Flunarizin

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Flunarizin

Method of action: Other Nervous System Drugs

Treatment option:

Medically reviewed

Marina Burgos

Last updated on 10/01/2026

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Flunarizin

What is Flunarizine?

Flunarizine is a medicinal compound classified as a selective calcium entry blocker. It belongs to a group of medications known as calcium antagonists, specifically the non-selective subclass that includes diphenylmethylamine derivatives. Unlike some other calcium channel blockers used primarily for cardiovascular conditions, flunarizine has a high affinity for brain tissue and is characterized by its long half-life.

Mechanism of Action

The primary function of flunarizine involves the inhibition of calcium overload in cells. It works by preventing the excessive entry of calcium ions across cell membranes. By stabilizing cellular activity in this manner, it protects cells from the damaging effects associated with calcium toxicity. Additionally, flunarizine exhibits properties that affect antihistaminic and sedative pathways, contributing to its overall pharmacological profile.

Primary Uses

Flunarizine is utilized in various therapeutic contexts, primarily focusing on neurological and vestibular conditions:

  • Prophylaxis of Migraine: It is used as a preventive measure to reduce the frequency and severity of migraine attacks in patients who experience frequent episodes.
  • Treatment of Vertigo: It is employed to manage symptoms of vestibular disorders, such as dizziness and vertigo, resulting from functional disorders of the inner ear.
  • Adjunctive Therapy: In some instances, it has been studied as an add-on treatment for refractory epilepsy, although this is less common than its use in migraine prevention.

Clinical Characteristics

Flunarizine is absorbed through the gastrointestinal tract and reaches peak plasma concentrations within a few hours. Due to its lipophilic nature, it distributes widely throughout the body's tissues. One of its most notable characteristics is its slow elimination rate, which allows for consistent levels of the medication in the system over time.

What side effects are possible with Flunarizin?

Possible Side Effects and Safety Information

The following safety information and adverse reactions are based strictly on official regulatory documents, such as the European Summary of Product Characteristics (SmPC) and other government product monographs.

Frequency-Classified Adverse Reactions

Adverse reactions are classified by their documented frequency of occurrence:

  • Very Common (Affects 1 in 10 or more individuals): Weight increased.
  • Common (Affects 1 to 10 in 100 individuals): Somnolence (drowsiness), Depression, Increased appetite, Rhinitis, Myalgia (muscle pain), Menstruation irregularities, and Fatigue.
  • Uncommon (Affects 1 to 10 in 1,000 individuals): Insomnia (difficulty sleeping), Extrapyramidal Disorder, and Galactorrhea (abnormal breast milk secretion).

Serious Adverse Reactions and System-Organ Effects

The regulatory labeling specifically highlights clinically significant adverse effects that primarily involve the Nervous System and Psychiatric systems:

  • Nervous and Psychiatric Systems: The label warns of the potential for serious adverse reactions, including the development of Extrapyramidal Symptoms (such as Parkinsonism and tardive dyskinesia) and the onset of Depressive Symptoms.
  • Time-Related Pattern: Monitoring for these extrapyramidal and depressive symptoms is particularly advised during maintenance treatment.

Official Safety Restrictions and Special Populations

Safety is defined by specific restrictions and considerations for at-risk groups:

  • Contraindications: Flunarizin is officially restricted from use in individuals with a history of Depressive Illness or pre-existing Parkinson’s Disease or other Extrapyramidal Disorders.
  • Special Population Risk: Elderly patients are officially documented to be at a higher risk for developing extrapyramidal and depressive symptoms.
  • Safety-Related Interaction: The use of Flunarizin with central nervous system depressants, such as alcohol or tranquillizers, may lead to excessive sedation.

Overdose and Emergency Response

Overdose and When to Seek Help

Official regulatory information describes flunarizin overdose based on reported cases of acute, high-dose ingestion.

Documented Overdose Manifestations

The following effects have been documented in cases of flunarizin overdosage:

  • Central Nervous System (CNS) Effects: Sedation, confusion, and agitation.
  • Cardiovascular Effects: Tachycardia (rapid heartbeat).

Based on the established pharmacological properties of the medication, general sedation and asthenia (fatigue/weakness) are also anticipated following exposures that substantially exceed the maximum recommended dose.

Required Emergency Actions

Any suspected or actual overdose of flunarizin requires immediate emergency medical attention. The patient must be transported to an emergency care facility for assessment and management.

Overdose Management Procedures

Treatment for acute overdosage is primarily symptomatic and supportive. Regulatory labeling notes that:

  • No specific antidote for flunarizin overdose is known.
  • Administration of activated charcoal may be considered, if appropriate, by the treating healthcare professional to aid in decontamination.

