• Prevention and treatment of megaloblastic and macrocytic anemias.
• Given during pregnancy to promote normal fetal development.

Contraindicated in:

• Uncorrected pernicious, aplastic, or normocytic anemias (neurologic damage will progress despite correction of hematologic abnormalities)
• Pedi: Preparations containing benzyl alcohol should not be used in newborns.

Use Cautiously in:

• Undiagnosed anemias.

Derm: rash.

Neuro: confusion, difficulty sleeping, irritability, malaise.
Misc: fever.

Drug-Drug:

• Pyrimethamine, methotrexate, trimethoprim, and triamterene prevent the activation of folic acid (leucovorin should be used instead to treat overdoses of these drugs).
• Absorption of folic acid is ↓ by sulfonamides (including sulfasalazine), antacids, and cholestyramine.
• Folic acid requirements are ↑ by estrogens, phenytoin, phenobarbital, primidone, carbamazepine, or corticosteroids.
• May ↓ phenytoin levels.

(Generic available)

• Solution for injection: 5 mg/mL;
• Tablets: 0.4 mg; 0.8 mg; 1 mg; 5 mg; 25 mg;
• In combination with: other vitamins and minerals as multiple vitamins^{Rx, OTC}.

Therapeutic Dose (Folic acid deficiency)

• PO, IM, IV, SC (Adults and Children >11 yr): 1 mg/day initial dose then 0.5 mg/day maintenance dose.
• PO, IM, IV, SC (Children >1 yr): 1 mg/day initial dose then 0.1–0.4 mg/day maintenance dose.
• PO, IM, IV, SC (Infants): 15 mcg/kg/dose daily or 50 mcg/day.

Recommended Daily Allowance

• PO (Adults and Children >15 yr): 0.2 mg/day.
• PO (Adults): Females of reproductive potential: 0.4–0.8 mg/day.
• PO (Children 11–14 yr): 0.15 mg/day.
• PO (Children 7–10 yr): 0.1 mg/day.
• PO (Children 4–6 yr): 0.075 mg/day.
• PO (Infants 6 mo–3 yr): 0.05 mg/day.

• Required for protein synthesis and red blood cell function. Stimulates the production of red blood cells, white blood cells, and platelets. Necessary for normal fetal development.

• Restoration and maintenance of normal hematopoiesis.

Therapeutic Classification: antianemics, vitamins

Pharmacologic Classification: water soluble vitamins

Absorption: Well absorbed from the GI tract and IM and SUBQ sites.

Distribution: Half of all stores are in the liver. Enters breast milk. Crosses the placenta.

Protein Binding: Extensive.

Metabolism/Excretion: Converted by the liver to its active metabolite, dihydrofolate reductase. Excess amounts are excreted unchanged by the kidneys.

Half-life: Unknown.

(↑ in reticulocyte count)

• Encourage patient to comply with diet recommendations of health care professional. Explain that the best source of vitamins is a well-balanced diet with foods from the 4 basic food groups. A diet low in vitamin B and folate will be used to diagnose folic acid deficiency without concealing pernicious anemia.
• Folic acid in early pregnancy is necessary to prevent neural tube defects.
• Foods high in folic acid include vegetables, fruits, and organ meats; heat destroys folic acid in foods.
• Patients self-medicating with vitamin supplements should be cautioned not to exceed RDA. The effectiveness of megadoses for treatment of various medical conditions is unproven and may cause side effects.
• Explain that folic acid may make urine more intensely yellow.
• Instruct patient to notify health care professional if rash occurs, which may indicate hypersensitivity.
• Emphasize the importance of follow-up exams to evaluate progress.

FOE-lik A -sid