Desferrioxamine

Why this drug is interesting

Iron poisoning is the classic deceptive overdose. The initial gastrointestinal phase — vomiting, diarrhoea, abdominal pain, sometimes haematemesis — is followed by an apparent recovery of several hours, then by shock, profound metabolic acidosis, hepatic failure and coagulopathy. The quiet middle phase is where patients get discharged.

Desferrioxamine is the only chelator for it, and it is one of the few antidotes whose effect is visible at the bedside: the iron–chelator complex, ferrioxamine, is excreted in the urine and turns it a reddish-brown that the older literature calls vin rosé.

Pharmacology

Mechanism

Desferrioxamine is derived from a bacterial siderophore — a molecule evolved specifically to scavenge iron from the environment. It is hexadentate, wrapping six coordination bonds around a single ferric ion to form ferrioxamine, a stable, water-soluble complex cleared by the kidney.

Iron poisoning kills through free iron catalysing oxidative damage, uncoupling oxidative phosphorylation, and acting as a direct corrosive on gut mucosa. Chelation removes free and loosely bound iron; it does not remove iron already incorporated into haemoglobin or cytochromes, which is why it does not cause anaemia.

Elimination

Ferrioxamine is renally excreted, which is the origin of the urine colour change. Both desferrioxamine and its iron complex are dialysable, which matters in anuric patients.

Dosing in acute iron poisoning

Intravenous — the route to use

The label ties the rate, the reduction and the ceiling together in one sentence: intravenous administration "is the preferred route and the recommended rate for infusion is 15 mg/kg per hour and should be reduced as soon as the situation permits, usually after 4 to 6 hours, so that the total intravenous dose does not exceed a recommended 80 mg/kg in any 24 hour period".¹

Intramuscular

2 g for an adult, 1 g for a child, usually as a single injection.¹ This is a fallback where intravenous access is unavailable — it is not the preferred route in significant poisoning, where a titratable infusion is what you want.

Endpoints

Chelation is generally continued until the patient is clinically well, the acidosis has resolved and the urine colour has normalised, guided by serial serum iron and clinical state. The UK operational endpoints are on TOXBASE — the appended prescribing information gives the rate and the ceiling but no stopping rule for acute poisoning.

Safety

Infusion-rate effects

The label states it directly: "Treatment with Desferal by the intravenous route should only be administered in the form of slow infusions. Rapid intravenous infusion may lead to hypotension and shock (e.g. flushing, tachycardia, collapse and urticaria)."¹ The patient-facing section puts low blood pressure at up to 1 in 1,000, noting that "this can happen if Desferal is not given correctly". Separately, hypotension, rash, itching, breathing difficulty and facial or throat swelling are listed as features of a very rare allergic reaction (fewer than 1 in 10,000), and bronchospasm with wheeze and cough as a reason to stop and seek help immediately.¹

Prolonged infusion

Sensory toxicity

Ototoxicity and ocular toxicity are dose- and duration-related and belong mainly to chronic overload therapy, but they are real: the PIL reports tinnitus and deafness in up to 1 in 100, and in up to 1 in 1,000 blurred vision, impaired or lost vision, colour blindness and night blindness.¹ Long-term users have regular hearing and eye tests.

Infection

Interactions

Prochlorperazine

"Desferal should not be used in combination with prochlorperazine (a phenothiazine derivative) since prolonged unconsciousness may result."¹ That is a prohibition, not a caution — and prochlorperazine is exactly what a vomiting poisoned patient may be given.

Vitamin C

Dose-dependent, and the label's position is more specific than the usual teaching. Oral vitamin C up to 200 mg daily in divided doses may enhance excretion of the iron complex; larger doses add nothing. Above 500 mg daily, reversible impairment of cardiac function has been seen in severe chronic iron-storage disease, so it must not be given in cardiac failure, must not be started within the first month of Desferal therapy, and cardiac monitoring is indicated during combined therapy.¹ Note this guidance is written for chronic overload, not acute poisoning.

