If you are currently being treated with any of the medications discussed below, you should not use iron without first talking to your health care provider.

Iron may interfere with the absorption of many different medications. For this reason, it is best to take iron supplements at least 2 hours before or 2 hours after taking medications. This is particularly true for the medications listed below.

The following medications may reduce the absorption of iron:

Cholestyramine and Colestipol -- These are two cholesterol-lowering medications known as bile acid sequestrants.

Medications used to treat ulcers or other stomach problems -- Examples of anti-ulcer medications include cimetidine (Tagamet), ranitidine (Zantac), famotidine (Pepcid), and nizatidine (Axid). These medications belong to a class of drugs known as H2 receptor blockers. They change the pH in the stomach and subsequently alter the absorption of iron. It is possible that this effect could occur with other antiulcer medications including antacids and proton pump inhibitors, including omeprazole (Prilosec).

Iron decreases the absorption of the following medications:

Tetracyclines -- These are a class of antibiotics that include doxycycline (Vibramycin), minocycline (Minocin), and tetracycline (Sumycin).

Quinolones -- These are a class of antibiotics that include ciprofloxacin (Cipro), norfloxacin (Noroxin), and levofloxacin (Levaquin).

ACE inhibitors -- These are a class of medications used to treat high blood pressure. Examples include captopril (Capoten), enalapril (Vasotec), and lisinopril (Zestril or Prinivil).

Iron may reduce the effectiveness or blood levels of the following medications:

Carbidopa and Levodopa -- Iron lowers blood levels of carbidopa and levedopa (Sinemet ) but it is unclear whether these changes lower the effectiveness of the drugs.

Levothyroxine -- Iron may decrease the effectiveness of this thyroid replacement hormone. A health care provider will monitor thyroid function closely in those taking iron supplements with thyroid medications, including Armour Thyroid and levothyroxine (Synthroid).

Iron levels may be increased by:

Birth control medications -- Birth control medicines, or oral contraceptives, may increase iron levels, thereby decreasing the need for extra iron. Be careful if you are taking oral contraceptives not to take multiple vitamins that contain iron.