Folic Acid

folic acid (folacin, pteroylglutamic acid, folate) (foe' lik) Folvite Pregnancy Category A Drug class

Folic acid Vitamin supplement Therapeutic actions

Required for nucleoprotein synthesis and maintenence of normal erythropoiesis. Indications

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Treatment of megoblastic anemias due to sprue, nutritional deficiency, pregnancy, infancy, and childhood

Contraindications and cautions

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Contraindicated with allergy to folic acid preparations; pernicious, aplastic, normocytic anemias. Use cautiously during lactation.

Available forms

Tablets—0.4, 0.8, 1 mg; injection—5 mg/mL Dosages

Administer orally unless patient has severe intestinal malabsorption. ADULTS

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Therapeutic dose: Up to 1 mg/day PO, IM, IV, or SC. Larger doses may be needed in severe cases. Maintenance dose: 0.4 mg/day. Pregnancy and lactation: 0.8 mg/day.

PEDIATRIC PATIENTS

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Maintenance dose: Infants: 0.1 mg/day. < 4 yr: Up to 0.3 mg/day. > 4 yr: 0.4 mg/day.

Pharmacokinetics Route Oral, IM, SC, IV

Onset Varies

Peak 30–60 min

Metabolism: Hepatic; T1/2: Unknown Distribution: Crosses placenta; enters breast milk Excretion: Urine IV facts

Preparation: Solution is yellow to yellow-orange; may be added to hyperalimentation solution or dextrose solutions. Infusion: Infuse at rate of 5 mg/min by direct IV injection; may be diluted in hyperalimentation for continuous infusion. Adverse effects

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Hypersensitivity: Allergic reactions Local: Pain and discomfort at injection site

Interactions

Drug-drug • Decrease in serum phenytoin and increase in seizure activity with folic acid preparations • Decreased absorption with sulfasalazine, aminosalicyclic acid Nursing considerations CLINICAL ALERT!

Name confusion has been reported between folinic acid (leucovorin) and folic acid; use extreme caution. Assessment

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History: Allergy to folic acid preparations; pernicious, aplastic, normocytic anemias; lactation Physical: Skin lesions, color; R, adventitious sounds; CBC, Hgb, Hct, serum folate levels, serum vitamin B12 levels, Schilling test

Interventions

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Administer orally if at all possible. With severe GI malabsorption or very severe disease, give IM, SC, or IV. Test using Schilling test and serum vitamin B12 levels to rule out pernicious anemia. Therapy may mask signs of pernicious anemia while the neurologic deterioration continues. Use caution when giving the parenteral preparations to premature infants. These preparations contain benzyl alcohol and may produce a fatal gasping syndrome in premature infants. Monitor patient for hypersensitivity reactions, especially if drug previously taken. Keep supportive equipment and emergency drugs readily available in case of serious allergic response.

Teaching points

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When the cause of megaloblastic anemia is treated or passes (infancy, pregnancy), there may be no need for folic acid because it normally exists in sufficient quantities in the diet. Report rash, difficulty breathing, pain or discomfort at injection site.

Adverse effects in Italic are most common; those in Bold are life-threatening.