Migraine: What It Is, What Triggers It & How Triptans Work

What is a migraine?

Migraine is a complex neurological condition characterised by recurrent, typically severe headache — usually unilateral and pulsating in quality — associated with nausea, vomiting, and marked sensitivity to light (photophobia) and sound (phonophobia). Attacks typically last between 4 and 72 hours and can be highly disabling.

NICE CKS distinguishes between migraine without aura (the most common type) and migraine with aura, in which neurological symptoms — most commonly visual disturbances such as flashing lights or zig-zag lines — precede or accompany the headache phase in around one-third of sufferers.

The Global Burden of Disease study ranks migraine as the second leading cause of disability worldwide, and the leading neurological cause of years lived with disability.

The four phases of a migraine

NICE CKS and the International Headache Society (IHS) describe up to four distinct phases that may occur during a migraine attack:

Common migraine triggers

NICE CKS notes that migraine triggers lower the threshold for attacks in susceptible individuals rather than directly causing them. The same trigger may not always provoke an attack, as neural sensitivity fluctuates. Commonly reported triggers include:

• Hormonal fluctuations — falling oestrogen levels, particularly around menstruation, are the most significant trigger in women. NICE CKS specifically identifies menstrual migraine as a clinical subtype requiring specific management consideration
• Sleep disruption — both insufficient and excessive sleep can trigger attacks
• Stress and post-stress relaxation — the "let-down" effect after a period of stress is a well-recognised precipitant
• Dehydration — one of the most consistently reported and modifiable triggers
• Skipping meals — irregular mealtimes and hypoglycaemia lower the migraine threshold
• Caffeine — both excessive intake and sudden withdrawal can trigger attacks
• Alcohol — particularly red wine; the mechanism may involve histamine and tyramine content
• Sensory stimuli — bright or flickering light, strong smells, and loud noise

Acute treatment: the NICE-recommended approach

NICE Guideline CG150 (Headaches in over 12s: diagnosis and management) sets out a clear evidence-based approach to acute migraine treatment:

1. First-line monotherapy: For people who prefer a single medication, NICE recommends an oral triptan, NSAID (e.g. ibuprofen, aspirin 900 mg), or paracetamol. NICE notes that aspirin 900 mg has good evidence for migraine, though it is less commonly used than triptans or NSAIDs
2. Combination therapy (NICE-preferred approach): NICE CG150 recommends offering an oral triptan combined with an NSAID or paracetamol for most adults, as combination therapy is more effective than monotherapy. An antiemetic (e.g. metoclopramide or domperidone) should be co-prescribed to manage nausea and improve gastric absorption of oral medications during an attack

Triptans: the gold standard

Triptans are 5-HT₁B/₁D receptor agonists that act by constricting dilated cranial blood vessels and inhibiting the release of inflammatory neuropeptides around the trigeminal nerve. NICE CG150 recommends triptans — alone or in combination with an NSAID or paracetamol — as the most effective pharmacological treatment for acute migraine in adults.

All triptans are Prescription Only Medicines (POMs) in the UK, with the exception of sumatriptan 50 mg, which is available as a Pharmacy (P) medicine for adults aged 18–65. Higher doses and other triptans require a prescription, available through Medicinex following a clinician-reviewed consultation.

Which triptan is available in the UK?

The BNF lists several triptans licensed in the UK for the acute treatment of migraine. NICE CG150 notes that if one triptan is not effective after an adequate trial, another should be tried — individual responses vary considerably.

Medication overuse headache

NICE CKS identifies medication overuse headache (MOH) — also called analgesic rebound headache — as one of the most important and commonly missed diagnoses in headache medicine. It occurs when acute headache medications are taken on 10 or more days per month for three consecutive months or more.

MOH affects all acute migraine treatments, including triptans, NSAIDs, paracetamol, and opioids. NICE CKS notes that it leads to a paradoxical increase in headache frequency and is a major driver of episodic migraine transforming into chronic migraine (15 or more headache days per month).

• Limit all acute migraine medications to a maximum of 2 days per week to avoid MOH
• If MOH is suspected, the overused medication should be gradually withdrawn with clinical support, as headache typically worsens initially before improving
• Patients with frequent attacks who are at risk of MOH should be assessed for preventive treatment

Keeping a migraine diary

NICE CKS recommends that all patients with recurrent headaches keep a prospective headache diary for a minimum of four weeks before any definitive management decisions are made. A well-kept diary enables clinicians and patients to:

• Confirm a migraine diagnosis and distinguish it from tension-type headache or other headache disorders
• Identify personal triggers that can be modified or avoided
• Monitor headache frequency to determine whether preventive treatment criteria are met (typically 4 or more migraine days per month)
• Assess response to acute treatment over time
• Detect early signs of medication overuse headache by tracking medication use days