What medications affect iron absorption?

From the Guidelines

Medications such as proton pump inhibitors, H2 blockers, antacids, tetracycline antibiotics, quinolones, and levodopa can significantly affect iron absorption, and patients should be advised to take iron supplements at least 2 hours before or 4 hours after these medications to minimize interactions. Several factors can affect iron absorption, including dietary components and medications. According to a recent study 1, tea and coffee are powerful inhibitors of iron absorption and should not be consumed within an hour after taking iron.

Key Factors Affecting Iron Absorption

• Medications: proton pump inhibitors, H2 blockers, antacids, tetracycline antibiotics, quinolones, and levodopa
• Dietary components: tea, coffee, calcium supplements, dairy products, and high-fiber foods
• Timing of iron supplementation: take iron supplements at least 2 hours before or 4 hours after medications that may interact with iron absorption

Recommendations for Optimal Iron Absorption

• Take iron supplements with vitamin C-rich foods or orange juice to enhance absorption
• Avoid taking iron with calcium supplements, dairy products, coffee, tea, or high-fiber foods
• Consider taking iron supplements at bedtime to minimize interactions with other medications
• Regular monitoring of iron levels may be necessary for patients on long-term medications that affect iron absorption, as suggested by a study on anemia of chronic kidney disease 1.

From the FDA Drug Label

Carbidopa and levodopa orally disintegrating tablets and iron salts or multivitamins containing iron salts should be coadministered with caution. Iron salts can form chelates with levodopa and carbidopa and consequently reduce the bioavailability of carbidopa and levodopa

• Medications that affect iron absorption are not directly mentioned, but it is stated that iron salts can reduce the bioavailability of levodopa and carbidopa.
• The medication that is affected by iron is levodopa, as iron salts can form chelates with it and reduce its bioavailability.
• Iron salts or multivitamins containing iron salts should be coadministered with caution when taking carbidopa and levodopa orally disintegrating tablets 2

From the Research

Medications Affecting Iron Absorption

• Proton pump inhibitors (PPIs) have been associated with decreased iron absorption, as they reduce gastric acidity, which is necessary for optimal iron absorption 3, 4, 5, 6.
• Histamine-2 receptor antagonists may also affect iron absorption, although the evidence is limited 3.
• Calcium carbonate, an antacid, can inhibit iron absorption 3.
• The use of antacids along with oral ferrous sulfate supplementation may not affect the absorption of iron in some cases 7.

Specific Medications and Their Effects

• Omeprazole, a PPI, has been shown to decrease the absorption of oral iron supplementation, leading to suboptimal response to iron therapy 4.
• Ranitidine, an H2 receptor antagonist, may also affect iron absorption, although the evidence is limited 7.
• Proton pump inhibitors, in general, have been associated with iron deficiency anemia, particularly in patients with no other underlying conditions that predispose to iron deficiency 3, 5, 6.

Patient Response to Medications

• Patients taking PPIs may require higher doses of iron or longer treatment durations to achieve optimal iron levels 4, 5.
• Intravenous iron therapy may be necessary for patients with iron deficiency anemia who are taking PPIs 5.
• The response to iron therapy may vary depending on the patient's age, with older patients potentially having a suboptimal response to iron therapy while taking PPIs 4.