What Are the Side Effects of Taking Iron Tablets?

• Constipation and dark stools: Use a stool softener, increase your intake of water, fluids and fiber and include probiotics in your diet.
• Stomach upset: Stomach upset can be controlled by taking your iron supplement in smaller amounts with meals or snacks, but not on an empty stomach. If this doesn’t work, switching to another form of iron is recommended.
• Stained teeth: Mixing the iron tablet with water or juice and drinking with a straw helps avoid staining. Iron stains can also be removed by brushing teeth with baking soda or peroxide.
• Metallic taste: Drinking water or chewing gum may help eliminate a metallic aftertaste.
• Heartburn: Taking an iron supplement with food and avoiding it at bedtime can help reduce heartburn.

An iron deficiency may be caused by:

• Diet low in iron
• Conditions that cause poor absorption of iron, such as Celiac disease, Crohn’s disease, cystic fibrosis and chronic pancreatitis
• Blood loss due to heavy menstrual periods, ulcers, some cancers or gastrointestinal bleeding
• Pregnancy, which increases the demand for new red blood cells to support the fetus.
• Blood thinners, such as aspirin or heparin
• Kidney failure and hemodialysis

There are several benefits to taking iron supplements. They may: 

• Help maintain normal blood iron levels
• Prevent symptoms of iron deficiency
• Treat iron deficiency anemia
• Improve surgical outcomes and reduce the risk of complications
• Help with attention deficit hyperactivity disorder (ADHD)
• Improve stamina

Before starting to take iron supplements, talk to your doctor if you:

• Have any known drug allergies
• Have difficulty swallowing
• Take other medications. Iron pills may interfere with: 
  • Medications used for seizures, hypothyroidism, Parkinson's disease
  • Tetracycline, penicillin and ciprofloxacin

Other precautions to take include the following:

• Keep iron pills away from children to avoid the risk of iron overdose and iron toxicity. 
• If you forget to take a dose, just skip it and then resume your regular dosing routine. Do not double dose.

Here are some tips to ensure better absorption of iron supplements:

• Take them on an empty stomach. If this causes stomach upset, switch to taking them with a small amount of food to avoid this problem.
• Take them with vitamin C supplements or orange juice.
• Don’t take them with milk, calcium-rich foods or calcium supplements, coffee or black tea. It’s best to consume these 2 hours before or after taking iron supplements.
• Don’t take them with certain medications like antacids, tetracycline and fluoroquinolones. Wait 2 hours before taking either one.

Iron supplements can also administered in the following ways:

• Oral: Iron supplements can be taken orally in the form of pills and syrups. Ferrous salts used in oral iron supplements include ferrous sulfate, ferrous fumarate, ferrous gluconate and ferrous succinate. It may take up to 2 months for iron levels to become normal while taking oral iron supplements.
• Parenteral: Parenteral iron supplements include iron dextran, iron sucrose, iron carboxymaltose and iron isomaltoside 1000. Iron supplement injections are given intravenously or intramuscularly when:
  • Oral iron supplements are not tolerated.
  • Absorption is compromised by illnesses.
  • You cannot swallow.
  • You have an underlying inflammatory condition, such as inflammatory bowel disease or kidney disease.
  • The level of hemoglobin needs to be increased quickly before elective surgery, post-operatively, post-transfusion or post-partum.

For most people, hemoglobin and iron levels usually return to normal after 2 months of iron therapy. In some cases, however, iron supplements may have to be continued for another 6-12 months. 

Your doctor will determine how long you need to take iron supplements based on regular blood tests that measure your body’s iron levels.