Consumer medicine information


Betahistine dihydrochloride


Brand name

Serc Tablets

Active ingredient

Betahistine dihydrochloride




Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using Serc.

What is in this leaflet

This leaflet answers some common questions about Serc.

It does not contain all the available information. It does not take the place of talking to your doctor or pharmacist.

All medicines have risks and benefits. Your doctor or pharmacist has weighed the risks of you taking this medicine against the benefits they expect it will have for you.

If you have any concerns about taking this medicine, ask your doctor or pharmacist.

Keep this leaflet with the medicine.

You may need to read it again.

What Serc is used for

Serc is used to treat a disorder of your inner ear. This disorder may include one or more of the following symptoms, in one or both ears:

  • ringing in the ears (tinnitus)
  • loss of clear hearing
  • problems with balance (vertigo)

These symptoms may also be associated with nausea, vomiting and headache. Often these symptoms together are referred to as Meniere's Syndrome.

Serc tablets contain the active ingredient betahistine dihydrochloride. Serc works by improving the blood flow of the inner ear and restoring it to normal. It also acts on the nerve endings in the inner ear to normalise the way in which the nerves respond to outside influences.

Ask your doctor if you have any questions about why it has been prescribed for you.

Your doctor may have prescribed it for another purpose.

This medicine is not addictive.

This medicine is available only with a doctor's prescription.

Before you take Serc

When you must not take it

Do not take Serc if you have an allergy to:

  • any medicine containing betahistine dihydrochloride
  • any of the ingredients listed at the end of this leaflet

Some symptoms of an allergic reaction include skin rash, itching, shortness of breath or swelling of the face, lips or tongue, which may cause difficulty in swallowing or breathing.

Do not take this medicine if you are pregnant.

It may affect your developing baby if you take it during pregnancy.

Do not breastfeed if you are taking this medicine.

The active ingredient in Serc may pass into breast milk and therefore there is a possibility your baby may be affected.

Do not give Serc to a child under the age of 18 years.

Do not take this medicine if you a rare abnormality of the adrenal gland known as phaeochromocytoma.

Do not take this medicine if you have or have had a peptic ulcer.

Do not take it after the expiry date printed on the pack or if the packaging is damaged or shows signs of tampering.

If it has expired or is damaged return it to your pharmacist for disposal.

Before you start to take it

Tell your doctor if you have any allergies to any other medicines, foods, preservatives or dyes.

Tell your doctor if you have or have had any of the following medical conditions:

  • a peptic ulcer
  • asthma
  • a history of allergic skin conditions

Tell your doctor if you are pregnant, intend to become pregnant. or are breastfeeding

Your doctor can discuss the risks and benefits involved.

If you have not told your doctor about any of the above, tell them before you take Serc.

Taking other medicines

Tell your doctor or pharmacist if you are taking any other medicines, including any that you buy without a prescription from your pharmacy, supermarket or health food store.

Some medicines and Serc may interfere with each other. These include:

  • any anti-histamine medications, which are used to treat allergies and allergic reactions

These medicines may be affected by Serc, or may affect how well it works. You may need to use different amounts of your medicine, or take different medicines.

Your doctor or pharmacist has more information on medicines to be careful with or to avoid while taking Serc.

How to take Serc

Follow all directions given to you by your doctor or pharmacist carefully.

They may differ from the information contained in this leaflet.

If you do not understand the instructions on the box, ask your doctor or pharmacist for help.

How much to take

The usual adult starting dose is half to one tablet taken three times a day. However your doctor may prescribe a different dose depending on the severity of your condition.

How to take it

Swallow the tablet whole with a full glass of water.

When to take it

Take Serc at about the same time each day.

Taking it at the same time each day will have the best effect. It will also help you remember when to take it.

Take Serc during or immediately after a meal.

If you take Serc on an empty stomach, it may cause stomach upsets.

How long to take it

Continue taking your medicine for as long as your doctor tells you.

If you follow your doctor's instructions Serc should start working within a few days, although in some cases it may take a few weeks. The length of time that you should take Serc tablets varies from patient to patient. Some patients respond rapidly to treatment and others may take some time. Please be patient with your treatment and take your tablets regularly.

