Migraine Pregnancy: There are no adequate data on the developmental risk associated with use in pregnant women. In animal studies, adverse effects on development (increased incidences of fetal abnormalities, increased embryofetal and offspring mortality, decreased fetal body weight) occurred at maternal exposures less than (rabbit) or greater than (rat) those observed clinically. A US pregnancy exposure registry monitors outcomes in women exposed during pregnancy.

Lasmiditan

Brand names: Reyvow

Lasmiditan is a selective serotonin 5-HT1F receptor agonist (a ditan) used for the acute treatment of migraine with or without aura.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 50 mg, 100 mg, or 200 mg taken orally, as needed

Route: Oral — administer tablets whole; do not split, crush, or chew. May be taken with or without food.

Frequency: As needed for a migraine attack; no more than one dose should be taken in 24 hours

Max: One dose (maximum 200 mg) in any 24-hour period

SOURCE CAVEAT — no UK SPC posology was retrieved for lasmiditan; this is US FDA labelling (REYVOW, Eli Lilly, label date 2024-11-13) and the UK licensed dose must be confirmed against the UK SPC before publication. The US label states that a second dose has NOT been shown to be effective for the same migraine attack (note: this contradicts the repeat-dose wording currently on the site page — clinician to reconcile). REYVOW should not be taken unless the patient can wait at least 8 hours between dosing and driving or operating machinery. The safety of treating an average of more than 4 migraine attacks in a 30-day period has not been established. Available as 50 mg and 100 mg tablets (US). Paediatric use: safety and effectiveness in paediatric patients have not been established. Elderly (65 years and over): dizziness occurred more frequently (19% versus 14% in those under 65) and a larger increase in systolic blood pressure occurred; dose selection should be cautious, usually starting at the low end of the dosing range.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

None (the US label states 'CONTRAINDICATIONS: None')

Side effects

Dizziness (most common, >= 5% and greater than placebo)
Fatigue (most common, >= 5% and greater than placebo)
Paraesthesia (most common, >= 5% and greater than placebo)
Sedation (most common, >= 5% and greater than placebo)
Driving impairment and CNS depression — significant impairment demonstrated at 50 mg, 100 mg and 200 mg; more sleepiness at 8 hours post-dose than placebo
Serotonin syndrome — reactions consistent with serotonin syndrome reported; discontinue if symptoms occur

Interactions

Alcohol and other CNS depressants — concomitant use not evaluated in clinical studies; because of the potential for sedation and other cognitive/neuropsychiatric reactions, use with caution (US label)
Serotonergic drugs (SSRIs, SNRIs, TCAs, MAO inhibitors, trazodone), over-the-counter dextromethorphan and herbal supplements such as St John's Wort — may increase the risk of serotonin syndrome; use with caution (US label)
Heart-rate-lowering drugs — lasmiditan may further lower heart rate; in a drug interaction study a single 200 mg dose added to propranolol decreased heart rate by an additional 5 beats per minute (mean maximum 19 beats per minute) (US label)

Clinical monograph

How it works

It activates 5-HT1F receptors to inhibit trigeminal nociceptive signalling and neuropeptide release, relieving migraine without causing the vasoconstriction associated with triptans.

Prescribing in practice

It impairs the ability to drive, so patients must not drive or operate machinery for several hours after each dose owing to dizziness and sedation.
Because it crosses the blood-brain barrier and acts centrally, central nervous system effects such as somnolence and paraesthesia are common.
Caution and dose review are advised when combined with other serotonergic or CNS-depressant medicines.

Monitoring

No routine laboratory monitoring is required, but assess migraine response and central nervous system adverse effects clinically.

Counselling the patient

Do not drive or operate machinery for the period specified after taking a dose.
Avoid alcohol, which can worsen drowsiness.
Tell your clinician about all medicines that affect serotonin or cause sleepiness.

Evidence & guidelines

Lasmiditan is licensed for acute migraine on the basis of randomised trials showing pain freedom without the vascular contraindications of triptans.

Reference: SAMURAI trial NEJM 2019; 381(23):2230-2241; SPARTAN trial NEJM 2019; 381(23):2245-2256; MHRA SPC; EAN Migraine Guidelines 2022; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways