Intravenous (IV) iron is a treatment that delivers iron directly into the bloodstream. It is used for individuals with iron-deficiency anemia when oral supplements are ineffective or cannot be tolerated. This method allows for a much faster correction of iron levels than pills. While an established medical procedure, IV iron administration is linked to a potential for infection.
The Biological Link Between Iron and Infection
The connection between iron and infection is biological. Many harmful bacteria, like Staphylococcus aureus, depend on iron to grow and replicate. The human body has natural mechanisms to keep iron tightly controlled and bound to proteins like transferrin, partly to withhold it from invading microbes. This process is known as nutritional immunity.
An IV iron infusion delivers a large amount of the mineral into circulation, which can temporarily overwhelm the body’s iron-binding capacity. This leads to a spike in “non-transferrin-bound iron,” a form of free iron that is easily accessible to pathogens. This abundance of a nutrient can act like a fertilizer for bacteria, potentially fueling a new infection or worsening a pre-existing one. Studies show the actual increase in infection risk is relatively modest.
A large 2021 meta-analysis of 154 clinical trials found that IV iron was associated with a slightly increased risk of infection compared to oral iron or no iron. This risk must be balanced against the benefits of treating anemia, such as reducing the need for blood transfusions. The specific type of bacteria can also play a role, as some have developed mechanisms to acquire iron.
Identifying Potential Infection Symptoms
It is important for patients to distinguish between common, temporary side effects of an iron infusion and the signs of an infection. Many people experience mild, short-lived reactions to the infusion itself. These can include headache, dizziness, muscle aches, or a metallic taste, which typically resolve within a day or two.
In contrast, the symptoms of a systemic infection are more persistent and severe. An indicator is a high fever that does not subside, often accompanied by a rapid heart rate or confusion. Signs of a localized infection at the IV insertion site include increasing redness, swelling, pain, or pus. These symptoms warrant immediate medical attention.
Some side effects can overlap, which may cause confusion. For example, both an infusion reaction and an infection can cause chills and a low-grade fever. The main difference is the duration and severity of the symptoms. Infusion reactions fade quickly, whereas signs of infection persist or worsen over time.
Populations at Higher Risk
Certain patient groups have a greater susceptibility to infections following IV iron therapy. Individuals with chronic kidney disease, particularly those undergoing hemodialysis, are one such group. Their frequent need for vascular access provides a direct route for bacteria to enter the bloodstream, and the underlying disease can also affect immune function.
Patients with compromised immune systems are also at an elevated risk. This includes individuals with conditions like HIV, those undergoing chemotherapy, or organ transplant recipients on immunosuppressive drugs. Their body’s ability to fight off pathogens is already weakened, making the iron-fueled growth of bacteria a greater threat.
Another population of concern includes those with inflammatory bowel disease (IBD), such as Crohn’s disease or ulcerative colitis. One analysis found that patients with IBD had a higher risk of infection after receiving IV iron compared to other groups.
Safe Administration and Risk Reduction
Healthcare providers follow specific protocols to minimize infection risk. A primary step is screening patients for any signs of an active infection before scheduling the infusion. If a patient has a fever or other symptoms of illness, the procedure is typically delayed until they have recovered.
During the procedure, strict sterile techniques are followed. This involves cleaning the skin at the insertion site and using sterile equipment. The choice of iron formulation may also be a factor, as newer preparations are more stable and release iron more slowly, potentially reducing the amount of free iron in the blood.
Patients also have a role in reducing their risk. It is important to inform the medical team of any new symptoms or illnesses that develop prior to the scheduled infusion. After the procedure, keeping the IV insertion site clean and dry is important for preventing localized infections.