If you forget to take it

If it is almost time for your next dose, skip the dose you missed and take your next dose when you are meant to.

Otherwise, take it as soon as you remember, and then go back to taking your medicine as you would normally.

Do not take a double dose to make up for the dose that you missed.

This may increase the chance of getting an unwanted side effect.

If you are not sure what to do, ask your doctor or pharmacist.

If you have trouble remembering when to take your medicine, ask your pharmacist for advice.

If you take too much (overdose)

Immediately telephone your doctor, or the Poisons Information Centre (13 11 26), or go to Accident and Emergency at your nearest hospital, if you think you or anyone else may have taken too much Serc. Do this even if there are no signs of discomfort or poisoning.

Symptoms of an overdose may include nausea.

While you are using Serc

Things you must do

If you are about to be started on any new medicine, remind your doctor and pharmacist that you are taking Serc.

Tell any other doctors, dentists and pharmacists who treat you that you are taking this medicine.

If you are going to have surgery, tell the surgeon that you are taking this medicine.

If you become pregnant while you are taking this medicine, tell your doctor or pharmacist immediately.

Things you must not do

Do not use this medicine to treat any other complaints unless your doctor or pharmacist tells you to.

Do not give this medicine to anyone else, even if they have the same condition as you.

Do not stop taking Serc, or change the dosage, without checking with your doctor.

Side effects

Tell your doctor or pharmacist as soon as possible if you do not feel well while you are taking Serc.

It helps most people, but it may have unwanted side effects in a few people. All medicines have some unwanted side effects. Sometimes they are serious, but most of the time they are not. You may need medical attention if you get some of the side effects.

Do not be alarmed by this list of possible side effects. You may not experience any of them.

Ask your doctor or pharmacist to answer any questions you may have.

Tell your doctor or pharmacist if you notice any of the following and they worry you:

  • skin irritations
  • stomach upsets
  • dizziness
  • fast heart beat
  • headache
  • difficulty sleeping (insomnia)

The above list includes the more common side effects of your medicine. They are usually mild and short-lived.

Stomach upsets can be overcome by taking Serc during meals.

Tell your doctor as soon as possible if you notice any of the following:

  • skin reactions
  • difficulty breathing

The above list includes serious side effects that may require medical attention. Serious side effects are rare.

Tell your doctor or pharmacist if you notice anything else that is making you feel unwell.

After using Serc


Keep your tablets in the pack until it is time to take them.

If you take the tablets out of the box or the blister pack they may not keep well.

Keep the medicine in a cool, dry place where the temperature stays below 30°C.

Do not store it or any other medicine in the bathroom, near a sink, or on a windowsill. Do not leave it in the car.

Heat and dampness can destroy some medicines.

Keep it where children cannot reach it.

A locked cupboard at least one-and-a-half metres above the ground is a good place to store medicines.


If your doctor or pharmacist tells you to stop taking this medicine, or the medicine has passed its expiry date, ask your pharmacist what to do with any that are left over.

Product description

What it looks like

SERC tablets 16 mg are uncoated white, round, and scored, with "267" on either side of the score.

Serc 16 mg tablets are available in packs of 10 and 25 tablets.


Serc contains 16 mg of betahistine dihydrochloride as the active ingredient:

It also contains

  • colloidal anhydrous silica
  • microcrystalline cellulose
  • mannitol
  • citric acid monohydrate
  • purified talc

Serc does not contain gluten, sucrose, lactose monohydrate, tartrazine or any other azo dyes.


Serc is made in France .

Serc is supplied in Australia by:

Mylan Health Pty Ltd
Level 1, 30 The Bond
30-34 Hickson Road
Millers Point NSW 2000
Phone: 1800 314 527

® Registered Trademark

This leaflet was prepared September 2017.

Australian Registration Number(s)
16 mg tablet: AUST R 61687


Brand name

Serc Tablets

Active ingredient

Betahistine dihydrochloride




1 Name of Medicine

Betahistine dihydrochloride.

