line treatments for mild-to-moderate migraine attacks. Trials consistently demonstrate their superiority to placebo in headache relief and complete pain relief at 2 hours. There is no recommendation for selecting one NSAID over another; however, consider their frequency of dosing and adverse effect profiles. The number needed to treat for complete pain relief at 2 hours ranges from 7 to 10 for most NSAIDs.11,12 In some placebo-controlled studies, acetaminophen was less effective than NSAIDs, but was safer because it did not cause gastric irritation or antiplatelet effects.12
Triptans inhibit 5-HT1B/1D receptors. Consider formulation, route of administration, cost, and pharmacokinetics when selecting a triptan. Patients who do not respond well to one triptan may respond favorably to another. A meta-analysis of the effectiveness of the 7 available agents found that triptans at standard doses provided pain relief within 2 hours in 42% to 76% of patients, and sustained freedom from pain for 2 hours in 18% to 50% of patients.13 Lasmiditan is a selective serotonin receptor (5-HT1F) agonist that lacks vasoconstrictor activity. This is an option for patients with relative contraindications to triptans due to cardiovascular risk factors.10
Continue to: Second-line therapies