FOLICET
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FOLICET (FOLICET).
Folic acid is reduced to tetrahydrofolate (THF) through the enzyme dihydrofolate reductase. THF is a cofactor in one-carbon transfer reactions involved in purine and pyrimidine synthesis, and amino acid metabolism, essential for DNA synthesis and cell division.
| Metabolism | Folic acid is reduced to dihydrofolate (DHF) then to tetrahydrofolate (THF) via dihydrofolate reductase (DHFR). Further metabolism involves conversion to polyglutamates and methylated forms, primarily in the liver. |
| Excretion | Primarily renal elimination: approximately 80% of the dose is excreted unchanged in urine via glomerular filtration and active tubular secretion. Biliary/fecal excretion accounts for <15%. |
| Half-life | Terminal elimination half-life is 3-5 hours in adults with normal renal function; may be prolonged up to 12-24 hours in severe renal impairment (CrCl <30 mL/min). |
| Protein binding | Approximately 30-40% bound to serum albumin. |
| Volume of Distribution | 0.2-0.4 L/kg, indicating distribution primarily in extracellular fluid. |
| Bioavailability | Oral bioavailability is 50-70% due to first-pass metabolism. Intravenous bioavailability is 100%. |
| Onset of Action | Oral: 30-60 minutes; Intravenous: within 5-10 minutes. |
| Duration of Action | Approximately 6-8 hours for clinical effect, though duration may be extended in renal impairment due to reduced clearance. |
1 mg orally once daily. For treatment of megaloblastic anemia, up to 5 mg daily initially.
| Dosage form | TABLET |
| Renal impairment | No adjustment required. Folic acid is not significantly renally excreted. |
| Liver impairment | No adjustment required. Folic acid metabolism is not significantly impaired in hepatic disease. |
| Pediatric use | For megaloblastic anemia: 0.5-1 mg orally once daily. For supplementation: 0.1-1 mg daily depending on age and condition. |
| Geriatric use | No specific dose adjustment; use standard adult dosing. Monitor for underlying nutritional deficiencies. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for FOLICET (FOLICET).
| Breastfeeding | Folic acid is excreted into human breast milk. The M/P ratio is approximately 0.5. At recommended doses, it is considered compatible with breastfeeding. No adverse effects in nursing infants have been reported. |
| Teratogenic Risk | Folic acid is classified as FDA Pregnancy Category A. No fetal risks have been demonstrated in any trimester when used at recommended doses (0.4-5 mg/day). Supraphysiological doses (>5 mg/day) have not been associated with teratogenicity in human studies. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to folic acid or any component of the formulation"]
| Precautions | ["Folic acid should not be used alone for pernicious anemia or other vitamin B12 deficiency states as it may mask hematologic abnormalities while neurological damage progresses.","Seizures in epileptic patients on anticonvulsants may increase with folic acid.","Large doses may precipitate seizures in susceptible individuals."] |
Loading safety data…
| No specific monitoring is required beyond routine prenatal care. For women on high-dose folic acid (e.g., 4-5 mg for prevention of neural tube defects), periodic assessment of serum folate and vitamin B12 levels may be considered to avoid masking B12 deficiency. |
| Fertility Effects | Folic acid is essential for normal reproductive function. Deficiency may impair fertility. Supplementation in deficient individuals may improve fertility outcomes. No adverse effects on fertility have been reported at standard doses. |