FOLIC ACID (VITAMIN B₉, PTEROYLGLUTAMIC ACID)
(fol'ic)
Apo-Folic

, Folacin, Folvite, Novofolacid

FOLATE SODIUM
Folvite Sodium
Classifications: vitamin b₉
Pregnancy Category: A

Availability

0.4 mg, 0.8 mg, 1 mg tablets; 5 mg/mL injection

Actions

Vitamin B complex essential for nucleoprotein synthesis and maintenance of normal erythropoiesis. Acts against folic acid deficiency that impairs thymidylate synthesis and results in production of defective DNA that leads to megaloblast formation and arrest of bone marrow maturation.

Therapeutic Effects

Stimulates production of RBCs, WBCs, and platelets in patients with megaloblastic anemias. Include improved symptoms of glossitis, diarrhea, constipation, weight loss, irritability, fatigue, restless legs, diffuse muscular pain, insomnia, forgetfulness, mental depression, pallor.

Uses

Folate deficiency, macrocytic anemia, and megaloblastic anemias associated with malabsorption syndromes, alcoholism, primary liver disease, inadequate dietary intake, pregnancy, infancy, and childhood.

Contraindications

Folic acidalone for pernicious anemia or other vitamin B₁₂ deficiency states; normocytic, refractory, aplastic, or undiagnosed anemia.

Cautious Use

Pregnancy (category A), lactation.

Route & Dosage

Therapeutic
Adult: PO/IM/SC/IV

1 mg/d
Child: PO/IM/SC/IV

1 mg/d

Maintenance
Adult: PO/IM/SC/IV

0.4 mg/d
Child: PO/IM/SC/IV <4 y,

0.3 mg/d; >4 y,

0.4 mg/d
Infant: PO/IM/SC/IV

0.1 mg/d

Administration

Intravenous

PREPARE: Direct/Continuous: Given undiluted.

ADMINISTER: Direct/Continuous: Give over 30–60 sec. May also add to a continuous infusion.

INCOMPATIBILITIES Solution/additive: Doxapram.

Store at 15°–30° C (59°–86° F) in tightly closed containers protected from light, unless otherwise directed.

Adverse Effects (1%)

[Reportedly nontoxic. Slight flushing and feeling of warmth following IV administration.]

Diagnostic Test Interference

Falsely low serum folate levels may occur with Lactobacillus casei assay in patients receiving antibiotics such as tetracyclines.

Interactions

Drug: Chloramphenicol may antagonize effects of folate therapy; phenytoin metabolism may be increased, thus decreasing its levels in folate-deficient patients.

Pharmacokinetics

Absorption: Readily absorbed from proximal small intestine. Peak: 30–60 min PO. Distribution: Distributed to all body tissues; high concentrations in CSF; crosses placenta; distributed into breast milk. Metabolism: Metabolized in liver to active metabolites. Elimination: Small amounts eliminated in urine in folate-deficient patients; large amounts excreted in urine with high doses.

Nursing Implications

Assessment & Drug Effects

Obtain a careful history of dietary intake and drug and alcohol usage prior to start of therapy. Drugs reported to cause folate deficiency include oral contraceptives, alcohol, barbiturates, methotrexate, phenytoin, primidone, and trimethoprim. Folate deficiency may also result from renal dialysis.
Keep physician informed of patient's response to therapy.
Monitor patients on phenytoin for subtherapeutic plasma levels.

Patient & Family Education

Remain under close medical supervision while taking folic acid therapy. Adjustment of maintenance dose should be made if there is threat of relapse.
Do not breast feed while taking this drug without consulting physician.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug