Flunarizine
Flunarizine is a calcium channel blocker used to prevent migraine attacks (migraine prophylaxis) rather than treat an attack once it has started. Flunarizine is used for Migraine prophylaxis (prevention).
Also called: Flumig (Philippines)
Pronunciation: floo-NAR-i-zeen.
- Generic name
- flunarizine
- Brand names
- Sibelium
- Drug class
- Calcium channel blocker (used for migraine prophylaxis)
- Form
- Tablet (5 mg)
- Route
- Oral
- Legal status
- Prescription-only medicine in Ireland; not licensed in the United Kingdom. US FDA approval status could not be confirmed in this pass and should not be assumed either way.
Availability and supply rules vary by country
Trade names by country: India · Nepal
Australia: · Full directory
What flunarizine is and how it works
Flunarizine is a calcium channel blocker used to prevent migraine attacks (migraine prophylaxis) rather than treat an attack once it has started. (2)
It is taken once daily, usually at night, and is generally used for a limited period (up to about 6 months) rather than indefinitely. It has specific contraindications related to mood and movement disorders that must be checked before starting.
Mechanism of action: how flunarizine works
Flunarizine is a calcium channel blocker that reduces arterial and arteriolar smooth-muscle spasm; its exact mechanism in migraine prevention is not detailed in the source reviewed. (1)
What is Flunarizine used for?
Migraine prophylaxis (prevention)
Used to reduce the frequency of migraine attacks in adults. It is a preventive treatment, not a treatment for an attack already in progress. (2)
Before taking flunarizine
Do not take / not appropriate for
- Do not take flunarizine if you currently have depression, or if you have a history of recurrent depression. (all products) (2)
- Do not take flunarizine if you have Parkinson's disease or another condition causing tremor, stiffness, or slowed movement (an extrapyramidal disorder). (all products) (2)
Tell your clinician about
- Any personal or family history of depression.
- Any history of Parkinson's disease, tremor, or other movement disorder.
- Your age, since older adults are usually started on a lower dose.
- Pregnancy, plans for pregnancy, or breastfeeding.
- Every other medicine you take.
Flunarizine dosage and how to take it
- Take exactly as prescribed, usually once daily at night.
- Once your migraines respond to treatment, your prescriber may have you take 2 drug-free days each week.
- Treatment is generally limited to about 6 months; do not continue beyond this or restart after stopping without your prescriber's advice.
- Do not change your dose or stop taking flunarizine without talking to your prescriber first.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2)
Missed dose
If you forget a dose, do not take the missed dose. Wait and take your next dose at the usual time, then continue as normal. Do not take a double dose to make up for a missed one.
Overdose
If you, or anyone else, takes more flunarizine than directed, contact a doctor or local hospital immediately. (1)
Flunarizine side effects
Weight gain is a very commonly reported effect. Mood and movement-related effects need particular attention given this medicine's specific contraindications.
Weight gain
What to notice: A very commonly reported effect (affects more than 1 in 10 people).
What to do: Discuss with your prescriber if significant or concerning. (1)
Increased appetite, blocked or runny nose, feeling low or depressed, sleep problems or sleepiness, nausea, constipation, stomach ache or digestive problems, muscle aches, breast pain, menstrual irregularities, fatigue
What to notice: Common effects (affect fewer than 1 in 10 people).
What to do: Tell your prescriber if troublesome or persistent. (1)
Anxiety, restlessness, low energy, disorientation, palpitations, low blood pressure, dry mouth, excessive sweating, swelling of hands/legs/feet, low libido, or mild allergic-type skin reaction (rash, flushing, hives)
What to notice: Uncommon effects (affect fewer than 1 in 100 people).
What to do: Tell your prescriber if these occur, especially if persistent or bothersome. (1)
New low mood or movement symptoms
What to notice: New or worsening depression, or new tremor, stiffness, or slowed movement.
