Effect of folic acid and vitamin B(12) administration on phenytoin induced toxicity in rats.

Folic acid and vitamin B(12) are very important vitamins needed for normal cellular metabolic activities. The effects of folic acid and vitamin B(12) on liver integrity of growing Wistar albino rats following therapeutic dose of phenytoin administration were investigated. The activities of serum AST, ALT, ALP were investigated. Serum total protein level and lipid profile were also measured as indices of biochemical changes. The ingestion of phenytoin alone in rats significantly reduced serum protein while AST, ALT activities incresed as compared to the control (P<0.05). Supplementation of phenytoin with oral administration of 70microgram/kg body wt of folic acid resulted in a significant reversal in serum total protein and suppression in serum AST and ALT activities. Vitamin B(12) supplementation did not afford any significant protection against the effect of phenytoin ingestion but rather phenytoin toxicity was exacerbated in this study. However, the combined effects of vitamin B(12) and folic acid ameliorated the effects of phenytoin on serum enzymes of experimental rats. The effect of combination of phenytoin with folic acid or folic acid and vitamin B(12) is an interesting finding. Supplementation of phenytoin with folic acid or combination of these vitamins may be recommended for the purpose of ameliorating the adverse biochemical changes which are associated with phenytoin therapy. Further work is ongoing to help elucidate the effects of phenytoin and these vitamins on oxidative stress inducing mechanism.