Can Iron Infusions Cause Red-Orange Urine?
No, iron infusions do not typically cause red-orange urine discoloration. This is not a recognized or documented adverse effect of intravenous iron therapy in any of the major clinical guidelines or safety monitoring protocols.
Known Adverse Effects of IV Iron
The well-established adverse effects of intravenous iron therapy include 1:
- Infusion reactions (hypersensitivity-type reactions occurring in approximately 0.5% of patients) 1
- Complement-activated related pseudo-allergy (CARPA), also known as Fishbane reactions, which are the most common infusion reactions but are physiologically different from true anaphylaxis 1
- True anaphylaxis (exceedingly rare, occurring in <1:200,000 administrations) 1, 2
- Hypophosphatemia (particularly with ferric carboxymaltose at 58%, compared to 4% with iron derisomaltose and 1% with iron sucrose) 1, 2
- Acute symptoms including hypotension, flushing, loin pain, and upper gastric pain 1
- Delayed reactions such as arthralgias and myalgias (dose-related, rarely occurring with doses ≤100 mg) 1
Oxidative Stress and Renal Effects
While IV iron can cause transient renal effects, these manifest as proteinuria and enzymuria rather than urine discoloration 3, 4:
- Intravenous iron produces oxidative stress associated with transient proteinuria and tubular damage 4
- These effects are temporary and typically resolve within 24 hours 4
- Urinary markers include increased albumin excretion and enzyme excretion (N-acetyl-beta-glucosaminidase), not color changes 3
Important Clinical Distinction
Red-orange urine is NOT listed in any comprehensive safety monitoring protocols for IV iron administration 1, 2. The 2024 expert consensus guidelines on IV iron administration provide detailed guidance on pre-infusion assessment, monitoring, and management of reactions, but urine discoloration is conspicuously absent from these comprehensive safety considerations 1.
What to Consider Instead
If a patient develops red-orange urine after iron infusion, alternative explanations should be investigated:
- Hematuria from other causes (urinary tract infection, kidney stones, bladder pathology)
- Hemoglobinuria or myoglobinuria from unrelated conditions
- Medication effects from other drugs the patient may be taking
- Dietary factors (certain foods, supplements, or dyes)
The absence of urine discoloration from all major guidelines 1, 2, 5 and safety literature strongly indicates this is not a recognized effect of IV iron therapy.