What to do: Contact your prescriber promptly; a clinician will decide whether flunarizine needs to be stopped. (1)
Tingling/numbness or tinnitus
What to notice: Tingling or numbness in the hands or feet, or buzzing/hissing/whistling/ringing in the ears.
What to do: Tell your prescriber as soon as possible; you may need medical treatment. (1)
Extrapyramidal (movement) symptoms
What to notice: Jerky movements, slowness, muscle stiffness or rigidity, trembling, or unusual twitching of the tongue, face, mouth, jaw, or throat.
What to do: Tell your prescriber as soon as possible; an additional medicine may be needed to manage this, and a clinician will decide whether flunarizine needs to be stopped. (1)
Severe allergic reaction
What to notice: Swelling of the face, lips, mouth, tongue, or throat, which may cause difficulty swallowing or breathing.
What to do: Seek emergency medical help immediately. (1)
Serious warnings
Depression or movement disorder developing during treatment — urgent
Symptoms: New or worsening low mood, or new tremor, muscle stiffness, or slowed movement.
Action: Contact your prescriber promptly. These are recognised risks of this medicine, particularly with longer use, and the prescriber will decide whether to continue or stop treatment. (1)
Severe allergic reaction — emergency
Symptoms: Swelling of the face, lips, mouth, tongue, or throat, which may cause difficulty swallowing or breathing.
Action: Seek emergency medical help immediately. (1)
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| Tranquillisers or sleep medicines (medicines for anxiety or to help you sleep) | May increase drowsiness when combined with flunarizine. | Tell your prescriber and pharmacist about all other medicines you take, including tranquillisers or sleep aids. (1) |
| Oral contraceptives | May cause secretion of breast milk during the first two months of flunarizine treatment. | Tell your prescriber if you are taking an oral contraceptive and notice this effect. (1) |
| Medicines to control high blood pressure | Your prescriber may need to adjust the dose of your blood-pressure medicine while you take flunarizine. | Tell your prescriber about all blood-pressure medicines you take. (1) |
| Alcohol | The combined effect of flunarizine and alcohol can increase drowsiness. | Avoid drinking alcohol while taking flunarizine. (1) |
Pregnancy, breastfeeding, kidney/liver function, age
Older adults
Adults 65 and older are usually started on a lower dose (5 mg daily) compared with younger adults (10 mg daily). (2)
Depression or movement disorder history
This medicine is not suitable if you currently have depression, have had recurrent depression, or have Parkinson's disease or another movement disorder. (2)
Pregnancy and breastfeeding
Flunarizine is not recommended during pregnancy; talk to your prescriber before use if you are pregnant or trying to become pregnant. Do not breastfeed while taking flunarizine, since small amounts pass into breast milk. (1)
Driving and using machines
Flunarizine can make you drowsy. Do not drive or use tools or machines if this happens. (1)
Monitoring
Before starting
- Confirm the migraine diagnosis and screen for current or past depression and for Parkinson's disease or other movement disorders.
- Confirm age, since dosing differs for adults under and over 65.
During treatment
- Watch for new or worsening low mood, tremor, or movement changes.
- Reassess after up to about 6 months of treatment; do not continue indefinitely without the prescriber's review.
Storage
Do not store above 25°C (77°F). Keep out of the sight and reach of children. Do not use after the expiry date printed on the packaging.
Study the drug class: Triptans and migraine agents (practice MCQs)
Professional information
Clinician-facing context only. Sourced from the Ireland-authorised HPRA/Janssen patient leaflet; verify against the current SmPC for exact prescribing detail.
Ireland
Indication: Migraine prophylaxis
Dose summary: Adults 18-64: 10 mg (two 5 mg tablets) once daily in the evening, after a meal. Adults 65+: 5 mg (one tablet) once daily in the evening. Not recommended in children. Maintenance with 2 consecutive drug-free days per week once responding. Maximum treatment duration approximately 6 months; complete break required, with restart to be decided by the prescriber if migraine relapses.
Renal context: Not established in the source reviewed for this dossier. (1)
Hepatic guidance
Not established in the source reviewed for this dossier.
