Notes
Distributed by Generic Health Pty Ltd
1 Name of Medicine
Betahistine dihydrochloride.
2 Qualitative and Quantitative Composition
Betahistine Lupin tablets contain 16 mg of betahistine dihydrochloride.
List of excipients with known effects.
Sugars as lactose.
For the full list of excipients, see Section 6.1 List of Excipients.3 Pharmaceutical Form
Betahistine Lupin tablets are white flat round tablets with bevelled edges and a breakline on one side.
4.1 Therapeutic Indications
Meniere's syndrome as defined by the following core symptoms: vertigo (with nausea/ vomiting); hearing loss (hardness of hearing); tinnitus.
4.2 Dose and Method of Administration
Dosage.
The recommended starting dose in adults is one-half to one tablet (8 to 16 mg) taken three times a day. The maximum recommended daily dosage is 48 mg. 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.
Method of administration.
The tablets may be taken with or without food. However, if gastrointestinal upset occurs, it is recommended that the tablets be taken with meals.4.3 Contraindications
Betahistine Lupin (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 6.1 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 4.3 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 betahistine dihydrochloride 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.
There are no animal data on the effects of betahistine on fertility.
(Category B2)
Betahistine dihydrochloride must not be used during pregnancy (see Section 4.3 Contraindications), since there are insufficient data on the use of this drug during pregnancy to evaluate possible harmful effects.
Betahistine dihydrochloride must not be used during lactation (see Section 4.3 Contraindications).4.7 Effects on Ability to Drive and Use Machines
Betahistine is indicated for Meniere's syndrome defined by the triad of core symptoms vertigo, hearing loss and tinnitus which can negatively affect the ability to drive and use machines. In a clinical study (12 healthy volunteers) specifically designed to investigate the ability to drive, betahistine had no or negligible effects compared to placebo.
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:
Very common (> 1/10); common (frequency greater than or equal to 1 and < 10%); uncommon (frequency greater than or equal to 0.1% and < 1%); rare (frequency greater than or equal to 0.01% and < 0.1%); very rare (frequency < 0.01%).
Skin and subcutaneous tissue disorders.
Rare: various types of rash, pruritus and urticaria/ angioedema. 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.
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.
Common: headache.
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 disorder.
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 http://www.tga.gov.au/reporting-problems.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 Poison Information Centre on 131126 (Australia).
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
Absorption.
In humans, orally administered doses of betahistine dihydrochloride are rapidly and completely absorbed from the gastrointestinal tract.
Distribution.
No data available.
Metabolism.
The drug is rapidly metabolised to one major metabolite, 2-pyridylacetic acid.
Excretion.
The drug is excreted in the urine. 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 radiolabel. Urinary excretion of the label was about 90% complete within 24 hours of administration.
5.3 Preclinical Safety Data
Genotoxicity.
No animal data are available on the mutagenic potential of betahistine.
Carcinogenicity.
No animal data are available on the carcinogenic potential of betahistine.6 Pharmaceutical Particulars
6.1 List of Excipients
Lactose monohydrate, maize starch, microcrystalline cellulose, citric acid, povidone, crospovidone and hydrogenated vegetable oil.
6.2 Incompatibilities
See Section 4.5 Interactions with Other Medicines and Other Forms of Interactions.
6.3 Shelf Life
In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG). The expiry date can be found on the packaging.
6.4 Special Precautions for Storage
Stored below 25°C.
6.5 Nature and Contents of Container
Betahistine Lupin tablets are presented in PVC/PE/PVDC/Al blister packs of 25 tablets.
6.6 Special Precautions for Disposal
In Australia, any unused medicine or waste material should be disposed of by taking to your local pharmacy.
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 structure.
Chemical name: 2-[2-ethylamino)ethyl]pyridine dihydrochloride.
Molecular formula: C8H14Cl2N2.
Molecular weight: 209.1.
CAS number.
5579-84-0.
Chemically, betahistine has a close resemblance to histamine.7 Medicine Schedule (Poisons Standard)
S4 - Prescription Only Medicine.
Summary Table of Changes
