Pharmacy & Therapeutics- July 2008 - (Page 405) CONTINUING EDUCATION CREDIT the assistance of physicians who have experience in headache management. Migraine may remain undiagnosed in many patients because of a wide continuum of presentations, often resulting in an improper diagnosis of sinus or tension headache. Such misdiagnoses may lead to inadequate or improper treatment.9,10 The Headache Classification Subcommittee of the International Headache Society (IHS) has developed a comprehensive system for classifying migraine that can be useful along with other tools to assist in the diagnostic process.11–14 Migraine may occur in three clinical phases:11 1. The pre-headache phase includes the premonitory phase and the migraine aura. This phase may precede the headache by hours to days, affecting up to 20% to 60% of patients. Features of the premonitory phase are both physical and somatic, compared with the aura phase, which manifests with more neurological features. 2. During the headache phase, the migraine itself usually presents with throbbing, pulsatile pain in the frontotemporal region, usually lasting from 4 to 72 hours. The pain may vary in severity from mild to severe and may escalate over the course of the headache. Other clinical features that may be present during this phase include nausea, vomiting, autonomic symptoms, nasal congestion, and lacrimation.10,11,14 Nausea and vomiting during a migraine are thought to be a result of the direct activation of trigeminal thalamic and spinal thalamic tracts.6 Many female patients experience migraines in relation to their monthly menstrual periods, offering targeted periods for treatment.15 3. The resolution (postdromal) phase consists of fatigue and irritability, lasting a day or two; this is sometimes referred to as the “migraine hangover.”10–12 Although these three phases characterize the stages of migraine, many patients do not present in such a typical fashion; they might experience only some of these clinical features, or the pain might present in a more atypical fashion.10–14 The IHS criteria of the International Headache Classification [ICHD-2]) require two of the four pain characteristics and only one of the two associated symptoms for the clinical diagnosis of migraine.11 Migraine is associated with a wide range of comorbidities, including depression, bipolar disease, fibromyalgia, irritable bowel syndrome, overactive bladder, sleep disorders, obsessive–compulsive disorders, and anxiety, which may have a significant impact on the care of the patient.16,17 Managing the Patient with Headache The initial assessment of patients with headache should include a complete medical evaluation to rule out reversible causes, including rare serious causes such as tumors or other cerebrovascular abnormalities. When migraine is diagnosed, the initial management should involve an assessment of potential triggers or exacerbating factors. Further management should include education for patients and their families, because migraine can have a significant impact on family life.19,23,24 Nonpharmacological treatment. Non-drug therapies include biofeedback, behavior modification, and psychosocial interventions, including relaxation and stress management. These therapies can be effective alone or in combination with medications in some populations.25–27 Other nonpharmacological therapies that may benefit some patients include acupuncture, applications of heat and cold, impulse magnetic-field therapy, photic stimulation, and physical approaches (e.g., aerobic exercise, isometric neck exercises, and chiropractic manipulations).28–36 Patients should take an active role in their care. Developing a headache diary and documenting headache frequency, associated triggers, and response to pharmacotherapy can be an excellent place to start.37 Pharmacotherapy. The pharmacotherapy of migraine involves medications used in acute (abortive) management and other agents that are used in preventative (prophylactic) management. The complex pathophysiology of migraine supports numerous targets for pharmacotherapy. Medications that interact with various vasoactive neurotransmitters—including serotonin, tyramine, norepinephrine, gamma-aminobutyric acid (GABA), N-methyl-D-aspartate (NMDA), dopamine, and many other substances (e.g., bradykinin, histamine, and prostacyclin)—continue to be studied and utilized.38,39 Pharmacists, who are often the first health care contact for migraine patients, should have a good understanding of migraine and its pharmacological management.40 Part 1 of this continuing education article covers the abortive pharmacotherapy of migraine. A subsequent article in next month’s issue of P&T (part 2) will discuss prophylactic (preventative) pharmacotherapy. Acute (Abortive) Migraine Treatment The use of abortive therapy alone in the acute management of migraine may be an appropriate option for patients who experience fewer than two migraines per month or who use abortive medications less than two days per week. Other important factors to be considered include the effectiveness of abortive medications, a patient’s tolerance to these agents, the migraine’s disabling effects, and interference with daily routines.39 The appropriate choice depends on one’s history of abortive and concurrent medication use, comorbidities, contraindications, associated symptoms (e.g., nausea and vomiting), the severity and frequency of attacks, and cost.6–8,10, 35,36,38,41,42 Migraine Triggers and Precipitating Factors The therapeutic approach to migraine should always include an evaluation of potential triggers or precipitating factors. Although limited evidence implicates the role of diet as a trigger, some patients report benefits when they avoid certain foods and their chemical content. Numerous chemical substances found in various foods or medications, psychological and physical factors, and other triggers may exacerbate or precipitate migraine; an exhaustive list is beyond the scope of this article. Clinicians should evaluate patients for factors that might be causing or contributing to migraine.18–23 Table 1 lists common pharmacotherapies used in the abortive management of migraine, including the simple and various combination analgesics, nonsteroidal anti-inflammatory drugs (NSAIDs), ergot derivatives, 5-hydroxytriptamine (5-HT) receptor agonists (triptans), antiemetic agents, and Vol. 33 No. 7 • July 2008 • P&T® 405
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