Healthcare professionals will manage the patient's symptoms and support vital functions until the drug is eliminated from the body.

Therapeutic Uses of Flunarizin

Flunarizine is commonly used to help patients manage symptoms associated with certain neurological and vestibular conditions. The primary therapeutic domains include the prophylaxis of frequent migraine and the management of vertigo and vestibular disorders.


Prophylaxis for Frequent and Severe Migraine

This medication is primarily used to offer preventive support for patients experiencing recurrent, severe episodes of throbbing head pain. Its application is centered on supporting the management of recurrent head pain patterns, which contributes to improved day-to-day comfort and assists with maintaining functional stability for those affected by chronic migraine.

“This medication is considered relevant in clinical settings involving recurrent or persistent sensations of spinning (vertigo), unsteadiness, or chronic dizziness.”

Supportive Management for Vestibular Symptoms

Flunarizine is applied in contexts where additional support for long-term symptomatic stabilization of the balance pathways is needed, helping to ease the overall burden of these disruptive episodes that interfere with daily functioning. The drug may be part of a management strategy for specific, challenging neurological conditions, such as certain forms of epilepsy that are resistant to conventional treatments, assisting in easing the impact of symptoms related to heightened physiological activity when symptoms prove difficult to manage.


Quick Fact: Support for Recurrent Head Pain Flunarizine is commonly used to help manage the overall symptom load for conditions characterized by episodic or fluctuating manifestations, often applied during phases when symptoms become more noticeable.

Regulatory References

  1. Summary of Product Characteristics (SPC) from the Health Products Regulatory Authority (HPRA) of Ireland, a key EU member state regulator

Eligibility and Restrictions for Use

The eligibility for Flunarizin is strictly governed by regulatory documentation, which outlines specific age groups and contraindications. The medicine is primarily indicated for use in adults 18 years of age and older.

Contraindicated Populations

Flunarizin is contraindicated in patients with a current depressive illness or a history of recurrent depression, and in patients with pre-existing Parkinson's Disease or other extrapyramidal disorders. Patients with known hypersensitivity to the drug or its excipients must not use it.

Age and Physiological Status Restrictions

  • Pediatric Use: Use is not recommended in children, infants, or neonates, as safety and efficacy have not been established in patients under 18 years of age.
  • Older Adults: Use requires caution in the elderly (65 years and older) due to an increased risk of extrapyramidal and depressive symptoms, often necessitating a lower initial dose.
  • Pregnancy and Lactation: As a precautionary measure, use should be avoided during pregnancy due to limited human data. Use during lactation is also generally advised against. Use with caution is noted for patients with impaired hepatic function.

These rules define the mandatory boundaries for the medicine’s use as established by government health authorities.

What should I know about interactions with other medicines?

The interaction profile of Flunarizine is defined by officially documented pharmacokinetic (PK) and pharmacodynamic (PD) effects when co-administered with specific medicinal products or substances. This information is based strictly on regulatory labeling.


Interaction-Related Constraints

  • Contraindicated Combination: Co-administration with Monoamine Oxidase Inhibitors (MAOIs) is a documented restriction that must be avoided due to the potential for severe, adverse effects on central nervous system function and blood pressure regulation.
  • Contraceptive Constraint: Flunarizine may officially reduce the efficacy of Oral Hormonal Contraceptives. Women initiating treatment or undergoing a dose escalation are required to use a non-oral barrier method of contraception for four weeks following that specific change in therapy.

Pharmacodynamic and Exposure Patterns

  • Additive Sedation Risk: Concomitant use with other CNS Depressants (including Alcohol and various sedating drugs) results in a pharmacodynamic interaction that significantly enhances drowsiness and sedation. This additive effect is formally noted in product labeling.
  • Reduced Drug Exposure: Hepatic Enzyme Inducers (such as Carbamazepine or Phenytoin) initiate a PK interaction by increasing Flunarizine's metabolism and clearance. This interaction leads to consistently lower Flunarizine plasma concentrations.
  • Cardiovascular Effects: Co-administration with Beta-blockers or other Calcium Channel Blockers may potentiate hypotensive effects. An additional caution is noted for use with medications that prolong the QT interval due to potential additive risk.

Mechanism of Action

Modulation of Cellular Excitability via Calcium Blockade

Flunarizine's primary action involves its role as a selective calcium entry blocker, specifically targeting neuronal T-type and vascular L-type calcium channels. By impeding the excessive influx of calcium ions (Ca^2+), the drug affects the neuronal membrane potential and induces vascular smooth muscle relaxation. This mechanism influences neurovascular hyper-reactivity and inhibits the propagation of large-scale electrical phenomena like Cortical Spreading Depression (CSD).


