Gastrointestinal (GI) bleeding is a common side effect of taking aspirin. A person with aspirin-induced GI bleeding may not always have symptoms (like stomach pain) or obvious signs of blood in their stool. Such bleeding causes loss of iron from the body. Long-term blood loss due to regular use of aspirin can lead to Reference iron-deficiency anemia. Lost iron can be replaced with iron supplements. Iron supplementation should be used only in cases of iron deficiency verified with laboratory tests.

Stomach acid may facilitate iron absorption. H-2 blocker drugs reduce stomach acid and are associated with decreased dietary iron absorption.⁷³ People with ulcers may also be iron deficient due to blood loss and benefit from iron supplementation. Iron levels in the blood can be checked with lab tests.

Some studies suggest the taking of too much iron by individuals who are not iron deficient can result in tissue damage that may contribute to heart disease.⁷⁴ Test tube studies have shown dipyridamole blocks platelet clumping caused by iron,⁷⁵ which might reduce the damage caused by this mineral. Controlled human studies are needed to test this possibility.

NSAIDs cause gastrointestinal (GI) irritation, bleeding, and iron loss.⁷⁷ Iron supplements can cause GI irritation.⁷⁸ However, iron supplementation is sometimes needed in people taking NSAIDs if those drugs have caused enough blood loss to lead to Reference iron deficiency. If both iron and etodolac are prescribed, they should be taken with food to reduce GI irritation and bleeding risk.

Stomach acid may increase absorption of iron from food. H-2 blocker drugs reduce stomach acid and are associated with decreased dietary iron absorption.⁷⁹ The iron found in supplements is available to the body without the need for stomach acid. People with ulcers may be Reference iron deficient due to blood loss. If iron deficiency is present, iron supplementation may be beneficial. Iron levels in the blood can be checked with lab tests.

Haloperidol may cause decreased blood levels of iron.⁸¹ The importance of this interaction remains unclear. Iron should not be supplemented unless a deficiency is diagnosed.

Absorption of ferrous citrate, an iron compound that is usually well absorbed, is reduced in individuals taking hyoscyamine;⁸² therefore, these two substances should not be taken at the same time.

NSAIDs cause gastrointestinal (GI) irritation, bleeding, and iron loss.⁸³ Iron supplements can cause GI irritation.⁸⁴ However, iron supplementation is sometimes needed in people taking NSAIDs if those drugs have caused enough blood loss to lead to Reference iron deficiency. If both iron and ibuprofen are prescribed, they should be taken with food to reduce GI irritation and bleeding risk.

Antacids, including magnesium hydroxide, may reduce the absorption of dietary iron. Iron supplements do not require stomach acid for absorption and one human study found that a magnesium hydroxide/Reference aluminum hydroxide antacid did not decrease supplemental iron absorption.⁸⁶

NSAIDs cause gastrointestinal (GI) irritation, bleeding, and iron loss.⁸⁸ Iron supplements can cause GI irritation.⁸⁹ However, iron supplementation is sometimes needed in people taking NSAIDs if those drugs have caused enough blood loss to lead to Reference iron deficiency. If both iron and nabumetone are prescribed, they should be taken with food to reduce GI irritation and bleeding risk.

NSAIDs cause gastrointestinal (GI) irritation, bleeding, and iron loss.⁹⁰ Iron supplements can cause GI irritation.⁹¹ However, iron supplementation is sometimes needed in people taking NSAIDs if those drugs have caused enough blood loss to lead to Reference iron deficiency. If both iron and naproxen are prescribed, they should be taken with food to reduce GI irritation and bleeding risk.

Neomycin can decrease absorption or increase elimination of many nutrients, including Reference calcium, carbohydrates, Reference beta-carotene, fats, Reference folic acid, Reference iron, Reference magnesium, Reference potassium, sodium, and Reference vitamin A, Reference vitamin B12, Reference vitamin D, and Reference vitamin K.^{92 , 93} Surgery preparation with oral neomycin is unlikely to lead to deficiencies. It makes sense for people taking neomycin for more than a few days to also take a Reference multivitamin-mineral supplement.

Stomach acid may increase absorption of iron from food. H-2 blocker drugs reduce stomach acid and are associated with decreased dietary iron absorption.⁹⁴ The iron found in supplements is available to the body without the need for stomach acid. People with ulcers may be iron deficient due to blood loss. If Reference iron deficiency is present, iron supplementation may be beneficial. Iron levels in the blood can be checked with lab tests.

NSAIDs cause gastrointestinal (GI) irritation, bleeding, and iron loss.⁹⁵ Iron supplements can cause GI irritation.⁹⁶ However, iron supplementation is sometimes needed in people taking NSAIDs if those drugs have caused enough blood loss to lead to Reference iron deficiency. If both iron and oxaprozin are prescribed, they should be taken with food to reduce GI irritation and bleeding risk.

