Betahistine exerts its therapeutic effects through multiple mechanisms:

1. Histamine H1 Receptor Agonism:
   • Stimulates H1 receptors in the inner ear, leading to vasodilation and improved microcirculation in the cochlea and vestibular system (BNF).
2. Histamine H3 Receptor Antagonism:
   • Blocks H3 receptors, increasing the release of endogenous histamine and further enhancing blood flow (Lippincott).
3. Reduction of Endolymphatic Pressure:
   • Improves fluid drainage in the endolymphatic sac, reducing pressure and alleviating symptoms like vertigo and tinnitus (Lange).
4. Central Vestibular Compensation:
   • Enhances the brain’s ability to adapt to vestibular imbalances, improving balance and reducing dizziness (Lippincott).

Betahistine is primarily indicated for:

1. Ménière’s Disease:
   • Reduces the frequency and severity of vertigo attacks.
   • Alleviates tinnitus and hearing loss associated with the condition.
2. Other Vestibular Disorders:
   • Used off-label for vertigo and dizziness caused by other inner ear conditions, such as vestibular neuritis or labyrinthitis.
3. Symptomatic Relief:
   • Improves balance and reduces nausea in patients with chronic vestibular dysfunction.

The dosage of betahistine varies depending on the condition being treated. Always follow the prescribing physician’s instructions.

Adults:

• Ménière’s Disease: 16–48 mg daily in divided doses (BNF).
  • Typical starting dose: 8 mg 3 times daily, adjusted based on response.

Elderly Patients:

• Use lower doses initially, as they may be more sensitive to side effects.

Administration Tips:

• Take with or after meals to minimize gastrointestinal side effects.
• Do not crush or chew the tablets; swallow them whole with water.

Betahistine is generally well-tolerated, but some patients may experience side effects:

Common:

• Gastrointestinal: Nausea, indigestion, bloating.
• Headache or dizziness.
• Mild skin rash or itching.

Rare but Serious:

• Severe allergic reactions (anaphylaxis).
• Worsening of asthma or peptic ulcer disease (due to histamine-like effects).

Before using betahistine, inform your healthcare provider if you have:

• A history of peptic ulcers or gastrointestinal bleeding.
• Asthma or other respiratory conditions.
• Pheochromocytoma (a rare adrenal gland tumor).
• Allergies to betahistine or any component of the formulation.

Special Populations:

• Pregnancy: Use only if benefits outweigh risks (BNF Category: Not formally established; caution advised).
• Breastfeeding: Limited data; avoid unless essential.
• Elderly Patients: Monitor for dizziness or gastrointestinal side effects.

Betahistine may interact with other medications, altering their effects:

1. Antihistamines:
   • May reduce the efficacy of betahistine by blocking H1 receptors.
2. Monoamine Oxidase Inhibitors (MAOIs):
   • Concurrent use may increase the risk of hypertensive crises.
3. Anticholinergics:
   • May counteract the vestibular benefits of betahistine.
4. Antihypertensives:
   • Betahistine’s vasodilatory effects may enhance blood pressure-lowering effects.

Generic Names in Pharmacy

• Betahistine dihydrochloride (active ingredient)

Common brand names: Betaserc®, Serc®, Vasomotal®