Folic Acid Sunward Special Precautions

Folic acid should never be given alone or in conjunction with inadequate amounts of hydroxocobalamin for the treatment of megaloblastic or pernicious anaemia. Though folic acid produces a haemopoietic response, it fails to prevent the onset of subacute combined degeneration of the cord. Folic acid should not be given before a diagnosis has been fully established. Large and continuous doses of folic acid may lower the blood concentration of vitamin B12. The availability of folates may be inhibited by gastric acidity and the presence of ascorbate in the gastrointestinal tract.
Metformin reduces intestinal absorption of folic acid and phenytoin may cause folate depletion. Folic acid does not correct folate deficiency due to dihydrofolate reductase inhibitors.