indication

For treatment of folic acid deficiency, megaloblastic anemia and in anemias of nutritional supplements, pregnancy, infancy, or childhood.

pharmacology

Folic acid, a water-soluble B-complex vitamin, is found in foods such as liver, kidneys, yeast, and leafy, green vegetables. Folic acid is used to diagnose folate deficiency and to treat topical sprue and megaloblastic and macrocytic anemias, hematologic complications resulting from a deficiency in folic acid.

mechanism of action

Folic acid, as it is biochemically inactive, is converted to tetrahydrofolic acid and methyltetrahydrofolate by dihydrofolate reductase. These folic acid congeners are transported across cells by receptor-mediated endocytosis where they are needed to maintain normal erythropoiesis, synthesize purine and thymidylate nucleic acids, interconvert amino acids, methylate tRNA, and generate and use formate. Using vitamin B12 as a cofactor, folic acid can normalize high homocysteine levels by remethylation of homocysteine to methionine via methionine synthetase.

toxicity

IPR-MUS LD₅₀ 85 mg/kg,IVN-GPG LD₅₀ 120 mg/kg, IVN-MUS LD₅₀ 239 mg/kg, IVN-RAT LD₅₀ 500 mg/kg, IVN-RBT LD₅₀ 410 mg/kg

biotransformation

Hepatic

route of elimination

Folic Acid is metabolized in the liver to 7, 8-dihydrofolic acid and eventually to 5,6,7,8-tetrahydrofolic acid with the aid of reduced diphosphopyridine nucleotide (DPNH) and folate reductases. A majority of the metabolic products appeared in the urine after 6 hours; excretion was generally complete within 24 hours. Folic Acid is also excreted in the milk of lactating mothers.

drug interactions

Amobarbital: Folic acid decreases the effect of anticonvulsant, amobarbital.

Aprobarbital: Folic acid decreases the effect of anticonvulsant, aprobarbital.

Butabarbital: Folic acid decreases the effect of anticonvulsant, butabarbital.

Butalbital: Folic acid decreases the effect of anticonvulsant, butalbital.

Butethal: Folic acid decreases the effect of anticonvulsant, butethal.

Dihydroquinidine barbiturate: Folic acid decreases the effect of anticonvulsant, dihydroquinidine barbiturate.

Ethotoin: Folic acid decreases the levels of hydantoin

Fosphenytoin: Folic acid decreases the levels of hydantoin

Heptabarbital: Folic acid decreases the effect of anticonvulsant, heptabarbital.

Hexobarbital: Folic acid decreases the effect of anticonvulsant, hexobarbital.

Mephenytoin: Folic acid decreases the levels of hydantoin

Methohexital: Folic acid decreases the effect of anticonvulsant, methohexital.

Methylphenobarbital: Folic acid decreases the effect of anticonvulsant, methylphenobarbital.

Pentobarbital: Folic acid decreases the effect of anticonvulsant, pentobarbital.

Phenobarbital: Folic acid decreases the effect of anticonvulsant, phenobarbital.

Phenytoin: Folic acid may decrease the levels of phenytoin.

Primidone: Folic acid decreases the effect of anticonvulsant, primidone.

Quinidine barbiturate: Folic acid decreases the effect of anticonvulsant, quinidine barbiturate.

Secobarbital: Folic acid decreases the effect of anticonvulsant, secobarbital.

Talbutal: Folic acid decreases the effect of anticonvulsant, talbutal.