6.7 Physicochemical Properties

Betahistine dihydrochloride is a white to almost white crystalline powder which is very hygroscopic. The product is very soluble in water, freely soluble in methanol and 96% ethanol, and slightly soluble in isopropanol. The pKa values are 3.5 and 9.7.

Chemical formula.

Betahistine dihydrochloride is chemically identified as 2-[2-methylamino (ethyl)] pyridine dihydrochloride. Chemically, betahistine has a close resemblance to histamine.

Molecular weight.


Chemical structure.

CAS number.

(CAS) Registry Number: 5579-84-0.

2 Qualitative and Quantitative Composition

Active ingredient is betahistine dihydrochloride.
Each tablet contains 16 mg of betahistine dihydrochloride.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Serc (betahistine dihydrochloride) 16 mg tablets: round, biconvex, scored, white to almost white uncoated tablet, one side inscribed with '267' on either side of the score.
Serc (betahistine dihydrochloride) *8 mg tablets: round, flat, white to almost white uncoated tablet, one side inscribed with '256'.

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

The mechanism of action of betahistine is not known. Pharmacological testing in animals has shown that the blood circulation in the striae vascularis of the inner ear improves, probably by means of a relaxation of the precapillary sphincters of the microcirculation of the inner ear.
In further animal pharmacological studies, betahistine was found to have weak H1 receptor agonistic and considerable H3 antagonistic properties in the CNS and autonomic nervous system. Betahistine was also found to have a dose dependent inhibiting effect on spike generation of neurons in lateral and medial vestibular nuclei in cats. The importance of this observation in the action against Meniere's syndrome or vestibular vertigo, however, remains unclear.

Clinical trials.

No data available.

5.2 Pharmacokinetic Properties


In man, orally administered doses of betahistine dihydrochloride are rapidly and completely absorbed from the gastrointestinal tract.


The drug is rapidly metabolised to one major metabolite, 2-pyridylacetic acid.


Urinary excretion of the label was about 90% complete within 24 hours of administration. Studies with radio-labelled betahistine have demonstrated a plasma half-life of 3.4 hours and a urinary half-life of 3.5 hours for the radio-label.

5.3 Preclinical Safety Data


No animal data is available on the carcinogenic or mutagenic potential of betahistine.


See Section 5.3 Preclinical Safety Data, Genotoxicity.

4 Clinical Particulars

4.1 Therapeutic Indications

Meniere's Syndrome as defined by the following core symptoms:
vertigo (with nausea/vomiting);
hearing loss (hardness of hearing);

4.3 Contraindications

Serc (betahistine dihydrochloride) Tablets are contraindicated as follows:
during pregnancy and lactation;
in children less than 18 years;
in patients suffering from phaeochromocytoma;
in patients with active peptic ulcer or a history of this condition;
in patients with hypersensitivity to any component to the product (see Section 2 Qualitative and Quantitative Composition; Section 6 Pharmaceutical Particulars; Section 6.1 List of Excipients).

4.4 Special Warnings and Precautions for Use

Patients with bronchial asthma need to be carefully monitored during therapy.
Caution should be taken in the treatment of patients receiving antihistamines (see Section 4.5 Interactions with Other Medicines and Other Forms of Interactions).

Use in the elderly.

No data available.

Paediatric use.

Due to lack of clinical experience, betahistine dihydrochloride should not be used in children less than 18 years (see Section 4 Clinical Particulars; Section 4.3 Contraindications).

Effects on laboratory tests.

No data available.

4.5 Interactions with Other Medicines and Other Forms of Interactions

In vitro data indicate an inhibition of betahistine metabolism by drugs that inhibit monoamine oxidase (MAO) including MAO subtype B (e.g. selegiline). Caution is recommended when using betahistine and MAO inhibitors (including MAO B selective) concomitantly.
An antagonism between Serc and antihistamines could be expected on a theoretical basis. However, no such interactions have been reported.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

Studies in animals are inadequate or may be lacking, but available data show no evidence of an increased occurrence of foetal damage.
(Category B2)
Betahistine dihydrochloride should not be used during pregnancy (see Section 4 Clinical Particulars; Section 4.3 Contraindications), since there are insufficient data on the use of this drug during pregnancy to evaluate possible harmful effects. Studies in animals are inadequate or may be lacking, but available data show no evidence of an increased occurrence of foetal damage.
Betahistine dihydrochloride should not be used during lactation (see Section 4 Clinical Particulars; Section 4.3 Contraindications).

