Damien O’Brien MPSI looks at prevention, diagnosis and treatment of migraine
Introduction
Migraine is a chronic, episodic neurological disorder characterised by recurrent moderate-to-severe headaches accompanied by sensory and systemic symptoms. It affects an estimated 12- to-15 per cent of the Irish population, making it one of the most common and disabling health conditions encountered in primary care. It is approximately three times more prevalent in women than in men, with the highest incidence typically observed in early to mid-adulthood, often diminishing later in life. Despite its frequency and impact, migraine often remains underdiagnosed and undertreated.
Migraine is recognised as one of the top causes of disability worldwide.
Beyond the pain itself, it imposes a substantial personal and socioeconomic burden through reduced quality of life, lost productivity, absenteeism and increased healthcare costs. It is frequently associated with comorbidities such as anxiety, depression, sleep disorders and cardiovascular disease. These associations can complicate management and contribute to the
chronic nature of migraine. Pharmacists are uniquely positioned to distinguish migraine from other headache types, advise on appropriate self-care, counsel on acute treatment, identify red-flag symptoms, and support referral for preventive therapy.
Clinical presentation
Migraine typically presents as a pulsating, unilateral headache of moderate-to-severe intensity, lasting from four-to-72 hours. The pain is often accompanied by nausea, vomiting, photophobia, phonophobia and osmophobia, and is worsened by physical exertion. It is a debilitating condition involving complex and recurrent neurological events that can significantly impair quality of life. Approximately one-in-four patients experience aura, consisting of transient neurological disturbances such as visual changes, sensory symptoms or language disturbances. Migraine commonly follows four distinct phases:
- Prodrome: Occurs hours to days before onset, with symptoms of fatigue, irritability, mood changes, food cravings and yawning.
- Aura: Present in around 25 per cent of cases, lasting up to 60 minutes. It is fully reversible and can precede or accompany the headache phase. fHeadache phase: The main symptomatic period, often disabling and lasting for hours to days.
- Postdrome: Characterised by movement-sensitive pain in the same location as the headache, with other symptoms including exhaustion, dizziness and euphoria.
The frequency and severity of migraine attacks vary widely, from episodic migraine (fewer than 15 headache days per month) to chronic migraine, defined as 15 or more headache days per month for more than three months, with migraine features on at least eight days per month. Menstrual migraine is a subtype directly linked to hormonal fluctuations, typically occurring in the days before or during menstruation.
Pathophysiology
The precise mechanisms underlying migraine are complex and multifactorial, involving genetic, vascular and neurological components. Dysfunction of the trigeminovascular pain pathway plays a central role. Activation of trigeminal sensory nerves leads to the release of inflammatory neuropeptides such as calcitonin gene-related peptide (CGRP), substance P and neurokinin A. This cascade promotes vasodilation, neurogenic inflammation, and enhanced transmission of pain signals to the brainstem. Functional imaging studies have demonstrated activation in regions such as the brainstem, thalamus and hypothalamus, which helps explain associated symptoms such as nausea, fatigue and sensory hypersensitivity.
Genetic susceptibility also plays a significant role, with up to 50 per cent of first-degree relatives of migraine sufferers affected. Specific genetic mutations have been identified in familial hemiplegic migraine, underscoring the hereditary basis of the disorder. Exposure to or withdrawal from various triggers can precipitate migraine attacks. Common factors include stress, hormonal fluctuations, missed meals, changes in sleep, weather variations, light exposure, alcohol consumption and certain odours.
Diagnosis
Migraine is primarily a clinical diagnosis, based on characteristic symptom patterns rather than imaging or laboratory testing. The International Classification of Headache Disorders (ICHD-3) provides diagnostic criteria based on these features. The diagnosis of chronic migraine requires headache on at least 15 days per month for more than three months, with at least eight days meeting of migraine. A migraine diary can assist in documenting attack frequency, triggers and treatment response. Neuroimaging is not routinely indicted unless atypical or red-flag symptoms are present. These include new-onset headache in patients aged 50 years or older, systemic or meningeal signs, headache not responding to standard treatment, duration beyond 72 hours, or significant changes in the frequency, pattern or severity of attacks.
Acute management
The primary objective of acute migraine management is to achieve rapid and consistent relief of pain and associated symptoms, restoring normal function with minimal adverse effects. Treatment should be individualised according to attack severity, frequency, comorbidities and prior response. Early intervention improves treatment efficacy. A stepwise approach is recommended, beginning with simple analgesics and progressing to triptans and adjunctive therapies as needed. As with diagnosis, maintaining a headache diary can help assess treatment effectiveness.
