FERROUS FUMARATE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FERROUS FUMARATE (FERROUS FUMARATE).
Iron is an essential component of hemoglobin, myoglobin, and various enzymes; ferrous fumarate provides elemental iron for erythropoiesis and oxygen transport.
| Metabolism | Absorbed in duodenum and proximal jejunum; transported via transferrin; stored as ferritin and hemosiderin; no significant hepatic metabolism. |
| Excretion | Primarily fecal (about 90%) as unabsorbed iron; minor renal excretion (<1%) via sloughed intestinal cells and bile; negligible urinary elimination. |
| Half-life | 5-7 hours for iron in serum after absorption; terminal half-life of storage iron (ferritin) is approximately 6 days; clinical context: follows first-order kinetics with iron recycling. |
| Protein binding | 99.5% bound to transferrin (iron transport) and ferritin (storage); minor binding to hemosiderin. |
| Volume of Distribution | 3-6 L/kg for total body iron (including storage); clinical meaning: extensive distribution into tissues (liver, spleen, bone marrow) as ferritin and hemosiderin. |
| Bioavailability | Oral: 10-20% from ferrous fumarate; increased with ascorbic acid or empty stomach; decreased with food (by 50-60%). |
| Onset of Action | Oral: Reticulocytosis begins in 3-7 days; hemoglobin rise starts at 2 weeks; peak effect at 4-6 weeks. |
| Duration of Action | Oral: Duration depends on iron stores; treatment typically 3-6 months to replenish stores; continuous effect while therapy continues. |
Oral: 200 mg (equivalent to 65 mg elemental iron) three times daily. Adults: 325 mg (106 mg elemental iron) one to three times daily.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required. Use with caution in chronic kidney disease due to potential iron overload; monitor iron stores. |
| Liver impairment | No specific dose adjustment. Avoid in severe hepatic impairment (Child-Pugh class C) due to risk of iron overload and impaired iron metabolism. |
| Pediatric use | Children 1-12 years: 3-6 mg/kg/day elemental iron in divided doses. Infants: 1-2 mg/kg/day elemental iron. Maximum: 15 mg/day for children <20 kg. |
| Geriatric use | Start at lower end of dosing range (e.g., 200 mg ferrous fumarate once daily) due to increased risk of constipation and GI intolerance. Monitor iron status regularly. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for FERROUS FUMARATE (FERROUS FUMARATE).
| Breastfeeding | Excreted in breast milk in low amounts; M/P ratio approximately 0.04-0.10. Considered compatible with breastfeeding; monitor infant for gastrointestinal effects. |
| Teratogenic Risk | No evidence of teratogenicity in first trimester. Fetal iron overload possible with excessive maternal dosing in second and third trimesters. |
| Fetal Monitoring | Monitor maternal hemoglobin, hematocrit, ferritin, and iron studies. Assess for gastrointestinal side effects and constipation. Fetal monitoring for iron overload only in cases of maternal overdose. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hemochromatosis","Hemosiderosis","Hemolytic anemias","Repeated blood transfusions","Known hypersensitivity to ferrous fumarate"]
| Precautions | ["Accidental overdose may cause fatal poisoning in children","Risk of iron overload in hemochromatosis or chronic hemolytic anemias","GI irritation, constipation, dark stools","May exacerbate peptic ulcer disease or ulcerative colitis"] |
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| Fertility Effects | No known adverse effects on fertility. Iron deficiency anemia may impair fertility; correction may improve reproductive outcomes. |