APO-PYRIDOXINE 25mg tablets are white, round, 7mm in diameter, flat with beveled edge. Each tablet contains 25mg pyridoxine hydrochloride and typically weighs 118mg. APO-PYRIDOXINE 50mg tablets are white, round, 8.7mm in diameter, biconvex, engraved with "APO" on one side and "PYR" over "50" on the other side. Each tablet contains 50mg pyridoxine hydrochloride and typically weighs 235mg. APO-PYRIDOXINE 100mg tablets are white, round, 11mm in diameter, biconvex. Each tablet contains 100mg pyridoxine hydrochloride and typically weighs 470mg.
Pyridoxine (vitamin B6) is a water-soluble vitamin involved principally in amino acid metabolism, but is also involved in carbohydrate and fat metabolism. It is also required for the formation of haemoglobin. Pyridoxine deficiency is rare in humans because of its widespread distribution in foods. Pyridoxine deficiency may be drug induced, and inadequate utilization of pyridoxine may result from certain inborn errors of metabolism. Pyridoxine deficiency may lead to sideroblastic anaemia, dermatitis, cheilosis and neurological symptoms such as peripheral neuritis and convulsions.
Pyridoxine is readily absorbed from the gastrointestinal tract after oral administration and converted to the active forms pyridoxal phosphate and pyridoxamine phosphate. They are stored mainly in the liver where there is metabolisation to 4-pyridoxic acid and other inactive metabolites which are excreted in the urine. As the dose increases proportionally greater amounts are excreted unchanged in the urine. Vitamin B6 crosses the placenta and also appears in breast milk.
The prevention and management of vitamin B6 deficiency. Treatment of sideroblastic anaemias, homocystinuria or primary hyperoxaluria. Vitamin B6 dependency in infants.
In preventing vitamin deficiencies adequate dietary intake is preferred over supplementation whenever possible. An adequate human diet in most circumstances is one containing between 1 and 2 mg vitamin B6 daily. Doses of up to 150 mg daily have been used in general deficiency states. Higher doses of between 200-600 mg daily have been used in the treatment of sideroblastic anaemias, with similar doses being used to teat certain metabolic disorders such as homocystinuria or primary hyperoxaluria. Lifelong supplementation may be required to prevent reoccurrence. Some infants require i.m. or i.v. administration for seizures due to vitamin B6 dependency and some may require lifelong supplementation with oral doses of 2-100mg.
Hypersensitivity to pyridoxine hydrochloride.
Vitamin B6 is relatively nontoxic at normal doses however long-term administration of high doses (2-6g daily) is associated with the development of severe peripheral neuropathies. There have been reports of doses of 500mg daily having a toxic effect. APO-PYRIDOXINE is presumed to be safe or unlikely to produce an effect on the ability to drive or use machinery
Daily dietary requirements may increase slightly during pregnancy. No adverse effects have been reported with the use of physiologic doses during pregnancy. However the use of high doses during pregnancy has been implicated in some cases of vitamin B6 dependent syndrome in infants. Vitamin B6 is excreted in breast milk however no adverse effects have been reported with the use of physiologic doses during lactation.
Nausea, headache, paresthesia, somnolence and low serum folic acid concentrations have been reported. Vitamin B6 is relatively nontoxic at normal doses however long-term administration of high doses (2-6g daily) is associated with the development of severe peripheral neuropathies. There have been reports of doses of 500mg daily having a toxic effect. Transient dependency symptoms may occur upon withdrawal of therapy at a dose of 200mg/day for over 1 month. The significance of this is not known however for patients on large doses for long period of time withdrawal of therapy should probably be gradual.
Pyridoxine increases the peripheral metabolisation of levodopa. When levodopa is combined with carbidopa this effect is prevented. Isoniazid, cycloserine, pyrazinamide and penicillamine may antagonise the effects of pyridoxine and lead to a secondary deficiency. It has been reported that pyridoxine decreases serum concentrations of phenobarbitone. Patients taking oestrogens e.g. oral contraceptives have higher vitamin B6 requirements.
Sensory neuropathy can occur following long term administration of large doses. Withdrawal should be started but should probably be gradual to prevent the occurrence of transient dependency symptoms.
Shelf life: 48 months from the date of manufacture Store below 30C. Protect from heat, light and moisture. Keep container tightly closed.
General Sale Medicine
APO-PYRIDOXINE 50mg - Bottles of 500. APO-PYRIDOXINE 25mg and APO- PYRIDOXINE 100mg are currently not marketed.
Pyridoxine has been widely used in premenstrual syndrome despite controversy over its effectiveness. Doses of up to 100mg daily from either the onset of symptoms or for 14 days prior to the start of menstruation have been used. Concerns exist about the possibility of neurotoxicity occurring.
Apotex NZ Ltd. 32 Hillside Road Glenfield Private Bag 102995 North Shore North Shore City 0745 Tel: (09) 444-2073 Fax: (09) 444-2951
01 March 2010