Menstrual migraine is a subtype directly linked to hormonal fluctuations, typically occurring in the days before or during menstruation
First-line acute treatment includes paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs)
such as aspirin, ibuprofen, naproxen and diclofenac. NSAIDs inhibit cyclooxygenase (COX-1 and COX-2) enzymes, reducing prostaglandin- mediated inflammation and pain. This addresses both the nociceptive and inflammatory components of migraine. Combination therapy with paracetamol and an NSAID may provide enhanced relief. Aspirin should be avoided in patients under 16 years of age due to the risk of Reye’s syndrome.
Triptans are a cornerstone of acute migraine therapy. They act as agonists at serotonin 5-HT1B and 5-HT1D receptors in cranial blood vessels and nerve terminals, causing vasoconstriction and inhibition of neuropeptide release within the trigeminovascular system. Common oral options include sumatriptan
and zolmitriptan. For best results, triptans should be taken as early as possible in the headache phase, with onset of action typically within 30–60 minutes. If symptoms recur, a second dose may be taken after two hours up to a maximum of two doses in 24 hours. If one triptan is ineffective, an alternative agent or formulation may be tried as individual responses vary.
Triptans are contraindicated in patients with ischaemic heart disease, cerebrovascular disease or uncontrolled hypertension.
Antiemetics have an important role to play in acute migraine treatment, including metoclopramide, chlorpromazine, prochlorperazine and domperidone. They alleviate nausea and vomiting associated
with migraine. Furthermore, agents with prokinetic properties, notably metoclopramide, may also improve gastric motility, enhancing absorption of oral medications. This is particularly beneficial as gastric stasis can occur during migraine attacks, delaying drug onset. Antiemetics may therefore be considered even in the absence of significant nausea, to optimise the efficacy of other acute treatments.
Special consideration in acute management
In the presence of nausea and vomiting, drug absorption may be significantly reduced — an important consideration in acute migraine management. To overcome this, non-oral formulations such as nasal sprays, subcutaneous injections and rectal suppositories may be recommended to improve treatment efficacy and onset of action.
Menstrual migraine typically occurs between two days before and three days after menstruation. These attacks may be more severe, longer lasting and less responsive to standard acute therapy. Triptans are the cornerstone of treatment, with agents such as naratriptan and frovatriptan offering advantages due to their prolonged half-life. They may be taken perimenstrually for short-term prophylaxis. NSAIDs may be used at the same time, either alone or in combination with triptans, to enhance symptom relief.
Alongside medication, self-care interventions play an important supportive role in migraine management. Resting in a quiet, dark room and minimising sensory stimuli can help relieve photophobia and phonophobia. Applying a cool compress to the forehead or neck, maintaining hydration and sleeping may also ease symptoms. Identifying and avoiding common triggers — such as irregular meals, dehydration, alcohol or stress — can reduce the severity or frequency of attacks.
Regular or excessive use of acute migraine treatments can lead to medication overuse headache, characterised by increasing headache frequency and reduced responsiveness to therapy. It most commonly occurs when analgesics or triptans are used on more than 10-to-15 days per month. Opioids, including codeine, carry a particularly high risk and should be avoided in migraine management. Patients should be counselled to limit acute medication use to two days per week or fewer, and to seek medical review if headaches become more frequent or refractory.
Preventive management
Preventive therapy aims to reduce the frequency, severity and duration of migraine attacks, with the goal
of improving quality of life in those with frequent or disabling symptoms. Preventive management should be considered when patients experience more than four migraine days per month, when attacks are prolonged or inadequately controlled with acute treatment, or when acute medication is contraindicated or overused. Management should combine pharmacological and lifestyle measures, tailored to individual comorbidities and treatment objectives.
First-line preventive options include certain beta-blockers, anticonvulsants and antidepressants. Propranolol is often used and is an effective treatment option, typically with doses up to 160mg per day. It is particularly useful in patients with hypertension or anxiety. Other beta- blockers such as metoprolol or atenolol may also be considered. Common adverse effects include hypotension, fatigue and dizziness.
First-line preventive options include certain beta-blockers, anticonvulsants and antidepressants
Topiramate is an anticonvulsant that can be an effective preventive intervention, with doses up to 100mg daily in two divided doses. It requires gradual titration and counselling on potential adverse effects, which can include cognitive slowing, paraesthesia, loss of appetite and teratogenicity.
Amitriptyline is another first-line option for migraine prophylaxis. The recommended dose is 10-to-75mg daily, in one or two divided doses, with gradual titration. Doses above 100mg should be used with caution. It is often taken at night due to its sedative properties and may be particularly beneficial in patients with comorbid insomnia, tension-type headache, or depression. Adverse effects such as sedation, weight gain and constipation may limit use.