Involvement in Histaminergic and Neuropeptide Modulation

In addition to calcium channel activity, Flunarizine modulates the histaminergic system through H1-receptor antagonism, which reduces the amplitude of overactive signaling within the vestibular sensory pathways. The reduction in intracellular Ca^2+ also limits the release of vasoactive neuropeptides like CGRP (Calcitonin Gene-Related Peptide), thereby contributing to the modulation of activity within the neurovascular unit and attenuating neurogenic hyper-responsiveness.

Dosage and Administration Information

How to Use Flunarizine

Flunarizine is administered through the oral route, typically available as a tablet or capsule in 5 mg and 10 mg strengths. The medicine is intended for prophylactic use (prevention) and is not used to treat acute episodes. Administration follows a structured, once-daily schedule, often taken at night to align with established usage protocols.

Dosage Administration Rules

The standard approach to Flunarizine use involves dose differentiation based on age and a cyclic duration pattern. It may be taken with or without food.

Population Group Labeled Starting Dose Frequency & Timing
Adults (18 to < 65 years) 10 mg daily Once daily, often at bedtime
Older Adults (≥ 65 years) 5 mg daily Once daily, often at bedtime

Treatment must adhere to specific duration protocols. An initial assessment period of 2 months is typically used to determine patient response; administration is discontinued if no satisfactory improvement is noted. For patients who respond successfully, the maintenance phase should be limited and is generally interrupted after 6 months. Furthermore, the maintenance schedule may involve an intermittent pattern, such as two consecutive drug-free days per week. If a dose is missed, the standard procedure is to skip the missed dose and continue with the next scheduled dose; the dose should not be doubled. Use in children and adolescents under 18 years is generally not recommended due to insufficient data.

Recent Clinical Evidence

Research evidence / Overview of studies for Flunarizin

Evidence for Use in Migraine Prevention

Flunarizine was studied for its use in adults with frequent migraine, primarily through Randomized Controlled Trials (RCTs) against placebo and other preventive medicines. Research examined outcomes related to monthly migraine frequency and headache intensity over short-term periods, typically lasting three to four months. Studies reported measurements of a pattern of reduced monthly migraine frequency in flunarizine groups compared to placebo. Research examining flunarizine against some other preventive medicines found that the patterns of measured outcomes differed in certain aspects.

Evidence for Use in Vestibular Disorders and Vertigo

The evidence base includes RCTs and reviews where flunarizine was evaluated in adults with conditions marked by functional limitations due to vertigo. Studies monitored changes in the frequency and intensity of vertiginous episodes, often over approximately three months. Studies report how symptoms evolved in the observed populations, though research indicates that findings were mixed across different studies, partly due to the variety of causes for vertigo included in the research. Sample sizes were modest in some key controlled trials.

Evidence for Use in Treatment-Resistant Epilepsy

Research has explored flunarizine as an add-on therapy in small, specialized groups of children and adolescents with epilepsy resistant to other medications. These are often exploratory, open-label studies that measure changes in seizure frequency over short intervals. The evidence is limited and the certainty remains low for this application, as the results apply only to the populations studied and not the general epilepsy population.

Research Gaps and Uncertainty

The long-term data is limited regarding the sustained consistency of observations beyond the typical trial duration, meaning long-term effects are not fully established. Research concerning children and adolescents with migraine is based on smaller, older trials where evidence quality varies across studies. The data highlights what is known, and what is still uncertain, across all studied conditions.

Key Studies & References

  1. Summary of Product Characteristics - Sibelium 5 mg Tablets (Flunarizine Dihydrochloride) - HPRA
  2. Flunarizine Hydrochloride Capsules, 5 mg, oral Selective Calcium-Entry Blocker - Product Monograph (Health Canada)

Frequently Asked Questions (FAQ)

Common questions about Flunarizin (FAQ)


Q: How is Flunarizin different from other common migraine medicines?

Flunarizin is officially described as a selective calcium entry blocker which means it works by regulating the flow of calcium into certain cells. Its classification as a calcium channel blocker helps distinguish it from other groups of migraine preventive medicines, such as beta-blockers or anti-epileptic drugs, which have different primary mechanisms.


Q: Is it normal to feel tired when first starting Flunarizin?

Official documentation notes that tiredness and drowsiness (somnolence) are listed as a Common side effect. Regulatory documents advise patients to notify their healthcare professional if they start to feel tired, as a reduction or discontinuation of the dose may be required based on clinical assessment.


Q: Are there any long-term side effects associated with Flunarizin use?

Official warnings note that certain serious effects, such as extrapyramidal symptoms (which affect movement and coordination) and depressive symptoms, are risks, particularly during maintenance treatment or in older patients. Regulatory documents also note that weight gain is a Very Common side effect.


Q: Can Flunarizin cause changes in blood pressure?

