COMPOSITION Each Serc tablet contains betahistine dihydrochloride 4 mg.
PHARMACOLOGICAL CLASSIFICATION A. 5.6 Histamine.
PHARMACOLOGICAL ACTION Betahistine dihydrochloride is an analogue of histamine. Betahistine dihydrochloride is readily absorbed from the gastrointestinal tract. It is converted to two metabolites and peak concentrations in blood of the two metabolites are achieved within 3 to 5 hours. Most of a dose is excreted in the urine, in the form of the metabolites, in about 3 days.
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 pharmacological studies, betahistine was found to have weak H1 receptor agonistic and considerable H3 antagonistic properties in the central nervous system 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. The importance of this observation in the action against Ménières syndrome or vestibular vertigo, however, remains unclear.
INDICATIONS Ménières syndrome.
CONTRA-INDICATIONS Hypersensitivity to any of the ingredients.
Patients with active peptic ulcer.
Patients with phaeochromocytoma.
DOSAGE AND DIRECTIONS FOR USE
Two to four tablets three times daily with meals.
Six to twelve tablets daily.
SIDE EFFECTS AND SPECIAL PRECAUTIONS Gastro-intestinal disturbances, headache and skin rashes have been reported. Special precautions Serc tablets should be given with care to patients with asthma, peptic ulcer or a history of peptic ulcer.
Serc tablets should not be given concomitantly with antihistamines. There is insufficient data on the use of this medicine during pregnancy and lactation.
KNOWN SYMPTOMS OF OVERDOSAGE AND PARTICULARS OF ITS TREATMENT In the case of severe overdosage the stomach should be emptied by aspiration and lavage. If necessary, the circulation should be maintained by infusion of suitable electrolyte solutions. Treatment is symptomatic and supportive.
IDENTIFICATION Serc tablets are pink-coloured, small round, biconvex and single-scored on one side.
PRESENTATION Bottles of 100 tablets.
STORAGE INSTRUCTIONS Store below 25°C. Protect from moisture. Keep bottle tightly closed and out of reach of children.
REFERENCE NUMBER C.644 (Act 101/1965)
NAME AND BUSINESS ADDRESS OF THE APPLICANT Schering (Pty) Ltd
(Reg No: 1964/09072/07)
106 Sixteenth Road
P O Box 5278
Halfway House 1685
DATE OF PUBLICATION OF THIS PACKAGE INSERT 21 February 1997