When first-line interventions are ineffective or poorly tolerated, candesartan and sodium valproate may be considered. Candesartan is particularly useful in patients with comorbid hypertension. Sodium valproate is contraindicated in women of childbearing potential unless no suitable alternative exists, and strict pregnancy prevention measures are in place. Gabapentin is not recommended for the prophylactic treatment of migraine.
Calcitonin gene-related peptide (CGRP) monoclonal antibodies have represented a major advance in preventive migraine therapy. These agents target the CGRP ligand or its receptor, interrupting a key pathway in migraine pathogenesis. Examples include erenumab, fremanezumab, galcanezumab and eptinezumab. They are typically reserved for patients experiencing at least four migraine days per month and only if at least three preventive medicines have failed, are not tolerated or are unsuitable.
Relaxation training and cognitive behavioural therapy may be beneficial, particularly when stress is a contributing factor
Erenumab, fremanezumab and galcanezumab are typically administered subcutaneously once monthly, while eptinezumab is given every three months via intravenous infusion. Clinical benefit is usually seen within weeks. Treatment response should be assessed after 12 weeks and discontinued if no meaningful improvement is observed. These agents are generally well tolerated, with injection-site reactions and gastrointestinal discomfort being most common adverse effects.
Gepants are a novel class of oral CGRP receptor antagonists that have emerged as effective options for
both acute and preventive migraine management. They offer an alternative for patients who cannot tolerate, or have contraindications to, triptans or parenteral CGRP antagonists. They have been shown to be effective in reducing monthly migraine days. Rimegepant can be used for the acute treatment of migraine to provide rapid relief of pain and associated symptoms, while it may also be taken on alternate days for prevention. Atogepant is licensed for once-daily dosing in preventive therapy. Gepants are generally well tolerated, with nausea and somnolence being the most common adverse effects. They represent a significant advancement in migraine therapy, bridging the gap between acute and preventive treatment approaches.
Lifestyle modifications are an important part of migraine prevention. Patients should be encouraged to maintain regular sleep patterns, consistent meals, adequate hydration and physical activity, and to identify potential triggers such as stress, odours, hormonal changes, caffeine excess and skipped meals. A headache diary can help recognise patterns and monitor treatment response. Relaxation training and cognitive behavioural therapy may be beneficial, particularly when stress is a contributing factor. Riboflavin 400mg once daily may help reduce migraine frequency and severity in some patients. Acupuncture may be considered if preventive therapy fails or is unsuitable. Intramuscular injections of botulinum toxin type A may also be considered for the prevention of chronic migraine in adults, if at least three preventive medicines have failed or are not tolerated.
Monitoring and review of preventive therapy are essential. Response to treatment should be assessed after eight- to-12 weeks, with a target of at least a 50 per cent reduction in migraine frequency or severity. If effective, treatment may be continued for six-to-12 months before considering gradual withdrawal. If a preventive option fails or is not tolerated, an alternative should be considered.
Role of the pharmacist
Pharmacists have a pivotal role in the multidisciplinary management of migraine, from patient education and medication safety to adherence support. Pharmacists are among the most accessible healthcare professionals and are often the first point of contact for patients seeking relief from migraine. They can help distinguish migraine from other headache types, ensuring that patients receive appropriate treatment and timely referral when necessary. Pharmacists contribute significantly to rational analgesic use, counselling patients on the safe and effective use of over-the-counter options such as ibuprofen, paracetamol and sumatriptan, now available without prescription in Ireland. This includes advising on correct dosing, duration of use and strategies to minimise the risk of medication overuse headache, as well as highlighting the importance of avoiding opioid-containing products in acute migraine management.
Patient education and lifestyle support are key components of pharmacist-led care. Pharmacists can advise on trigger management, maintaining regular sleep patterns, consistent meals, adequate hydration and the use of a headache diary to monitor triggers and treatment response. Reinforcing self-care empowers patients to take an active role in managing their symptoms and preventing attacks.
Pharmacists also play a key role in ensuring the safe and effective use of prescribed medications. This involves checking for potential drug interactions, monitoring for adverse effects and counselling patients on pregnancy precautions when using teratogenic medicines such as topiramate or sodium valproate. Reinforcing adherence is essential, as consistent dosing is critical for the success of preventive therapy. Pharmacists can also counsel on the correct storage, handling and administration of CGRP monoclonal antibodies and gepants, ensuring optimal therapeutic outcomes.
Through patient counselling, follow-up and collaboration with other healthcare professionals, pharmacists are integral to improving migraine outcomes, minimising medication-related harm and enhancing quality of life for patients.
References upon request