Stomach acid may facilitate iron absorption. H-2 blocker drugs reduce stomach acid and are associated with decreased dietary iron absorption.¹⁰⁰ People with ulcers may also be iron deficient due to blood loss and benefit from iron supplementation. Iron levels in the blood can be checked with lab tests.

In a study of nine healthy people, sodium bicarbonate administered with 10 mg of iron led to lower iron levels compared to iron administered alone.¹⁰¹ This interaction may be avoided by taking sodium bicarbonate-containing products two hours before or after iron-containing supplements.

Stanozolol was associated with iron depletion in a group of 16 people.¹⁰² The results suggest that people taking this drug on a regular basis have their iron status monitored by the prescribing doctor. There is insufficient information to recommend routine iron supplementation during stanozolol treatment.

In a double-blind study of patients who had developed a cough attributed to an ACE inhibitor, supplementation with iron (in the form of 256 mg of ferrous sulfate per day) for four weeks reduced the severity of the cough by a statistically significant 45%, compared with a nonsignificant 8% improvement in the placebo group.⁷¹

In a double-blind study of patients who had developed a cough attributed to an ACE inhibitor, supplementation with iron (in the form of 256 mg of ferrous sulfate per day) for four weeks reduced the severity of the cough by a statistically significant 45%, compared with a nonsignificant 8% improvement in the placebo group.⁷²

In a double-blind study of patients who had developed a cough attributed to an ACE inhibitor, supplementation with iron (in the form of 256 mg of ferrous sulfate per day) for four weeks reduced the severity of the cough by a statistically significant 45%, compared with a nonsignificant 8% improvement in the placebo group.⁷⁶

In a double-blind study of patients who had developed a cough attributed to an ACE inhibitor, supplementation with iron (in the form of 256 mg of ferrous sulfate per day) for four weeks reduced the severity of the cough by a statistically significant 45%, compared with a nonsignificant 8% improvement in the placebo group.⁸⁰

In a double-blind study of patients who had developed a cough attributed to an ACE inhibitor, supplementation with iron (in the form of 256 mg of ferrous sulfate per day) for four weeks reduced the severity of the cough by a statistically significant 45%, compared with a nonsignificant 8% improvement in the placebo group.⁸⁵

In a double-blind study of patients who had developed a cough attributed to an ACE inhibitor, supplementation with iron (in the form of 256 mg of ferrous sulfate per day) for four weeks reduced the severity of the cough by a statistically significant 45%, compared with a nonsignificant 8% improvement in the placebo group.⁸⁷

In a double-blind study of patients who had developed a cough attributed to an ACE inhibitor, supplementation with iron (in the form of 256 mg of ferrous sulfate per day) for four weeks reduced the severity of the cough by a statistically significant 45%, compared with a nonsignificant 8% improvement in the placebo group.⁹⁷

In a double-blind study of patients who had developed a cough attributed to an ACE inhibitor, supplementation with iron (in the form of 256 mg of ferrous sulfate per day) for four weeks reduced the severity of the cough by a statistically significant 45%, compared with a nonsignificant 8% improvement in the placebo group.⁹⁸

In a double-blind study of patients who had developed a cough attributed to an ACE inhibitor, supplementation with iron (in the form of 256 mg of ferrous sulfate per day) for four weeks reduced the severity of the cough by a statistically significant 45%, compared with a nonsignificant 8% improvement in the placebo group.⁹⁹

In a double-blind study of patients who had developed a cough attributed to an ACE inhibitor, supplementation with iron (in the form of 256 mg of ferrous sulfate per day) for four weeks reduced the severity of the cough by a statistically significant 45%, compared with a nonsignificant 8% improvement in the placebo group.¹⁰³

Iron supplements taken with carbidopa may interfere with the action of the drug.¹⁰⁴

Iron supplements taken with carbidopa interfere with the action of the drug.¹⁰⁵ People taking carbidopa should not supplement iron without consulting the prescribing physician.

Minerals such as aluminum, Reference calcium, Reference copper, Reference iron, Reference magnesium, Reference manganese, and Reference zinc can bind to ciprofloxacin, greatly reducing the absorption of the drug.^{106 , 107 , 108 , 109} Because of the mineral content, people are advised to take ciprofloxacin two hours after consuming dairy products (milk, cheese, yogurt, ice cream, and others), antacids (Maalox®, Mylanta®, Tums®, Rolaids®, and others), and mineral-containing supplements.¹¹⁰

Taking mineral supplements or antacids that contain aluminum, Reference calcium, Reference iron, Reference magnesium, or Reference zinc at the same time as tetracyclines inhibits the absorption of the drug.¹¹¹ Therefore, individuals should take tetracyclines at least two hours before or after products containing minerals.

