Pyridoxine antiparkinsonian drug

INTRODUCTION

Related to naturally occurring vitamin B6 activity

Source: liver, meat, egg, soybean vegetable and whole grain.
Absorption and fate of all three form of the vitamin are well absorbed from intestine. They are oxidized in body and excrete as pyridoxic, little is stored.

THERAPEUTIC USE
•Prophylactic ally in alcoholics infants and patients with other vitamin B deficiency
•To prevent and treat isoniazid hydralazine and cycloserine induce neurological disturbance.
•To treat mental symptoms in women on oral contraceptives
•It responsive anaemia and homocystinuria are rare genetic disorders that can be treated with high dose.
•Convulsions in infants and Children.

ADVERSE EFFECT
Large intake of this drug can result in dependence, and mega doses have been linked with sensory neuropathy. Other than is it is free from side effects and adverse reactions. However suppression of lactation has been noted in no suckling postpartum women given high dose of this drug.

 DRUG-DRUG INTERACTIONS
•Isoniazid + pyriodoxal= form hydrazones and inhibits generations of pyriodoxal sulfate.
•Isoniazide+ pyriodoxal sulfate= increase the renal excretion of the compound
•Hydralazine + drug= decrease the actions of drug
Cycloserine+ drug= decrease the actions of drug
Oral contraceptives + pyriodoxal= amount decreases in women.
•4-deoxypyridoxine + drug = acts as antagonist for the drug. stops its effect

MECHANISM OF ACTION
Pyridoxal is phosphorylated into pyridoxal phosphate which is the coenzyme form. These pyriodoxal dependent enzyme include transaminases and decarboxylase involve in synthesis of non essential amino acids., tryptophan and sulfur containing  amino acid metabolize, formation of 5HT and dopamine,histamine,GABA and aminoevulinic acid occurs. More protein diet more is the requirement of vitamin B6.

PHARMACOKINETICS
It is absorbed in all forms through intestine. oxidized in body and excreted as pyridoxic acid, very less amount is stored . Excretion occurs through kidney.

REFERENCE -Tripathi;k.d "Essential of medical pharmacology"page no-429,