Indications

Pyridoxine Hydrochloride is indicated in- Treatment and prevention of pyridoxine deficiency states Sideroblastic anaemias Seizures due to hereditary syndromes of pyridoxine deficiency or dependency in infants Depression and other symptoms associated with premenstrual syndrome & the use of oral contraceptives. Prophylaxis of isoniazid-induced peripheral neuritis and for the treatment of acute isoniazid toxicity.

Composition

Pharmacology

Vitamin B6 (pyridoxine) is a water-soluble vitamin used in the prophylaxis and treatment of vitamin B6 deficiency and peripheral neuropathy in those receiving isoniazid (isonicotinic acid hydrazide, INH). Vitamin B6 has been found to lower systolic and diastolic blood pressure in a small group of subjects with essential hypertension. Hypertension is another risk factor for atherosclerosis and coronary heart disease. Another study showed pyridoxine hydrochloride to inhibit ADP- or epinephrine-induced platelet aggregation and to lower total cholesterol levels and increase HDL-cholesterol levels, again in a small group of subjects. Vitamin B6, in the form of pyridoxal 5'-phosphate, was found to protect vascular endothelial cells in culture from injury by activated platelets. Endothelial injury and dysfunction are critical initiating events in the pathogenesis of atherosclerosis. Human studies have demonstrated that vitamin B6 deficiency affects cellular and humoral responses of the immune system. Vitamin B6 deficiency results in altered lymphocyte differentiation and maturation, reduced delayed-type hypersensitivity (DTH) responses, impaired antibody production, decreased lymphocyte proliferation and decreased interleukin (IL)-2 production, among other immunologic activities.

Dosage & Administration

Oral use: General deficiency states: Upto 150 mg (6 tabs.) daily. Sideroblastic anaemias: Upto 400 mg (16 tabs.) daily. Premenstrual syndrome: 50 to 100 mg (2 to 4 tabs.) daily. Peripheral neuritis: Prophylaxis: 10 to 50 mg (2 tabs.) daily. Treatment: 100 to 200 mg (4 to 8 tabs.) daily.

Contraindications

It should not be given to patients receiving levodopa (in parkinson's disease). Pyridoxine (80 to 400 mg daily) has been reported to enhance the hepatic metabolism of phenobarbitone or phenytoin by 40-50% in some patients. This reduces the serum drug concentration.

Side Effects

Long-term use of pyridoxine in large doses (excess of about 2g daily) is associated with the development of severe peripheral neuropathies. Excessive doses of pyridoxine may lower serum folate concentrations.

Pregnancy & Lactation

The requirement of pyridoxine appears to be increased during pregnancy. Pyridoxine is sometimes of value in the treatment of nausea and vomiting of pregnancy. The need of pyridoxine is increased during lactation. Caution should be exercised when pyridoxine is administered to a nursing woman.

Precautions & Warnings

Pyridoxine reduces the effects of levodopa, but this does not occur if a dopa decarboxylase inhibitor is also given. Many drugs may alter either the metabolism or bioavailability of pyridoxine; such agents include isoniazid, penicillamine and oral contraceptives.

Therapeutic Class

Vitamin-B preparations

Storage Conditions

Store under normal storage condition (15°C to 30°C). Protect from light.