overview on betahistine as a treatment for vertigo

1. What is vertigo?
Vertigo is condition in which you feel dizzy and off-balanceor you feel like the
objects around you are moving when they are not.
What is betahistine ?
Betahistine -dihydrochloride (brand names Veserc, Serc, Hiserk, Betaserc,
Vergo) is an anti-vertigo drug. It is commonly prescribed for balance disorders
or to alleviate vertigo symptoms associated with Ménière's disease.
Mechanism of action:
Betahistine has a very strong affinity as an antagonist for histamine H3 receptors
and a weak affinity as an agonist for histamine H1 receptors .
Betahistine has two mechanisms of action.
Primarily, it a full agonist on the H1 receptors located on blood vessels in the
inner ear. This gives rise to local vasodilation and increased permeability, which
helps to reverse the underlying problem of endolymphatic hydrops.
More importantly, betahistine has a powerful antagonistic effects at H3
receptors, thereby increasing the levels of neurotransmitters histamine,
acetylcholine, norepinephrine, serotonin, and GABA released from the nerve
endings.

2. The increased amounts of histamine released from histaminergic nerve endings
can stimulate receptors. This stimulation explains the potent vasodilatory effects
of betahistine in the inner ear, that are well documented.
Betahistine seems to dilate the blood vessels within the inner ear which can
relieve pressure from excess fluid and act on the smoothmuscle.
It is postulated that betahistine's increase in the level of serotonin in the
brainstem inhibits the activity of vestibular nuclei.
How to use :
Dosage forms include:
 Betaserc 8 mg,
 Betaserc 16 mg
 and Betaserc 24 mg.
The usual initial doseis 8 mg of Betaserc three times a day. Dosage may
be increased to a maximum of 48 mg per day, until the proper effect is
achieved.
It should be avoided in children under the age of 18.

3. Precautions:
This medicine should be avoided in the following conditions:
 In patients allergic to the active substancebetahistine or other
similar medicines
 In patients who have adrenal gland tumor (pheochromocytoma)
It should be used only with extra precautions in patients with asthma and
in patients with gastricor duodenal ulcer.
Interactions:
Betaserc should be avoided in combination with the following medicines:
 Medicines used in the treatment of psychiatric disorders, the so-
called MAO inhibitors (monoamineoxidase inhibitors), such as:
o moclobemide,
o selegiline,
o isocarboxazid,
o phenelzine and others.
As the drug has antagonistic effect on H3 receptors causing an increase of
acetylcholine, norepinephrine & serotonin where MOA- inhibitors inhibit
the enzyme responsible for these neurotransmitters breakdown leading to
extra increase of there levels (pharmacodynamic addition)
 Antihistamines, medicines used in the treatment of allergy, such as:
o dimenhydrinate,
o diphenhydramine,
o cinnarizine,
o cetirizine and others.
Side effects:
1. nausea,
2. vomiting,
3. dyspepsia,
4. abdominal pain,
5. flatulence,
6. headache,
7. hypotension (low blood pressure),

4. 8. orthostatic hypotension (a sudden drop in blood pressure that
occur when you stand up from a sitting or lying position),
9. allergy and others.
References:
https://pharmacybook.net
 Sokolova L, Hoerr R, Mishchenko T (2014). "Treatment of Vertigo: A Randomized,
Double-Blind Trial Comparing Efficacy and Safety of Ginkgo biloba Extract EGb 761
and Betahistine". Int J Otolaryngol. 2014: 682439. PMC 4099171 .
PMID 25057270. doi:10.1155/2014/682439.
 Botta L, Mira E, Valli S, Zucca G, Perin P, Benvenuti C, Fossati A, Valli P (June
2001). "Effects of betahistine and of its metabolites on vestibular sensory organs.".
Acta Otorhinolaryngol Ital. 21 (3 Suppl 66): 24–30. PMID 11677836.
Prepared by :
Ph. Abeer abd el rahman
B.SC of pharmacy
Thank you 