AURYXIA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for AURYXIA (AURYXIA).
AURYXIA (ferric citrate) is a phosphate binder that reduces serum phosphate by binding dietary phosphate in the gastrointestinal tract, forming insoluble ferric phosphate complexes that are excreted in the feces. The iron component also increases serum iron parameters and may improve iron stores.
| Metabolism | Ferric citrate is minimally absorbed. The absorbed iron is processed via normal iron metabolism pathways (e.g., incorporation into hemoglobin, storage as ferritin). No significant hepatic metabolism; the drug acts locally in the GI tract. |
| Excretion | Primarily fecal as unabsorbed drug (≥99%). Renal excretion is negligible (<1%). |
| Half-life | Not applicable; systemic absorption is minimal. AURYXIA is not absorbed and acts locally in the GI tract. |
| Protein binding | Not applicable (not systemically absorbed). |
| Volume of Distribution | Not applicable (negligible systemic absorption; Vd not measurable). |
| Bioavailability | Negligible (<0.1% absorbed). |
| Onset of Action | Not applicable; clinical effect on serum phosphorus occurs over days to weeks with chronic dosing. |
| Duration of Action | Not applicable; effect persists while drug is present in the gut lumen. Once discontinued, serum phosphorus returns to baseline within days. |
Adult: 1 tablet (1700 mg ferric citrate) three times daily with meals, titrated every 2-4 weeks to achieve target serum phosphate levels. Maximum dose: 12 tablets per day.
| Dosage form | TABLET |
| Renal impairment | No dosage adjustment required for renal impairment; monitor serum phosphate and iron parameters. |
| Liver impairment | No specific hepatic adjustment; caution in severe impairment due to potential iron overload. |
| Pediatric use | Safety and efficacy not established in pediatric patients. |
| Geriatric use | No specific geriatric dose adjustment; consider comorbidities and polypharmacy. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for AURYXIA (AURYXIA).
| Breastfeeding | Unknown if excreted in human milk; M/P ratio not established. Due to potential for iron overload in infant, breastfeeding not recommended during therapy. |
| Teratogenic Risk | Category B: No evidence of risk in humans based on animal studies; insufficient human data in pregnant women. No known fetal abnormalities reported in first trimester; no specific risks documented in second or third trimester. Use only if clearly needed. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to ferric citrate or any components of the formulation.","Iron overload disorders (e.g., hemochromatosis).","Concurrent use with oral iron supplements (due to risk of iron overload)."]
| Precautions | ["Risk of iron overload, especially in patients with hemosiderosis or hemochromatosis.","Monitor serum ferritin and transferrin saturation to avoid iron toxicity.","May increase serum calcium and cause metabolic alkalosis due to citrate component.","Gastrointestinal adverse effects (e.g., discolored stools, constipation, diarrhea).","Accidental overdose may cause acute iron toxicity, especially in children."] |
| Food/Dietary | Take with food to maximize phosphate binding. Avoid high-phosphate foods (e.g., dairy, nuts, organ meats) to reduce phosphate load. No specific drug-food interactions beyond phosphate content. |
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| Monitor serum ferritin, transferrin saturation, and hemoglobin periodically; avoid iron overload. Monitor maternal blood pressure and renal function if underlying CKD. Fetal monitoring per routine obstetric care. |
| Fertility Effects | No known effects on fertility in animal studies; human data not available. No impairment of fertility observed in reproductive studies. |
| Clinical Pearls | AURYXIA (ferric citrate) is a phosphate binder that also serves as an iron source. Monitor serum ferritin and transferrin saturation regularly due to risk of iron overload, especially in patients with chronic kidney disease (CKD) not on dialysis. Do not use in patients with iron overload syndromes (e.g., hemochromatosis). Separate administration from oral iron supplements by at least 2 hours due to competition for absorption. Can cause discoloration of stool (black/dark). |
| Patient Advice | Take with meals as directed to bind dietary phosphate. · Swallow tablets whole; do not crush or chew. · Expect dark or black stools, which is normal; report persistent gastrointestinal issues. · Adhere to dietary phosphate restrictions for optimal control. · Inform your doctor if you have a history of iron overload or gastrointestinal disorders. · Do not take with oral iron supplements; separate by at least 2 hours. |