FERRIC CITRATE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FERRIC CITRATE (FERRIC CITRATE).
Ferric citrate dissociates to provide ferric iron, which binds dietary phosphate in the gastrointestinal tract, forming insoluble ferric phosphate that is excreted in feces, thereby reducing serum phosphate levels. It also provides iron for erythropoiesis.
| Metabolism | Not metabolized; iron is absorbed and incorporated into hemoglobin or stored as ferritin; phosphate-bound iron is excreted unchanged in feces. |
| Excretion | Primarily fecal as unabsorbed iron (≥90%); minimal renal excretion (<1%) of absorbed iron. |
| Half-life | Approximately 6 hours for absorbed iron; clinical effect on serum phosphate occurs within 1–2 weeks. |
| Protein binding | Absorbed iron is extensively bound to transferrin (≈99.9%); unbound iron is minimal. |
| Volume of Distribution | 2–5 L/kg for absorbed iron, reflecting distribution into reticuloendothelial system and erythroid precursors. |
| Bioavailability | Oral: Very low (1–5%) due to limited absorption and active efflux; absorption increases with iron deficiency. |
| Onset of Action | Oral: Reduction in serum phosphate observed within 1 week; maximal effect by 4–6 weeks. |
| Duration of Action | Duration of phosphate-binding effect is approximately 24 hours with thrice-daily dosing; clinical effect persists as long as therapy continues. |
1-2 tablets (210-420 mg elemental iron) orally three times daily with meals.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for chronic kidney disease; contraindicated if GFR <30 mL/min/1.73 m² due to risk of iron overload. |
| Liver impairment | No dose adjustment recommended for hepatic impairment; use with caution in severe Child-Pugh C. |
| Pediatric use | Not recommended for children <6 years; for children ≥6 years: 1 tablet (210 mg elemental iron) orally three times daily with meals. |
| Geriatric use | No specific dose adjustment; monitor for gastrointestinal adverse effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for FERRIC CITRATE (FERRIC CITRATE).
| Breastfeeding | Ferric citrate is poorly absorbed, but iron excreted in breast milk is minimal. M/P ratio not established. Considered compatible with breastfeeding; monitor infant for gastrointestinal effects. |
| Teratogenic Risk | No human data; animal studies not available. Iron is essential for fetal development; however, excessive iron may be harmful. Risk cannot be excluded; use only if clearly needed. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
["Patients with iron overload syndromes (e.g., hemochromatosis)","Hypersensitivity to ferric citrate or any component of the formulation"]
| Precautions | ["Risk of iron overload, especially in patients with serum ferritin >500 ng/mL or transferrin saturation >50%","May increase serum calcium due to reduced phosphate binding of calcium","Gastrointestinal adverse reactions including diarrhea, constipation, nausea, and vomiting","Potential for aluminum absorption if taken with aluminum-containing antacids"] |
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| Monitor maternal hemoglobin, serum ferritin, and iron indices (total iron-binding capacity, transferrin saturation) periodically. Assess for signs of iron overload or deficiency. No specific fetal monitoring required. |
| Fertility Effects | No known adverse effects on fertility. Iron deficiency may impair fertility; supplementation may improve outcomes. No data on direct effects of ferric citrate. |