देश: ऑस्ट्रेलिया
भाषा: अंग्रेज़ी
स्रोत: Department of Health (Therapeutic Goods Administration)
betahistine dihydrochloride
Southern Cross Pharma Pty Ltd
betahistine dihydrochloride
________________________________________________________________________________ C: Products/Betahistine/CMI 3Feb15 Page 1 of 3 BETAHISTINE AN _Betahistine dihydrochloride_ CONSUMER MEDICINE INFORMATION _ _ PLEASE READ THIS LEAFLET CAREFULLY BEFORE YOU START BETAHISTINE AN. What is in this leaflet This leaflet answers some common questions about Betahistine AN tablets. It does not contain all of the available information. It does not take the place of talking to your doctor or pharmacist. IF YOU HAVE ANY CONCERNS ABOUT TAKING THIS MEDICINE, ASK YOUR DOCTOR OR PHARMACIST. All medicines have risks and benefits. Your doctor has weighed the risks of you taking Betahistine AN tablets against the benefits this medicine is expected to have for you. KEEP THIS LEAFLET WITH THE MEDICINE. You may need to read it again. What Betahistine AN is used for Betahistine AN is used to treat a disorder of the working 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 Méniere's Syndrome. Based on animal studies, the active ingredient of Betahistine AN tablets, betahistine dihydrochloride, 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. YOUR DOCTOR MAY HAVE PRESCRIBED BETAHISTINE AN FOR ANOTHER REASON. ASK YOUR DOCTOR IF YOU HAVE ANY QUESTIONS ABOUT WHY BETAHISTINE AN HAS BEEN PRESCRIBED FOR YOU. There is no evidence that Betahistine AN is addictive. This medicine is available only with a doctor's prescription. Before you take Betahistine AN _When you must not take it _ DO NOT TAKE BETAHISTINE AN IF: you are pregnant or intend to become pregnant. Betahistine AN may affect your developing baby if taken during pr पूरा दस्तावेज़ पढ़ें
Betahistine/PI 04mar15 04/03/15 Page 1 of 5 PRODUCT INFORMATION BETAHISTINE AN NAME OF THE MEDICINE Betahistine dihydrochloride is chemically identified as 2-[2- ethylamino)ethyl]pyridine dihydrochloride. Molecular formula: C 8 H 14 Cl 2 N 2 MW: 209.1 The chemical structure of betahistine dihydrochloride is: CAS number: 5579-84-0 DESCRIPTION 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. Chemically, betahistine has a close resemblance to histamine. BETAHISTINE AN tablets contain Betahistine dihydrochloride 16 mg and the following excipients: Lactose, maize starch, microcrystalline cellulose, anhydrous citric acid, povidone, crospovidone and hydrogenated vegetable oil. PHARMACOLOGY PHARMACODYNAMICS 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. Betahistine/PI 04mar15 04/03/15 Page 2 of 5 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. PHARMACOKINETICS In humans, 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, and excreted in the urine. Studies with radiolabelled betahistine have demonstrated a plasma half-life of 3.4 hours पूरा दस्तावेज़ पढ़ें