What is betahistine?

Betahistine: A Medication for Vestibular Disorders

Betahistine is a histamine analogue that acts as a weak H1 receptor agonist and more potent H3 receptor antagonist, primarily used in the treatment of vestibular disorders, particularly Ménière's disease, although recent high-quality evidence shows it is not more effective than placebo for reducing vertigo attacks. 1, 2

Mechanism of Action

• Betahistine works through histaminergic pathways, acting as a weak agonist for histamine H1 receptors and a strong antagonist for histamine H3 receptors 3, 4
• The medication's mechanism of action is believed to involve the central nervous system, particularly affecting neuronal systems involved in vestibular recovery after vestibular loss 4
• It may influence the histaminergic neurons of the tuberomamillary and vestibular nuclei 4

Clinical Applications

• Betahistine is primarily prescribed for Ménière's disease, especially during the intercritical phase to potentially reduce the number and severity of vertigo attacks 5
• It has been used in other vestibular disorders including:
  • Benign paroxysmal positional vertigo (BPPV) - to treat residual dizziness after successful treatment of otolithiasis 3
  • Vestibular neuritis - to potentially stimulate central compensation during vestibular rehabilitation 3
• The American Academy of Otolaryngology-Head and Neck Surgery does not routinely recommend betahistine for BPPV treatment 6

Efficacy Evidence

• The most recent high-quality evidence (BEMED trial) found no significant difference between betahistine (at both low 48 mg/day and high 144 mg/day doses) and placebo in reducing vertigo attacks in Ménière's disease patients over a 9-month treatment period 1, 2
• This finding contradicts earlier studies and meta-analyses that had suggested efficacy 1
• Some studies suggest betahistine may have a positive effect on hearing function in previously untreated Ménière's disease patients 7
• A modified-release formulation (48 mg once daily) has been shown to be non-inferior to standard betahistine (24 mg twice daily) in treating Ménière's disease and vestibular vertigo 8

Contraindications and Precautions

• Betahistine is completely contraindicated in patients with pheochromocytoma 1, 6
• It should be used with caution in patients with:
  • Asthma 1, 6
  • History of peptic ulcer disease 1, 6

Side Effects

• Common side effects include:
  • Headache 1, 8
  • Balance disorders 1
  • Nausea 1
  • Nasopharyngitis 1, 2
  • Feeling hot 1
  • Eye irritation 1
  • Palpitations 1
  • Upper gastrointestinal symptoms 1, 2

Clinical Considerations

• For acute vertigo attacks, medications with direct antiemetic and anti-vertigo effects like prochlorperazine are generally preferred over betahistine 2
• If betahistine is prescribed, patients should be reassessed regularly to evaluate improvement or stabilization of symptoms and monitor for side effects 1
• The optimal duration of treatment is unclear, with most studies covering only 2-12 weeks, though the BEMED trial covered a 9-month treatment period 1
• Betahistine is considered to have a low risk of major side effects 5

Common Pitfalls

• Continuing betahistine indefinitely without reassessing its effectiveness 2
• Expecting significant improvement in all symptoms of Ménière's disease, when evidence suggests limited efficacy for hearing loss, tinnitus, and ear fullness 5
• Failing to consider the most recent high-quality evidence (BEMED trial) which contradicts earlier positive findings about betahistine's efficacy 1
• Not recognizing that betahistine may be less effective during the acute phase of Ménière's disease and may need to be combined with other medications during acute attacks 5