The drug is officially noted to sometimes cause low blood pressure (hypotension) as an Uncommon adverse effect. Furthermore, official labeling advises caution because taking Flunarizin with other blood pressure medicines may potentiate (increase) those hypotensive effects.


Q: Why is Flunarizin sometimes prescribed for dizziness or vertigo?

Regulatory documents indicate Flunarizin is used for the treatment of vertigo that results from vestibular disorders. This use is based on its known actions, which include stabilizing the neuro-receptors in the vestibular (inner ear) sensory pathways.


Q: Can Flunarizin be taken during pregnancy?

Official documentation advises that use during pregnancy should be avoided as a precautionary measure due to a lack of sufficient human data. Use is generally considered only when the expected benefits are determined to outweigh the potential risks.


Q: Is Flunarizin a first-line treatment for migraine prevention?

Official indications often describe Flunarizin as an option for patients with frequent and severe migraine who have not responded satisfactorily to other treatments or who experienced unacceptable side effects with other therapy. This descriptive language indicates its consideration for use in those who have not responded to, or tolerated, other available therapies.


Q: Does Flunarizin help with tension headaches?

The official indication for Flunarizin is strictly limited to the prophylaxis of migraine and the treatment of vertigo. It is not officially labeled or approved for the treatment of tension headaches.


Q: What is the difference between Flunarizin and Cinnarizine?

Both medicines are derivatives of piperazine and function as calcium entry blockers. A key difference noted in scientific reviews is that Flunarizin has a longer half-life than Cinnarizine. This characteristic supports a once-daily dosing schedule, whereas Cinnarizine may require more frequent administration.


Q: Is it safe to drink alcohol while taking Flunarizin?

Official documents describe a known interaction with alcohol, stating that combining the two will enhance drowsiness and sedation. Official labeling advises that because co-administration will enhance drowsiness and sedation, patients are warned to avoid consuming alcohol while taking this medicine due to the additive effect on the central nervous system.


Q: Is there a risk of withdrawal symptoms when stopping Flunarizin?

The regulatory documents do not specifically list 'withdrawal symptoms' as an adverse reaction. However, the official documentation details a structured process for discontinuation (discontinuing after 2 months or interrupting after 6 months).


Q: How quickly do the side effects of Flunarizin usually go away after stopping?

Official information and case reports concerning serious adverse effects, such as extrapyramidal symptoms, suggest that symptoms typically improve or resolve over a variable period of time after the drug is stopped. The time required for resolution is variable.


Q: Can Flunarizin cause problems with motor skills or coordination?

Official warnings specifically note the potential for extrapyramidal symptoms, which include movement disorders such as slowness, muscle stiffness, tremor, and restlessness. These conditions directly affect a person's motor skills and coordination, and the labeling advises that monitoring for these symptoms is necessary.


Q: Are there any required tests before starting Flunarizin?

Official regulatory information advises that patients should be assessed at regular intervals for the potential development of depressive or extrapyramidal symptoms. While no specific pre-treatment laboratory tests (like blood work) are consistently noted as mandatory in product monographs, regular monitoring during treatment is a defined requirement.


Q: Can Flunarizin be taken with other Calcium Channel Blockers?

Official product information advises caution when using Flunarizin with other calcium channel blockers or beta-blockers. The risk is that this combination may potentiate hypotensive effects (increase the likelihood of low blood pressure). For this reason, close monitoring of blood pressure may be required when using this combination.


Q: Is there a generic version of Flunarizin available?

Flunarizin is the active ingredient (INN) found in various brand-name products. In many markets where the medicine is authorized, both the brand name and generic versions of the tablets or capsules are available to patients.


Q: Can Flunarizin be taken with herbal supplements?

Regulatory documents advise patients to inform their healthcare professional about all medicines they take, including all herbal products or natural supplements. For many supplements, specific interaction data with Flunarizin is not established, which requires caution and careful review.


Q: Why are people often told to monitor for changes in mood while on Flunarizin?

Monitoring for mood changes is required because Depression is listed as a Common side effect and a history of depressive illness is an official contraindication for using the drug.

How should Flunarizin be stored and disposed of?

How to Store and Dispose of Flunarizine

Official regulatory guidelines strictly define the conditions necessary to maintain the integrity and safety of Flunarizine tablets or capsules.


Storage Requirements

Flunarizine must be stored at a temperature not exceeding 30 C (86 F) and should not be frozen. The product requires protection from moisture and light. To ensure stability, the medication must be kept in its original container and the container must be tightly closed.

Child Safety and Disposal

It is mandatory to keep the medicine out of the sight and reach of children. Unused or expired Flunarizine should not be disposed of via wastewater or household trash. Disposal must occur at an authorized drug take-back point or by following specific instructions from local waste authorities.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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