Is intravenous (IV) iron contraindicated in urinary tract infections (UTI)?

IV Iron Is Contraindicated in Active Urinary Tract Infections

Intravenous (IV) iron should not be administered during active urinary tract infections as it may promote bacterial growth, impair host immune function, and potentially worsen existing infections. 1

Pathophysiology of Iron in Infections

Iron plays a critical role in both host immunity and bacterial pathogenicity:

• Free iron serves as an essential nutrient for bacterial growth and can convert benign bacterial colonization into virulent infection 1
• Common uropathogens like Escherichia coli require iron for survival and persistence in the urinary tract 2
• IV iron administration increases levels of circulating non-transferrin-bound iron, which can be utilized by pathogens 3
• Iron can impair host immune function, particularly T-cell and neutrophil activity 1

Evidence Supporting Contraindication

Multiple guidelines and research support avoiding IV iron during active infections:

• The Kidney Disease: Improving Global Outcomes (KDIGO) and British Society of Gastroenterology guidelines explicitly recommend suspending or avoiding IV iron during active infections 1
• A large systematic review and meta-analysis of 154 RCTs (32,762 participants) found that IV iron was associated with a 16% increased risk of infection compared to oral iron or no iron (RR 1.16; 95% CI 1.03-1.29) 3
• Animal studies have demonstrated that dietary restriction of iron availability attenuates uropathogenic E. coli pathogenesis in urinary tract infections 2

Management Recommendations

When both iron supplementation and treatment for UTI are needed:

1. Complete antibiotic course first: Treat the UTI completely before administering IV iron 1
2. Confirm infection resolution: Ensure clinical and laboratory signs of infection have resolved 1
3. Consider alternatives during infection:
   • For non-urgent cases: Consider oral iron supplementation 1
   • For urgent cases requiring iron: Consider erythropoiesis-stimulating agents (ESAs) with minimal IV iron 1

Special Considerations

• Timing: The American College of Hematology recommends avoiding concurrent administration of IV iron and antibiotics due to potential interference with antibiotic efficacy 1
• Patient populations: Special attention should be given to patients with chronic kidney disease or inflammatory conditions who frequently require both iron supplementation and antibiotics 1

Common Pitfalls to Avoid

• Overlooking subclinical infections: Ensure complete resolution of UTI before IV iron administration, as subclinical infection may still be present despite symptom improvement
• Ignoring iron status: While avoiding IV iron during active infection is important, addressing iron deficiency after infection resolution remains necessary for optimal patient outcomes
• Assuming all iron preparations carry equal risk: While all IV iron preparations should be avoided during active infection, different preparations may have varying risk profiles 3

In conclusion, the evidence strongly supports withholding IV iron during active UTIs due to the increased risk of worsening infection and potential interference with antibiotic efficacy. Treatment of the infection should take priority, with iron supplementation resumed only after complete resolution of the infection.