Iron overdose: why iron tablets are dangerous in children and what to do

Iron is a mineral the body needs to make healthy red blood cells, which carry oxygen. The NHS says ferrous sulfate is a type of iron used as a medicine to treat and prevent iron deficiency anaemia, and that it comes as tablets or drops. It is available on prescription and to buy from pharmacies. Ferrous fumarate is another iron medicine. Because the tablets are widely available and often kept at home, they are a recognised cause of accidental poisoning in young children.

An iron overdose means taking more than the recommended amount, either by accident, as a child swallowing tablets, or deliberately, or through a dosing error in an adult. The NHS poisoning page describes poisoning as what can happen if you swallow, touch or breathe in substances that are harmful, such as chemicals or medicines.

The NHS pages read for this guide do not give the amount of iron that is dangerous, and it would be unsafe to guess. The right approach is to treat any amount over the recommended dose as a reason to call for advice, particularly for a child.

For ferrous sulfate the NHS says taking more than the recommended dose can cause vomiting, stomach pain or diarrhoea, and that in serious cases a person may vomit blood, have a seizure or fit, or become unconscious. The NHS also says that in children a small amount more than their recommended dose of ferrous fumarate can be dangerous, and that it is important to get medical advice if you or your child take too much because it can sometimes be dangerous.

The general poisoning page lists symptoms that may occur with poisons: feeling or being sick, diarrhoea, feeling sleepy, blurred vision, a high temperature or feeling hot, cold or shivery, confusion, difficulty breathing, seizures and loss of consciousness. It says symptoms may take a few hours or days to start. A person who looks well should therefore still be assessed if they may have swallowed too much.

Dark stools are a normal effect of iron. The NHS says darker than usual poo is common when taking iron and usually nothing to worry about, but it also says to talk to a doctor or call 111 straight away if your poo is black, tar-like or red, or has blood in or on it, or if you also feel unwell. A black stool in someone who has taken too much iron should be reported.

The NHS poisoning page says to call 999 or go to A&E if you think someone may have swallowed, touched or breathed in something harmful and they have lost consciousness, stopped breathing, have severe difficulty breathing, or have a seizure. It says to call NHS 111 if you are not sure whether something swallowed is harmful. For iron specifically, the NHS says to contact 111 for advice now if you or your child have taken more than the recommended dose.

• Do not try to make the person sick: the NHS says they could choke and stop breathing.

• Do not give the person anything to eat or drink, the NHS poisoning page advises.

• Put an unconscious person who is still breathing in the recovery position, and start CPR if they are unresponsive and not breathing.

• Try to find out what was taken and how much, and take the packaging, any remaining medicine and a sample of vomit in a container if possible.

• Do not drive to A&E yourself: the NHS says to ask someone to drive you or call 999 for an ambulance, and bring any medicines you take.

The NHS says people with poisoning need to be treated in hospital because it can make them seriously unwell and can be life threatening. Treatment depends on what has caused the poisoning and may include medicines (antidotes), a charcoal drink that can help stop some types of poisoning, treatments for symptoms such as fluids into a vein for dehydration, and removing what has caused the poisoning from the body.

The NHS adds that if you do not have symptoms you may not need any treatment but may still need to be monitored for several hours in case you become unwell. The pages read for this guide do not describe the specific antidote or tests used for iron, so the hospital team will explain those.

The NHS says to keep ferrous sulfate out of sight and reach of children, as an overdose may be fatal, and to keep ferrous fumarate out of children's reach because it can be very dangerous if they take it accidentally. The NHS poisoning page recommends storing medicines and chemicals out of reach of children, ideally in a locked cupboard, reading instructions to be sure of the correct dose, and keeping cleaning products in their original containers.

Keeping medicines in their original packaging, as the NHS poisoning page advises for chemicals, also helps make sure the leaflet and strength are available if something goes wrong. The NHS says that ferrous sulfate is not harmful if it has been prescribed for your child and you follow the doctor's instructions or the instructions on the packet.

If you take iron yourself, take it as directed. The NHS ferrous sulfate page says the usual adult dose for treating anaemia is usually one 200mg tablet once a day, but it may be 2 to 3 times a day, and that if you get side effects a doctor may advise taking it on alternate days. If you miss a dose, the NHS says not to take 2 doses to make up for it.

It helps to know what is expected. The NHS lists common side effects of ferrous sulfate as feeling or being sick, stomach discomfort or heartburn, losing your appetite, constipation, diarrhoea, darker than usual poo and, with drops, black stained teeth. It suggests taking it with or just after a meal if it upsets your stomach. These are not signs of poisoning on their own, but if they are severe, or if a larger-than-intended amount was taken, call for advice.

The NHS also advises that if you have an allergic reaction with swelling of lips, mouth, throat or tongue, fast breathing, or fainting, you should call 999, as it is a rare possibility with any medicine.

NHS 111 and 999 are the entry points for suspected overdose in the UK, and emergency treatment is provided by NHS hospitals. Pharmacists can give advice about safe storage and about the right dose to take, and they sell iron products as well as dispensing prescriptions. If someone has taken too much, do not wait to arrange an appointment with a private clinic: call 111 or 999 first.