Ferrous sulfate with ascorbic acid
Brand names: Ferrograd C
This fixed combination of ferrous sulfate with ascorbic acid (vitamin C) is an oral preparation for treating and preventing iron-deficiency anaemia.
Adult dose
Paediatric dose
Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.
Contraindications
- §4.3 verbatim: 'Intestinal diverticular disease or any intestinal obstruction.'
- §4.3 verbatim: 'Iron preparations are contra-indicated in patients with haemochromatosis and haemosiderosis.'
- §4.3 verbatim: 'Iron is contra-indicated in patients receiving repeated blood transfusions.'
- §4.3 verbatim: 'Oral iron preparations are contra-indicated when used concomitantly with parenteral iron therapy.'
Side effects
- §4.8 verbatim: 'Side-effects reported are similar to those associated with conventional oral iron preparations, i.e. nausea, vomiting, abdominal pain or discomfort, blackening of stools, diarrhoea and/or constipation, but the incidence of side-effects is less owing to the prolonged release nature of the formulation.'
- Frequency not known, §4.8 gastrointestinal disorders: nausea; vomiting; abdominal pain or discomfort; blackening of stools; diarrhoea and/or constipation.
- Frequency not known, §4.8: mouth ulceration 'in the context of incorrect administration, when the tablets are chewed, sucked or kept in mouth'.
- §4.8: 'Elderly patients and patients with deglutition disorders may also be at risk of oesophageal lesions or of bronchial necrosis, in case of false route'.
- §4.8: bronchial stenosis (see §4.4 — aspiration of iron sulfate tablets can cause necrosis of the bronchial mucosa, presenting as coughing, haemoptysis, bronchostenosis and/or pulmonary infection, potentially days to months after the aspiration).
- §4.8: 'Isolated cases of allergic reaction have been reported ranging from rash to anaphylaxis.'
- §4.8, ascorbic acid component: 'Ascorbic acid is usually well tolerated. However, large doses are reported to cause diarrhoea and other gastrointestinal disturbances and are associated with the formation of renal calcium oxalate calculi.'
Monitoring
- §4.4 verbatim: 'Iron preparations colour the faeces black, which may interfere with tests used for detection of occult blood in the stools. The guaiac test occasionally yields false positive tests for blood.' Interpret faecal occult blood results with this in mind.
- §4.4: before prescribing to an elderly patient or anyone with swallowing difficulty, carry out 'a careful evaluation of the individual patient's risk of aspiration' and consider an alternative formulation. 'Patients should seek medical attention in case of suspected aspiration.'
- §4.4: use with caution where intestinal transit is delayed — the prolonged-release tablet's inert plastic matrix 'may cause a safety hazard' in such patients.
- §4.5: review co-prescribed tetracyclines, quinolones, penicillamine, antacids, calcium, magnesium trisilicate, trientine and zinc salts for absorption interference in both directions, and separate the doses as the SPC specifies.
Clinical monograph
How it works
Ferrous sulfate provides absorbable iron[II] for haemoglobin synthesis, while ascorbic acid acts as a reducing agent that helps keep iron in the ferrous state and may modestly enhance its intestinal absorption.
Prescribing in practice
- As with all iron products, accidental overdose is dangerous and potentially fatal in children, so secure storage out of reach is the priority safety point.
- The same absorption interactions apply as for plain ferrous sulfate, requiring separation from tea, antacids, calcium and chelated drugs such as quinolones, tetracyclines and levothyroxine.
- The added ascorbic acid offers only a modest absorption benefit and does not reduce the gastrointestinal side effects typical of oral iron.
Monitoring
Reassess haemoglobin and iron indices after several weeks, continuing treatment beyond normalisation to replenish stores.
Counselling the patient
- Black stools are normal with this iron-containing product.
- Keep away from children because of the risk of serious overdose.
- Avoid taking with tea, milk or indigestion remedies at the same time.
Evidence & guidelines
Oral ferrous salts are first-line for iron-deficiency anaemia per NICE; the contribution of added vitamin C to absorption in practice is generally regarded as small.
Reference: Confirm identity and dosing against the manufacturer SPC (eMC) and NICE. Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).
Related
Curated clinical cross-links plus same-class fallbacks.
- DOAC Score for Selecting Direct Oral Anticoagulant in Non-Valvular AF · Anticoagulation
- Corrected Reticulocyte Count / Reticulocyte Production Index · Anaemia
- Ganzoni Equation for Iron Deficiency · Anaemia
- Transferrin Saturation Calculator · Anaemia / Iron Studies
- Tumor Lysis Syndrome (Cairo-Bishop Criteria) · Oncological Emergency
- Iron Deficiency Anaemia Calculator · Anaemia Assessment
- Major Haemorrhage / Massive Transfusion · BCSH; RCOA; RCEM; RCS — BCSH Guidelines
- Anaemia Investigation · BSH / NICE
- Splenomegaly Workup · BSH; BMJ Best Practice
- Deep Vein Thrombosis Diagnosis and Treatment · NICE CG144 / NICE NG158
- Sickle Cell Crisis · BSH 2021 / BCSH
- Neutropenic Sepsis · NICE CG151 2012 / ESMO