Erythropoietin

Desferrioxamine affects aluminium levels and may necessitate dose adjustment of erythropoietin if co-prescribed.¹

Gallium-67 imaging

Results may be distorted by rapid urinary excretion of Desferal-bound radiolabel; discontinue 48 hours before scintigraphy.¹

Other populations

• Children under 3 — growth retardation and bone changes are reported in this age group and growth should be monitored.¹
• Renal impairment and dialysis — convulsions have been reported mainly in dialysis patients.¹
• Pregnancy — flagged for immediate discussion in the PIL. Iron poisoning in pregnancy is treated; the risk of untreated maternal iron toxicity dominates.
• Very common local effects — injection site pain, swelling, redness, rash, itch or scabbing, and limb muscle or joint ache.¹

Practical use in the ED

1. Work out the elemental iron dose, not the tablet weight. Ferrous sulphate is about 20% elemental iron, ferrous fumarate about 33%, ferrous gluconate about 12%. Toxicity is conventionally described in mg/kg of elemental iron.
2. Take a serum iron at 4–6 hours post-ingestion, and repeat it if a modified-release preparation is involved or the picture is worsening.
3. Do not give activated charcoal. Consider an abdominal radiograph — radio-opaque tablets support both the diagnosis and a whole-bowel irrigation decision.
4. Resuscitate the acidosis and the shock. Iron poisoning kills through distributive and cardiogenic shock and hepatic failure, and desferrioxamine does not treat those directly.
5. Start desferrioxamine at 15 mg/kg/hour in significant poisoning, planning the reduction at 4–6 hours and tracking the running total against the 80 mg/kg/24 h ceiling.
6. Watch the urine. Vin rosé discolouration is the crude bedside marker that free iron is being chelated and excreted.
7. Call NPIS. Iron is a poisoning where the thresholds for chelation, the endpoint of chelation and the role of whole-bowel irrigation all warrant a conversation, and where paediatric and obstetric cases are commoner than average.

Critical appraisal

Desferrioxamine has never been tested against placebo in acute human iron poisoning and never will be. Its mechanism is unambiguous, its bedside marker of effect is visible, and its use is universal. What is genuinely uncertain is the threshold — which patients need chelation rather than supportive care and observation — and the endpoint. Both vary between sources, and neither is settled by the label, because in the UK there is effectively no accessible label.

The other honest caveat is that the ARDS and hypotension risks are label statements without quantified exposure thresholds. The label is clear on direction — excessive daily dose for ARDS, rapid infusion for hypotension — but does not define the exposure at which either occurs, and neither is supported by controlled data.

References

1. 1
   Desferal Vials 500 mg (desferrioxamine mesilate) — Patient Information Leaflet, Novartis Pharmaceuticals UK Ltd. electronic Medicines Compendium, product 3813 · PIL PDF. The PDF contains the patient leaflet and, from page 7, an appended prescribing-information section (Therapeutic Indications, Posology, Special warnings, Interactions, Undesirable effects). Source of the 15 mg/kg/hour rate and its stated purpose, the 4–6 hour reduction, the 80 mg/kg per 24 hour maximum, the intramuscular doses, the rapid-infusion hypotension warning, the excessive-dose ARDS warning, the Yersinia and mucormycosis warnings, the prochlorperazine prohibition, the vitamin C dosing and cardiac warnings, the erythropoietin and gallium-67 notes, the urine discolouration and the adverse-effect frequencies. The emc lists no SmPC document for this product (checked 4 September 2026). Note that /smpc/print and /pil/print both return HTTP 404 for product 3813, so a 404 on that path is not evidence either way — an earlier version of this page cited one as if it were.
2. 2
   Hoegberg LCG, Gosselin S, Buckley NA, Wood DM, et al. Recommendations from the Clinical Toxicology Recommendations Collaborative on the administration of activated charcoal in acute oral overdose. Clinical Toxicology 2026;64(6):419–475. PubMed 41906697. Table 4: iron carries a strong recommendation against single-dose, additional-dose and multiple-dose activated charcoal. Full text read 4 Sep 2026.
3. 3
   National Poisons Information Service. TOXBASE · NPIS 0344 892 0111. The authoritative UK source for iron poisoning thresholds, chelation indications and endpoints, in the absence of a published SmPC.