Ferric Ammonium Citrate 400 mg/5 ml Mixture

Introduction

Ferric ammonium citrate 400 mg/5 ml mixture (FAC syrup) is a commonly prescribed medication for prevention and treatment of iron-deficiency anaemia in premature infants at Malaysia.

• FAC mixture is commonly supplied for 3-4 months post discharge or until next review.

Extemporaneous Formulation (BPC 1973, page 742)

Ferric ammonium citrate BP 80 g

Compound orange spirit BP 2 ml

Syrup BP 100 ml

Double strength chloroform water BP 500 ml

Water q.s. to 1000 ml.

* This product would be recently prepared as double strength chloroform water BP acts as a preservative and therefore would attract a four-week discard date.

* The dose should be taken well diluted with water.

Dosage Calculation

Dosing of FAC syrup is based on elemental iron needed per day. As per Frank Shann Drug Doses, 2017, ferrous salts dosage is as below:

• Prophylaxis, 2 mg/kg/day elemental iron oral
• Treatment, 6 mg/kg/day elemental iron oral.

* In real practice, the dosing prescribed can be within the range of 2-6 mg/kg/day elemental iron.

To calculate the volume of FAC syrup needed, you should know the elemental iron content in Ferric Ammonium Citrate 400 mg/5 ml syrup.

• As written in page 97 of Paediatric Protocols for Malaysian Hospitals, 4th Edition, 2019), it contains 86 mg/5 ml of elemental iron.

The estimation of 86 mg elemental iron per 5 ml is probably based on ratio of molar mass.

• Ferric ammonium citrate(C6H8FeNO7), molar mass 261.98 g/mol
• Iron molar mass 55.845 g/mol
• Hence 400 * (55.845/261.98) = 85.266

NOTE: Once a provisional registered pharmacist asked me a question that I do not have a final answer till today: In Martindale, it states that USP 42 (Ferric Ammonium Citrate): It contains between 16.5% and 18.5% of iron. Hence, by this estimation, should not FAC 400 mg/5 ml syrup has less than 86 mg/5 ml of elemental iron content?

Calculation Example

For a baby weighing 2.1 kg, having a target dose of 6 mg/kg/day of elemental iron,

Elemental iron needed = 2.1 kg * 6 mg/kg/day = 12.6 mg

Volume of Ferric Ammonium Citrate Mixture = 12.6 mg / 86 mg * 5 ml = 0.73 ml

The Alternative

There is currently no commercially available ferric ammonium citrate 400 mg/5 ml mixture in the Malaysia market.

A possible alternative source of elemental iron will be Maltofer (iron (III)-hydroxide polymaltose complex).

• Maltofer + folic acid chewable tablet: 100 mg elemental iron and 0.35 mg folic acid per tablet
• Maltofer drops: 2.5 mg elemental iron per drop
• Maltofer syrups: 10 mg element iron per ml syrup

NOTE: Iron polymaltose is absorbed best if taken during or immediately after a meal.