Composition

• Betahistine 8 mg

Packing

• (20X15)(Alu-Alu)
  
  

MRP

• 155

Overview

Betahistine is a histamine analog and is mainly used to treat vertigo. It works by improving the blood flow in the inner ear which reduces the pressure of excess fluid there. Excess fluid can send signals to the brain causing nausea, dizziness or spinning sensations (symptoms of Ménière's disease). Betahistine additionally dampens down the nerve signals sent from the inner ear to the brain relieving the symptoms of Ménière's disease.

Indications

• Vertigo
• Ménière's disease
• Tinnitus

Mode of Action

Betahistine primarily acts as a histamine H1-agonist with 0.07 times the activity of histamine. Stimulating the H1-receptors in the inner ear causes a vasodilatory effect and increased permeability in the blood vessels which results in reduced endolymphatic pressure. Betahistine is believed to act by reducing the asymmetrical functioning of sensory vestibular organs as well as by increasing vestibulocochlear blood flow. Doing so aids in decreasing symptoms of vertigo and balance disorders.
Betahistine also acts as a histamine H3-receptor antagonist which causes an increased output of histamine from histaminergic nerve endings which can further increase the direct H1-agonist activity. Furthermore, H3-receptor antagonism increases the levels of neurotransmitters such as serotonin in the brainstem, which inhibits the activity of vestibular nuclei, helping to restore proper balance and decrease in vertigo symptoms.

Pharmacokinetics

When given orally, betahistine is rapidly absorbed from the gastrointestinal tract. Little or no binding occurs with human plasma proteins. Betahistine is metabolized primarily into 2-pyridylacetic acid and is subsequently excreted in the urine. Half-life of the drug is 3 to 4 hours.

Side Effects

Common side effects of the drug includes:

• Feeling sick (nausea)
• Indigestion
• Headache
• Allergic skin reactions such as itching and rash (Less common)

Precautions & Warning

• Caution is advised in the treatment of patients with peptic ulcer or a history of peptic ulceration, because of the occasional dyspepsia encountered in patients on betahistine.
• Caution is advised in patients with severe hypotension.
• Clinical intolerance to Betahistine may occur in bronchial asthma patients (see section 4.5 and 4.8) - These patients should therefore be monitored carefully during the treatment with betahistine.

Contraindication

Betahistine is contraindicated in patients with phaeochromocytoma. As betahistine is a synthetic analogue of histamine it may induce the release of catecholamines from the tumor resulting in severe hypertension.

Drug Interaction

• Inhibition of betahistine metabolism by drugs that inhibit monoamino-oxidase (MAO) including MAO subtype B (e.g. Selegiline)
• Interaction with ethanol, a compound containing pyrimethamine with dapsone and another of potentiation of betahistine with salbutamol.