FOLVITE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FOLVITE (FOLVITE).
Folate is reduced to tetrahydrofolate (THF) which acts as a cofactor for single-carbon transfer reactions in nucleic acid and amino acid synthesis.
| Metabolism | Metabolized by dihydrofolate reductase to dihydrofolate and then to tetrahydrofolate; primarily hepatic. |
| Excretion | Primarily excreted unchanged in urine (hepatic metabolism minimal); after oral doses, fecal excretion occurs via unabsorbed drug and biliary secretion of folate metabolites accounts for a minor route. |
| Half-life | Terminal elimination half-life of folic acid is approximately 0.7 hours; for the active metabolite 5-methyltetrahydrofolate, half-life is 3–4 hours in plasma (tissue stores have a much longer turnover). |
| Protein binding | Folic acid: approximately 50–60% bound to plasma proteins (mainly albumin); the active metabolite 5-methyltetrahydrofolate: about 60–70% bound. |
| Volume of Distribution | Apparent volume of distribution (Vd) for folic acid: approximately 0.6–0.8 L/kg, indicating distribution into total body water and tissues; hepatic folate stores are extensive. |
| Bioavailability | Oral folic acid: nearly 100% bioavailable when taken on an empty stomach; food may reduce absorption by up to 15%. Parenteral (IM/IV): 100% bioavailable. |
| Onset of Action | Oral: rapid absorption with detectable plasma levels within 15–30 minutes; hematopoietic response (reticulocytosis) in megaloblastic anemia begins within 2–5 days. IV/IM: immediate availability, clinical effects similar onset. |
| Duration of Action | Single oral dose: plasma levels decline rapidly, but tissue stores (e.g., liver) sustain folate activity for weeks; for daily supplementation, steady-state achieved in ~1–2 weeks. |
| Action Class | Haemopoetic agents |
| Brand Substitutes | Hiflo 5mg Tablet, Vitfol 5mg Tablet, Qfol 5mg Tablet, U-FOL 5mg Tablet, Folmine 5mg Tablet |
1 mg orally, intramuscularly, subcutaneously, or intravenously once daily for folic acid deficiency; for pregnant and lactating women: 0.4-0.8 mg orally once daily.
| Dosage form | INJECTABLE |
| Renal impairment | No dosage adjustment required for renal impairment; folic acid is removed by hemodialysis, consider supplementing 1 mg after each hemodialysis session. |
| Liver impairment | No dosage adjustment needed for hepatic impairment as folic acid is primarily metabolized in the liver to active forms; monitor folate levels in severe hepatic disease. |
| Pediatric use | Infants (1-6 months): 0.1 mg/day; children 1-10 years: 0.1-0.3 mg/day; children >=11 years: same as adult dose (1 mg/day). |
| Geriatric use | No specific dose adjustment; elderly may require 0.8 mg/day for folic acid deficiency due to decreased absorption; monitor vitamin B12 levels before supplementation to avoid masking B12 deficiency. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for FOLVITE (FOLVITE).
| Breastfeeding | Folic acid is excreted into breast milk in concentrations that support infant requirements. M/P ratio approximately 1.5. Considered compatible with breastfeeding; no adverse effects reported. |
| Teratogenic Risk | Folic acid is a vitamin essential for fetal neural tube development. Recommended supplementation during pregnancy to prevent neural tube defects. No known teratogenic risk; therapeutic doses are safe in all trimesters. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
Untreated vitamin B12 deficiency anemias (pernicious anemia)
| Precautions | May mask pernicious anemia due to vitamin B12 deficiency; use caution in patients with undiagnosed anemia. |
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| No specific monitoring required beyond routine prenatal care. Monitor maternal hemoglobin and folate levels in high-risk cases. |
| Fertility Effects | No adverse effects on fertility. Adequate folate status is important for reproductive function and early embryonic development. |