Ferric citrate (Auryxia) has a dual mechanism of action. It provides iron in the ferric form that is used in hemoglobin synthesis after it is absorbed into the bloodstream. It also binds to dietary phosphate and inhibits its absorption. Thus, it is used to lower serum phosphate levels especially in patients with chronic kidney disease who are on hemodialysis and is also used to treat iron-deficiency anemia in patients with kidney disease who are not on hemodialysis.

Ferric citrate (Auryxia) Uses:

• Hyperphosphatemia:

  • It is indicated for the treatment and prevention of high phosphate levels in the blood in patients with chronic kidney disease who are on hemodialysis.

• Iron deficiency anemia:

  • It is indicated for the treatment of iron deficiency anemia in patients with chronic kidney disease who are not on hemodialysis.

Ferric citrate (Auryxia) Dose in Adults

Note:

• Each 1 gm tablet of ferric citrate contains 210 mg of ferric iron.

Ferric citrate (Auryxia) Dose in the treatment of Hyperphosphatemia: Oral:

• Initially, two tablets (420 mg ferric iron) thrice daily.
• Maintenance Dose:
  • The dose is increased at weekly intervals or longer by 210 mg (one tablet) or 420 mg (two tablets) as required to achieve the target serum phosphate levels.
  • The maximum daily dose is 2520 mg of ferric iron or 12 tablets.

Ferric citrate (Auryxia) Dose in the treatment of Iron deficiency anemia in non-dialysis CKD Patients:

• One tablet equivalent to ferric iron of 210 mg is taken orally thrice daily.
• The dose is titrated to achieve the target hemoglobin.
• The maximum daily dose is 2520 mg of ferric iron or 12 tablets.
• Note:
  • Dose titration may be considered if the serum phosphorus levels exceed 3 mg/dl.
  • Treatment may be discontinued if the serum phosphorus levels are less than 2 mg/dl.
  • If the serum phosphate level is between 2 to 2.5 mg/dl, the dose may be reduced.

Use in Children:

Not indicated.

Ferric citrate (Auryxia) Pregnancy Risk Category: N (Not assigned)

• The drug has not been studied in animal or human pregnancy studies.
• During pregnancy, maternal iron requirements increase, however, fetal iron is maintained at fairly adequate levels even in mild to moderate iron deficiency in the mother.
• In severe cases of maternal iron deficiency, fetal iron levels may drop and may be associated with adverse outcomes that include:
  • low birth weight
  • preterm birth, and
  • increased perinatal mortality.
• Iron deficiency in pregnant and non-pregnant females is treated the same. Oral iron is sufficient, however, in females with severe iron deficiency, where a rapid increase in the hemoglobin is required, and in patients with malabsorption or another gastrointestinal disease, parenteral iron may be given (iron sucrose or venofer).
• Iron overload in pregnant females should also be avoided as it can cause fetal malformations, abortions, and gestational diabetes.

Ferric citrate use during breastfeeding:

• Iron is present in breastmilk. Iron concentration in the breastmilk is dependent on the maternal iron content.
• Usually, iron levels are maintained at fairly adequate levels except in severe maternal iron deficiency anemia.
• The manufacturer recommends using ferric citrate with caution in lactating mothers weighing the risks and benefits to the nursing infant and the mother respectively.
• Other iron preparations may be used.

Dose in Kidney Disease:

No dosage adjustment is necessary in patients with kidney disease.

Dose in Liver disease:

In the manufacturer's labeling, adjustments in the dose have not been provided in patients with liver disease.

Common Side Effects of Ferric citrate (Auryxia):

• Gastrointestinal:

  • Darkening of stools
  • Diarrhea
  • Constipation
  • Nausea

Less Common Side Effects of Ferric citrate (Auryxia):

• Endocrine & metabolic:

  • Hyperkalemia

• Gastrointestinal:

  • Vomiting
  • Abdominal pain

• Respiratory:

  • Cough

Contraindications to Ferric citrate (Auryxia):

It is contraindicated in iron overload syndromes such as hemochromatosis and hemolytic anemias.

Warnings and Precautions

• Iron toxicity:

  • Overdosing and treatment for prolonged periods may result in iron toxicity.
  • Patients may have elevated serum iron, ferritin, and transferrin saturation.
  • Iron studies should be monitored at baseline and periodically thereafter during therapy.

• Stool discoloration:

  • Patients must be counseled that their stool color may change due to the iron content and should not be considered pathological.

Monitoring parameters:

• Serum iron, serum ferritin, and transferrin saturation (TSAT) before treatment initiation and during the treatment.
• Also, monitor serum phosphate at regular intervals.

Ferric citrate: Drug Interaction

Note: Drug Interaction Categories:

• Risk Factor C: Monitor When Using Combination
• Risk Factor D: Consider Treatment Modification
• Risk Factor X: Avoid Concomitant Use

How to administer Ferric citrate (Auryxia)?

• It is administered with meals.
• The tablets should not be crushed, chewed, or broken as it may discolor the teeth and oral cavity.

Mechanism of action of Ferric citrate (Auryxia):

Hyperphosphatemia:

• It binds to dietary phosphate in the gastrointestinal tract and forms ferric phosphate.
• Ferric phosphate is insoluble and is excreted in the stools. Thus, it lowers serum phosphate by acting as a phosphate binder.

Iron deficiency anemia:

• Ferric iron is absorbed and transported via the enterocytes into the blood.
• It is then carried by transferrin and incorporated into hemoglobin.

International Brand Names of Ferric citrate:

• Auryxia
• Riona

Ferric citrate Brand Names in Pakistan:

No Brands Available in Pakistan.