Overdose note
The patient leaflet directs contacting a doctor or local hospital immediately for suspected overdose; no specific antidote or overdose-management detail is given in this source. (1)
Frequently asked questions
What is flunarizine used for?
flunarizine is prescribed for approved indications. Always follow your healthcare provider's guidance.
What are the side effects of flunarizine?
Common side effects may include gastrointestinal symptoms and headache. Serious side effects require immediate medical attention.
Can I take flunarizine with other medications?
Always inform your healthcare provider about all medications you are taking, including over-the-counter products and supplements.
What is the mechanism of action of flunarizine?
Flunarizine is a calcium channel blocker that reduces arterial and arteriolar smooth-muscle spasm; its exact mechanism in migraine prevention is not detailed in the source reviewed. (1)
References
- Sibelium 5 mg Tablets (flunarizine) — Package Leaflet: Information for the UserHealth Products Regulatory Authority (HPRA), Ireland — Patient Information Leaflet, Marketing Authorisation Holder Janssen Sciences Ireland UC (manufactured by Janssen-Cilag S.p.A., Italy) · Ireland · accessed 2026-07-26 · source 1
- Migraine prophylaxis: flunarizine -- Evidence summary (ESUOM33)National Institute for Health and Care Excellence (NICE), United Kingdom -- via web search summary; direct page fetch returned HTTP 403, not independently verified as full text · United Kingdom / Ireland · accessed 2026-07-26 · source 2
- flunarizine — RxNorm normalized drug concept (RXCUI 4459)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 3
Brand names by country
Single-ingredient flunarizine names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.
Priority countries
India
Source-listed products; local stock and regulatory approval have not been confirmed. Check the exact ingredient, strength, and formulation with a pharmacist.
- Sibelium 10mg TabletTablet · 10mg · Janssen Pharmaceuticalspharmacy source · checked 2026-09-24
- Migrafin 10 TabletTablet · 10mg · Leeford Healthcare Ltdpharmacy source · checked 2026-09-24
- Flunarin 10 TabletTablet · 10mg · FDC Ltdpharmacy source · checked 2026-09-24
- Migranex 10 TabletTablet · 10mg · Intas Pharmaceuticals Ltdpharmacy source · checked 2026-09-24
- Zerograin 10 TabletTablet · 10mg · Mankind Pharma Ltdpharmacy source · checked 2026-09-24
- Fluner 10 TabletTablet · 10mg · Geno Pharmaceuticals Ltdpharmacy source · checked 2026-09-24
- Migon TabletTablet · 10mg · Cadila Pharmaceuticals Ltdpharmacy source · checked 2026-09-24
- Grenil-F 10 TabletTablet · 10mg · Karnataka Antibiotics & Pharmaceuticals Ltdpharmacy source · checked 2026-09-24
Nepal
Source-listed products; local stock and regulatory approval have not been confirmed. Check the exact ingredient, strength, and formulation with a pharmacist.
- Ciziron 10Tablet · 10mg · Panas Pharmaceutical Pvt. Ltd.reference source · checked 2026-09-24
- Efzin 10Tablet · 10mg · Asian Pharmaceuticals Pvt. Ltd.reference source · checked 2026-09-24
- Flugran 10Tablet · 10mg · Nepal Pharmaceuticals Pvt. Ltd.reference source · checked 2026-09-24
- FlunarinTablet · 10 mg · FDC Pharmaceutical Pvt. Ltd.reference source · checked 2026-09-24
- FlunerTablet · 5mg · Geno Pharmaceuticals Ltd.reference source · checked 2026-09-24
- FluriumTablet · 10mg · Beximco Pharmaceuticals Ltd.reference source · checked 2026-09-24
- Grane 10Tablet · 10mg · Sumy Pharmaceuticals Pvt. Ltd.reference source · checked 2026-09-24
- MigonTablet · 10mg · Cadila Pharmaceuticals Limited.reference source · checked 2026-09-24
View brands in additional countries.
Philippines
Flumig