4.8 Adverse Effects (Undesirable Effects)

Most of the reported adverse reactions pertain to the skin, gastrointestinal tract, body as a whole, nervous system, respiratory system and cardiovascular system.
Events are listed within body systems and categorised by frequency according to the following definitions: common (frequency ≥ 1 and < 10%); uncommon (frequency ≥ 0.1% and < 1%); rare (frequency ≥ 0.01% and < 0.1%); very rare (frequency < 0.01%).

Skin and subcutaneous tissue disorders.

Rare: various types of rash, pruritus and urticaria/angioneurotic oedema. These reactions are probably related to the histamine-like structure of betahistine.
There was a single case of Stevens-Johnson syndrome.

Body as a whole.

Common: headache.
Rare: tiredness and malaise.

Gastrointestinal system.

Common: nausea and dyspepsia.
Rare: vomiting, diarrhoea, abdominal distension, bloating and epigastric pain have been reported. These symptoms were usually mild.
Gastrointestinal disturbances may be relieved by reducing the dose or by taking betahistine with meals.

Nervous system.

Rare: dizziness.
Very rare: convulsions, somnolence, confusion and hallucinations.
Some of these symptoms may also be observed as part of the disease condition and are usually resolved without changes to the treatment schedule.
Patients with neurological events usually presented with confounding factors.

Cardiovascular system.

Very rare: vasodilation, postural hypotension and tachycardia.

Respiratory system.

Very rare: dyspnoea, asthma and bronchospasms (see Section 4.4 Special Warnings and Precautions for Use).

Immune system disorders.

Hypersensitivity reactions, e.g. anaphylaxis, have been reported.

Reporting suspected adverse effects.

Reporting suspected adverse reactions after registration of the medicinal product is important. It allows continued monitoring of the benefit-risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions at

4.2 Dose and Method of Administration

The recommended starting dose in adults is 8 to 16 mg three times a day. The maximum recommended daily dose is 48 mg.
The tablets may be taken with or without food. However, if gastrointestinal upset occurs, it is recommended that the tablets be taken with meals.
The dosage should be individually adapted according to the response. Improvement in symptoms may be observed in the first few days to weeks of treatment.

4.7 Effects on Ability to Drive and Use Machines

The effects of this medicine on a person's ability to drive and use machines were not assessed as part of its registration.

4.9 Overdose

There have been a few cases of overdosage reported. Although in most cases no overdose symptoms were reported, some patients have experienced mild to moderate symptoms of overdosage including nausea, dry mouth, epigastric pain and sleepiness at doses above 200 mg. A case of convulsion was reported at a dose of 728 mg. In all cases recovery was complete. Treatment should include standard supportive measures.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).

7 Medicine Schedule (Poisons Standard)


6 Pharmaceutical Particulars

6.1 List of Excipients

Serc (betahistine dihydrochloride) is available as 16 mg uncoated tablets. The inactive ingredients in Serc 16 mg tablets are: colloidal anhydrous silica, microcrystalline cellulose, mannitol, citric acid monohydrate, and purified talc.

6.2 Incompatibilities

See Section 4.5 Interactions with Other Medicines and Other Forms of Interactions.

6.3 Shelf Life

In Australia, any unused medicine or waste material should be disposed of in accordance with local requirements.

6.4 Special Precautions for Storage


Store below 30°C, protect from light.

6.5 Nature and Contents of Container

8 mg: PVC/PVDC/aluminium blister packs containing 10 tablets and 120 tablets.
16 mg: PVC/PVDC/aluminium blister packs containing 10 tablets (sample pack), 25 tablets and *100 tablets.
*Not currently distributed in Australia.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of by taking it to your local pharmacy.

Summary Table of Changes