Flunarizine

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Contents

[edit] BRAND NAMES

[edit] STRUCTURE

Flunarizine.JPG

[edit] MECHANISM OF ACTION

Flunarizine is a lipophilic diphenyl piperazine derivative. It is non selective voltage-dependent calcium channel blocker in smooth muscle and neuronal cells.

It is a fluorinated derivative of Cinnarizine, which is more potent and has a much longer half-life.

Flunarizine has the ability to cross the blood brain barrier , antagonise cellular calcium overload by reducing excessive transmembrane calcium influxes.

Flunarizine may therefore suppress hyperexcitability, produce antiepileptogenic activity and alter neurotransmitter actions.

Flunarizine proved to be as effective as topiramate in the treatment of chronic migraine [1]

Flunarizine is well absorbed from the gut, reaching peak plasma levels within 2 - 4 hours and reaching steady state at 5 - 6 weeks. After extensive hepatic metabolism, flunarizine and its metabolites are excreted through the faeces via the bile. The mean terminal elimination half-life is about 18 days. Plasma protein binding is 99%.

[edit] INDICATIONS

  • Prophylaxis of classic (with aura) or common (without aura) migraine.
  • Symptomatic treatment of vestibular vertigo (due to a diagnosed functional disorder of the vestibular system).

[edit] DOSAGE

Migraine Prophylaxis

  • Starting Dose: 10 mg at night in patients less than 65 years of age and 5 mg daily in patients older than 65 years. If, during this treatment depressive, extrapyramidal or other unacceptable symptoms occur, administration should be discontinued. If, after 2 months of this initial treatment, no significant improvement is observed, the patient should be considered a non-responder and administration should be discontinued.
  • Maintenance Treatment: If a patient is responding satisfactorily and if a maintenance treatment is needed, the dose should be decreased to 5 days treatment at the same daily dose with two successive medicine free days every week. Even if the prophylactic maintenance treatment is successful and well tolerated, it should be interrupted after 6 months and it should be re-initiated only if the patient relapses.


Vertigo The same dosage should be used as for migraine, but the starting treatment should not be given longer than needed for symptom control, which generally takes less than two months. After one month of treatment for chronic vertigo or after two months treatment for paroxysmal vertigo, no significant improvement is observed, the patient should be considered a non-responder and administration should be discontinued.

[edit] CONTRAINDICATIONS

  • Hypersensitivity to flunarizine.
  • Flunarizine is contra-indicated in patients with a history of depressive illness, or with pre-existing symptoms of Parkinson's disease or other extrapyramidal disorders.
  • Safety in pregnancy and lactation has not been established.

[edit] WARNINGS AND PRECAUTIONS

Flunarizine may lead to drowsiness which is aggravated by the simultaneous intake of alcohol or other central nervous system depressants.

Patients should be cautioned against driving motor vehicles or performing other potentially hazardous tasks where a loss of mental alertness may lead to accidents.

Flunarizine is not suited for aborting a migraine attack. The possible occurrence of an attack is therefore no reason to increase the dose of Flunarizine.

Flunarizine may give rise to extrapyramidal and depressive symptoms and reveal Parkinsonism, especially in predisposed patients such as the elderly. Flunarizine should therefore be used with caution in such patients.

[edit] INTERACTIONS

Galactorrhoea has been reported in few woman on oral contraceptives within the first two months of Flunarizine treatment.

Hepatic enzyme inducers such as carbamazepine and phenytoin may interact with flunarizine by increasing its metabolism. An increase in dosage of flunarizine may be required.

[edit] PREGNANCY AND LACTATION

[edit] SIDE EFFECTS

Drowsiness and/or fatigue, as well as weight gain and/or increased appetite may occur.

The following adverse experiences have been reported during chronic treatment with Flunarizine: depression, of which female patients with a history of depressive illness may be particularly at risk; extrapyramidal symptoms (such as bradykinesia, rigidity, akathisia, orofacial dyskinesia, tremor), of which elderly patients seem particularly at risk.

Infrequently reported adverse reaction are: heartburn; nausea; gastralgia; insomnia; anxiety; galactorrhoea; dry mouth; muscle ache; skin rash.

[edit] RELATED LINKS

[edit] BIBLIOGRAPHY

[edit] REFERENCES

  1. http://www.ncbi.nlm.nih.gov/pubmed/24081889
Vertigo
Betahistine   Cinnarizine   Dimenhydrinate/Cinnarizine   Flunarizine   Piracetam   Prochlorperazine
Antimigraine preparations
5 HT1 agonists (Triptans) Almotriptan (Almogran, Axert)   Eletriptan (Relpax)   Frovatriptan (Frova, Migard, Menatriptan)   Rizatriptan (Maxalt)   Sumatriptan (Imigran)   Zolmitriptan (Zomig)
Ergot alkaloids Dihydroergotamine   Ergotamine
NSAIDs/ Analgesics Indometacin   Acetylsalicylic acid (Aspirin)   Diclofenac (Voltaren)   Ibuprofen (Advil, Brufen, Dolgit, Nurofen)   Ketorolac (Toradol)   Naproxen (Naprosyn, Aleve)   Nimesulide   Paracetamol (Efferalgan, Panadol...)
Prophylaxis Cinnarizine (Stugeron, Stugeron forte)   Flunarizine (Sibelium)   Nifedipine (Adalat)   Pizotifen   Propranolol (Inderal)   Topiramate (Topamax)