Many minerals can decrease the absorption and reduce effectiveness of doxycycline, including Reference calcium, Reference magnesium, Reference iron, Reference zinc, and others.¹¹² To avoid these interactions, doxycycline should be taken two hours before or two hours after dairy products (high in calcium) and mineral-containing antacids or supplements.

A review of interactions involving quinolone antibiotics indicated that supplements containing iron, when taken at the same time as gemifloxacin, might reduce absorption of the drug up to 50%.¹¹³ Consequently, gemifloxacin and supplements containing iron should not be taken at the same time.

Taking iron supplements concomitantly with levofloxacin can reduce the absorption—and thus the effectiveness—of the drug.¹¹⁴ Therefore, nutritional supplements containing iron, if used, should be taken two hours before or after taking levofloxacin.

Iron supplements have been found to decrease methyldopa absorption.^{115 , 116} Taking methyldopa two hours before or after iron-containing products can help avoid this interaction.

Minerals including Reference calcium, Reference iron, Reference magnesium, and Reference zinc can bind to fluoroquinolones, including ofloxacin, greatly reducing drug absorption.¹¹⁷ Ofloxacin should be taken four hours before or two hours after consuming antacids (Maalox®, Mylanta®, Tumms®, Rolaids® and others) that may contain these minerals and Reference mineral-containing supplements.¹¹⁸

Penicillamine binds iron. When taken with iron, penicillamine absorption and activity are reduced.¹¹⁹ Four cases of penicillamine-induced kidney damage were reported when concomitant iron therapy was stopped, which presumably led to the increased penicillamine absorption and toxicity.¹²⁰

Taking risedronate at the same time as Reference iron, Reference zinc, or Reference magnesium may reduce the amount of drug absorbed.¹²¹ Therefore, people taking risedronate who wish to supplement with these minerals should take them an hour before or two hours after the drug.

Iron can bind with sulfasalazine, decreasing sulfasalazine absorption and possibly decreasing iron absorption.¹²² This interaction can be minimized by taking iron-containing products two hours before or after sulfasalazine.

Many minerals can decrease the absorption of tetracycline, thus reducing its effectiveness. These minerals include aluminum (in antacids), Reference calcium (in antacids, dairy products, and supplements), Reference magnesium (in antacids and supplements), Reference iron (in food and supplements), Reference zinc (in food and supplements), and others.

Reference Iron , Reference magnesium, and Reference zinc may bind with warfarin, potentially decreasing their absorption and activity.¹²³ People on warfarin therapy should take warfarin and iron/magnesium/zinc-containing products at least two hours apart.

People treated with deferoxamine for dangerously high levels of iron should not take iron supplements, because iron exacerbates their condition, further increasing the need for the deferoxamine. They should read all labels carefully for iron content. All people treated with deferoxamine should consult their prescribing doctor before using any iron-containing products.

Iron may interfere with captopril absorption. They should not be taken within two hours of each other.¹²⁴

In a double-blind study of patients who had developed a cough attributed to an ACE inhibitor, supplementation with iron (in the form of 256 mg of ferrous sulfate per day) for four weeks reduced the severity of the cough by a statistically significant 45%, compared with a nonsignificant 8% improvement in the placebo group.¹²⁵

Menstrual blood loss is typically reduced with use of OCs. This can lead to increased iron stores and, presumably, a decreased need for iron in premenopausal women.¹²⁶ Premenopausal women taking OCs should have their iron levels monitored and talk with their prescribing doctor before using iron-containing supplements.

Iron deficiency has been reported to impair the body’s ability to make its own thyroid hormones,¹²⁷ which could increase the need for thyroid medication. In a preliminary trial, iron supplementation given to iron-deficient women with low blood levels of thyroid hormones, partially normalized these levels.¹²⁸ Diagnosing iron deficiency requires the help of a doctor. The body’s ability to make its own thyroid hormones is also reduced during low-calorie dieting. Iron supplementation (27 mg per day) was reported in a controlled study to help maintain normal thyroid hormone levels in obese patients despite a very low-calorie diet.¹²⁹

However, iron supplements may decrease absorption of thyroid hormone medications.^{130 , 131} People taking thyroid hormone medications should talk with their doctor before taking iron-containing products. If advised to supplement, iron and the drug should not be taken within less than four hours of each other.

Menstrual blood loss is typically reduced with use of OCs. This can lead to increased iron stores and, presumably, a decreased need for iron in premenopausal women.¹³² Premenopausal women taking OCs should have their iron levels monitored and talk with their prescribing doctor before using iron-containing supplements.

