Easy-to-read medicine information about iron supplements – what they are, how to take them safely and possible side effects.
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What are iron supplements?
Iron supplements are used to treat or prevent low levels of iron in your blood (iron deficiency). They increase the amount of iron stores in your body. Most people get enough iron from a healthy, balanced diet. However, some people may need iron supplementation, such as:
- pregnant women or teenage girls, who have higher iron requirements
- those who do not absorb iron normally, such as people with renal failure or gut problems that cause malabsorption
- anyone with ongoing or excessive blood loss, such as in women with heavy periods (menorrhagia).
If you have low iron levels, your doctor may prescribe, or your pharmacist may recommend, iron supplements to be taken by mouth (called oral iron supplements). In certain circumstances if oral iron supplements are not effective (that is, if they cannot be absorbed from your gut) or if they cannot be tolerated, iron supplements can be given by injection. Read more about iron injection.
Note: Iron supplements should not be used by people with haemochromatosis, a rare condition that occurs when too much iron builds up in the body. The excess iron can cause damage to their organs.
Types of iron supplements
- Iron supplements are available on prescription, or you can buy them without a prescription from pharmacies, health stores or on the internet.
- There are a different forms of iron available in New Zealand, such as ferrous sulfate and ferrous fumarate (ferrous is the Latin word to describe iron).
- Each of these has a different amount of actual iron (called elemental iron).
- The usual dose of oral elemental iron to treat iron-deficiency is 100 to 200 mg daily. Lower doses may be used to prevent iron-deficiency.
- There is no particular advantage of one type over another, as long as you receive enough elemental iron, so the choice of medicine is dependent on the risk of side effects and cost.
|Examples of iron products in New Zealand||Description|
|Ferro-gradumet® or Ferrograd®||
Some dietary supplements (such as Floradix) and multivitamins have small quantities of iron in them. The amount of iron in these products is not enough to treat iron deficiency. If you are unsure about the best supplement for you, talk to your doctor or pharmacist.
- The dose needed will vary depending on whether the iron supplement is used to treat or prevent low iron levels.
- It is usually prescribed between 1 to 3 doses a day.
- Always take your iron supplement exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it and any special instructions. Talk to your doctor or pharmacist if you have any questions regarding your medication or dosage.
How to take iron supplements
- Take on an empty stomach: Iron supplements are best taken on an empty stomach (usually 1 hour before or 2 hours after meals). But, if you get an upset stomach or you feel sick (queasy), you can take this medication with food.
- Iron interacts with foods and beverages: Avoid having dairy products (milk), tea, coffee or antacids within 2 hours before or after this medication because they decrease its effectiveness.
- Taking your dose with vitamin C: Taking vitamin C (such as orange juice or apple juice) with iron may increase its absorption, but there is very limited evidence to support this.
- Tablets or capsules can irritate your gut: Take your iron tablets or capsules with a full glass of water. Do not lie down for at least 10 minutes after taking your dose.
- Swallow extended-release tablets whole: Do not crush or chew extended-release tablets, as this will release all of the medication at once, increasing the risk of side effects.
- Measure you dose carefully: If you are taking the liquid form for adults, carefully measure the dose using a special measuring device or spoon. Do not use a household spoon because you may not get the correct dose.
- Liquid forms can stain the teeth: Liquid iron can cause temporary discolouration of the teeth. To prevent staining, place the liquid on the back of your tongue with a dropper, use a straw or brush your teeth after each dose.
- It is not harmful if you miss a dose of your iron supplement. If you miss a dose, just take your next dose at the right time. Do not take double the dose.
- Storage: remember to keep iron supplements out of the reach and sight of children, because an overdose may be fatal. (Iron is not harmful when given to children in the amounts recommended by your doctor. You must not give your child more than this).
How long should I take iron supplements for?
The length of treatment will depend on how low your iron levels are. To diagnose iron deficiency your doctor will recommend you have a blood test, and if you are found to be iron deficient, you will be prescribed iron supplements. A few weeks after taking iron supplements, you will have another blood test to check if the supplements are working. When your blood level is back to normal, you should continue to take iron for at least 3 further months. This will build up the stores of iron in your body.
Possible side effects
Like all medicines, iron supplements can cause side effects, although not everyone gets them. Often effects improve as your body gets used to the new medicine.
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- Some multivitamin and mineral products may contain iron, so check with your doctor or pharmacist if you are taking these.
- Some medicines available without a prescription may react with iron supplements, such as antacids (eg, Mylanta) or supplements containing aluminium (eg, Alu-Tab®), calcium (eg, Osteo®), magnesium (eg, Chelated Magnesium®) or zinc (eg, Zincaps®). Do not take these within 2 hours of taking iron supplements. Check with your pharmacist about any interactions.
The following links have more information on iron supplements.
- Oral iron New Zealand Formulary