FOLVRON

Clinical safety rating: caution

Comprehensive clinical and safety monograph for FOLVRON (FOLVRON).

How it works

FOLVRON is a combination of iron, folic acid, and vitamin B12. Iron is essential for hemoglobin synthesis and oxygen transport, folic acid and vitamin B12 are cofactors in DNA synthesis and red blood cell maturation.

What the body does with it

Metabolism	Iron is absorbed in the duodenum and proximal jejunum; folic acid is metabolized in the liver to active forms; vitamin B12 undergoes hepatic metabolism and enterohepatic recycling.
Excretion	Folinic acid and its active metabolite 5-methyltetrahydrofolate are primarily excreted renally, with 80-90% of an administered dose recovered in urine. The remainder is excreted in feces via biliary elimination (10-20%).
Half-life	The terminal elimination half-life of folinic acid is approximately 6-7 hours. For its active metabolite 5-methyltetrahydrofolate, the half-life is about 10-12 hours. Clinically, this supports daily or twice-daily dosing in methotrexate rescue and other indications.
Protein binding	Folinic acid is approximately 15-20% bound to plasma proteins, primarily albumin. The metabolite 5-methyltetrahydrofolate has similar binding characteristics.
Volume of Distribution	Volume of distribution (Vd) is approximately 0.4-0.6 L/kg, indicating distribution into total body water and some tissue binding (e.g., liver and erythrocytes).
Bioavailability	Oral bioavailability is approximately 60-70% due to incomplete absorption and first-pass metabolism. Parenteral routes (IV, IM) provide 100% bioavailability.
Onset of Action	Oral: 30-60 minutes; Intravenous: <5 minutes; Intramuscular: 10-20 minutes. Clinical effect (e.g., reversal of methotrexate toxicity, hematopoietic response) is observed within 1-2 hours after IV administration.
Duration of Action	Duration of action is 4-8 hours after oral administration and 6-8 hours after parenteral administration. In methotrexate rescue, folinic acid is given every 6 hours for 72 hours to maintain protective folate levels.

Classification & Brands

Dosing & administration

1 tablet (ferrous fumarate 324 mg [106 mg elemental iron], folic acid 0.8 mg, vitamin C 75 mg) orally once daily.

Dosage form	CAPSULE
Renal impairment	Not required for iron supplementation; monitor iron levels in severe renal impairment (GFR <15 mL/min) due to risk of iron overload.
Liver impairment	No adjustment needed for iron; folic acid may require monitoring in severe hepatic impairment (Child-Pugh class C) due to altered folate metabolism.
Pediatric use	Not recommended for children under 12 years. For adolescents 12+, same as adult dose (1 tablet daily).
Geriatric use	No specific dose adjustment; monitor for constipation and iron overload, especially in patients with chronic disease or reduced clearance.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for FOLVRON (FOLVRON).

Breastfeeding	Cyanocobalamin and folic acid are excreted into breast milk in amounts that are not harmful to the nursing infant. Both are normal components of human milk. M/P ratio not available; however, supplementation is considered compatible with breastfeeding.
Teratogenic Risk	FOLVRON contains cyanocobalamin and folic acid. Both are essential for fetal development and are generally considered safe during pregnancy. There is no evidence of teratogenicity at recommended doses. However, high doses of folic acid ( >1 mg/day) may mask vitamin B12 deficiency. No known fetal risks in any trimester when used appropriately.

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to any component; hemochromatosis; hemosiderosis; pernicious anemia (folic acid may mask vitamin B12 deficiency); patients receiving repeated blood transfusions.

Clinical Precautions

Precautions

Accidental overdose of iron-containing products is a leading cause of fatal poisoning in children; avoid in patients with hemochromatosis or other iron overload disorders; monitor for hypersensitivity reactions; use with caution in patients with gastrointestinal disease.

Clinical Tips & Counseling

Drug interactions

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FOLVRON

Clinical safety rating: caution

Comprehensive clinical and safety monograph for FOLVRON (FOLVRON).

How it works

What the body does with it

Metabolism	Iron is absorbed in the duodenum and proximal jejunum; folic acid is metabolized in the liver to active forms; vitamin B12 undergoes hepatic metabolism and enterohepatic recycling.
Excretion	Folinic acid and its active metabolite 5-methyltetrahydrofolate are primarily excreted renally, with 80-90% of an administered dose recovered in urine. The remainder is excreted in feces via biliary elimination (10-20%).
Half-life	The terminal elimination half-life of folinic acid is approximately 6-7 hours. For its active metabolite 5-methyltetrahydrofolate, the half-life is about 10-12 hours. Clinically, this supports daily or twice-daily dosing in methotrexate rescue and other indications.
Protein binding	Folinic acid is approximately 15-20% bound to plasma proteins, primarily albumin. The metabolite 5-methyltetrahydrofolate has similar binding characteristics.
Volume of Distribution	Volume of distribution (Vd) is approximately 0.4-0.6 L/kg, indicating distribution into total body water and some tissue binding (e.g., liver and erythrocytes).
Bioavailability	Oral bioavailability is approximately 60-70% due to incomplete absorption and first-pass metabolism. Parenteral routes (IV, IM) provide 100% bioavailability.
Onset of Action	Oral: 30-60 minutes; Intravenous: <5 minutes; Intramuscular: 10-20 minutes. Clinical effect (e.g., reversal of methotrexate toxicity, hematopoietic response) is observed within 1-2 hours after IV administration.
Duration of Action	Duration of action is 4-8 hours after oral administration and 6-8 hours after parenteral administration. In methotrexate rescue, folinic acid is given every 6 hours for 72 hours to maintain protective folate levels.

Classification & Brands

Dosing & administration

1 tablet (ferrous fumarate 324 mg [106 mg elemental iron], folic acid 0.8 mg, vitamin C 75 mg) orally once daily.

Dosage form	CAPSULE
Renal impairment	Not required for iron supplementation; monitor iron levels in severe renal impairment (GFR <15 mL/min) due to risk of iron overload.
Liver impairment	No adjustment needed for iron; folic acid may require monitoring in severe hepatic impairment (Child-Pugh class C) due to altered folate metabolism.
Pediatric use	Not recommended for children under 12 years. For adolescents 12+, same as adult dose (1 tablet daily).
Geriatric use	No specific dose adjustment; monitor for constipation and iron overload, especially in patients with chronic disease or reduced clearance.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for FOLVRON (FOLVRON).

Breastfeeding	Cyanocobalamin and folic acid are excreted into breast milk in amounts that are not harmful to the nursing infant. Both are normal components of human milk. M/P ratio not available; however, supplementation is considered compatible with breastfeeding.
Teratogenic Risk	FOLVRON contains cyanocobalamin and folic acid. Both are essential for fetal development and are generally considered safe during pregnancy. There is no evidence of teratogenicity at recommended doses. However, high doses of folic acid ( >1 mg/day) may mask vitamin B12 deficiency. No known fetal risks in any trimester when used appropriately.

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to any component; hemochromatosis; hemosiderosis; pernicious anemia (folic acid may mask vitamin B12 deficiency); patients receiving repeated blood transfusions.