Menstrual blood loss is typically reduced with use of OCs. This can lead to increased iron stores and, presumably, a decreased need for iron in premenopausal women.¹³³ Premenopausal women taking OCs should have their iron levels monitored and talk with their prescribing doctor before using iron-containing supplements.

Menstrual blood loss is typically reduced with use of OCs. This can lead to increased iron stores and, presumably, a decreased need for iron in premenopausal women.¹³⁴ Premenopausal women taking OCs should have their iron levels monitored and talk with their prescribing doctor before using iron-containing supplements.

Menstrual blood loss is typically reduced with use of OCs. This can lead to increased iron stores and, presumably, a decreased need for iron in premenopausal women.¹³⁵ Premenopausal women taking OCs should have their iron levels monitored and talk with their prescribing doctor before using iron-containing supplements.

Iron supplements can cause stomach irritation. Use of iron supplements with indomethacin increases the risk of stomach irritation and bleeding.¹³⁶ However, stomach bleeding causes iron loss. If both iron and indomethacin are prescribed, they should be taken with food to reduce stomach irritation and bleeding risk.

Menstrual blood loss is typically reduced with use of OCs. This can lead to increased iron stores and, presumably, a decreased need for iron in premenopausal women.¹³⁷ Premenopausal women taking OCs should have their iron levels monitored and talk with their prescribing doctor before using iron-containing supplements.

Menstrual blood loss is typically reduced with use of OCs. This can lead to increased iron stores and, presumably, a decreased need for iron in premenopausal women.¹³⁸ Premenopausal women taking OCs should have their iron levels monitored and talk with their prescribing doctor before using iron-containing supplements.

Iron deficiency has been reported to impair the body’s ability to make its own thyroid hormones,¹³⁹ which could increase the need for thyroid medication. In a preliminary trial, iron supplementation given to iron-deficient women with low blood levels of thyroid hormones, partially normalized these levels.¹⁴⁰ Diagnosing iron deficiency requires the help of a doctor. The body’s ability to make its own thyroid hormones is also reduced during low-calorie dieting. Iron supplementation (27 mg per day) was reported in a controlled study to help maintain normal thyroid hormone levels in obese patients despite a very low-calorie diet.¹⁴¹

However, iron supplements may decrease absorption of thyroid hormone medications.^{142 , 143} People taking thyroid hormone medications should talk with their doctor before taking iron-containing products.  If advised to supplement, iron and the drug should not be taken within less than four hours of each other.

Iron deficiency has been reported to impair the body’s ability to make its own thyroid hormones,¹⁴⁴ which could increase the need for thyroid medication. In a preliminary trial, iron supplementation given to iron-deficient women with low blood levels of thyroid hormones, partially normalized these levels.¹⁴⁵ Diagnosing iron deficiency requires the help of a doctor. The body’s ability to make its own thyroid hormones is also reduced during low-calorie dieting. Iron supplementation (27 mg per day) was reported in a controlled study to help maintain normal thyroid hormone levels in obese patients despite a very low-calorie diet.¹⁴⁶

However, iron supplements may decrease absorption of thyroid hormone medications.^{147 , 148} People taking thyroid hormone medications should talk with their doctor before taking iron-containing products. If advised to supplement, iron and the drug should not be taken within less than four hours of each other.

Iron deficiency has been reported to impair the body’s ability to make its own thyroid hormones,¹⁴⁹ which could increase the need for thyroid medication. In a preliminary trial, iron supplementation given to iron-deficient women with low blood levels of thyroid hormones, partially normalized these levels.¹⁵⁰ Diagnosing iron deficiency requires the help of a doctor. The body’s ability to make its own thyroid hormones is also reduced during low-calorie dieting. Iron supplementation (27 mg per day) was reported in a controlled study to help maintain normal thyroid hormone levels in obese patients despite a very low-calorie diet.¹⁵¹

However, iron supplements may decrease absorption of thyroid hormone medications.^{152 , 153} People taking thyroid hormone medications should talk with their doctor before taking iron-containing products. If advised to supplement, iron and the drug should not be taken within less than four hours of each other.

Menstrual blood loss is typically reduced with use of OCs. This can lead to increased iron stores and, presumably, a decreased need for iron in premenopausal women.¹⁵⁴ Premenopausal women taking OCs should have their iron levels monitored and talk with their prescribing doctor before using iron-containing supplements.

Taking calcium, iron, magnesium, or zinc at the same time as minocycline can decrease the absorption of both the drug^{155 , 156} and the mineral. Therefore, calcium, iron, magnesium, or zinc supplements, if used, should be taken an hour before or after the drug.

Menstrual blood loss is typically reduced with use of OCs. This can lead to increased iron stores and, presumably, a decreased need for iron in premenopausal women.¹⁵⁷ Premenopausal women taking OCs should have their iron levels monitored and talk with their prescribing doctor before using iron-containing supplements.