Tardyferon (Ferrous Sulfate) in Spain: Iron Tablets
Medically Reviewed by Dr. Pedro Yelamo Vera, MD
Licensed Physician No. 484814280 · Official Medical College of Bizkaia (Spain)Last reviewed: 29 October 2026
Tardyferon is slow-release ferrous sulfate, a prescription iron tablet in Spain. What it treats, what to avoid with it and why black stools happen.
You don't have to figure this out alone
Dr. Pedro Yelamo Vera is an independent, bilingual GP licensed in Spain. Book a 15-minute video consultation in English or Spanish for €50, with a private electronic prescription issued under Spanish law when clinically appropriate.
Tardyferon is a Spanish brand of ferrous sulfate, an iron tablet that releases its iron slowly. Doctors use it to treat and prevent iron-deficiency anaemia, when the body lacks iron to make red blood cells. In Spain it needs a prescription. It is for adults and for children who weigh at least 28 kg.
- Tardyferon is slow-release ferrous sulfate. It tops up iron in iron-deficiency anaemia.
- It needs a prescription in Spain.
- Low iron always has a cause. A doctor should look for it, not just give tablets.
- Dark or black stools are normal with iron. Black, tarry stools with dizziness or pain are not.
- Keep iron tablets away from children. Too much iron can poison a child.
Dr. Pedro Yelamo Vera is a GP licensed in Spain (Colegiado No. 484814280).
For a medical emergency, call 112 or go to the nearest local emergency department. Do not wait for a video consultation or an online reply.
What is Tardyferon used for?
Tardyferon is used when blood tests show you are low in iron. The leaflet lists two uses: to treat iron-deficiency anaemia and to prevent it in people who lack iron. Iron is what red blood cells use to carry oxygen. When it runs low, you may feel tired, short of breath or dizzy, and look pale.
The tablets are orange-pink and come in packs of 30. They release iron slowly as they pass through the gut. Swallow them whole with a glass of water. Do not suck, chew or keep them in your mouth. That can cause mouth ulcers and stain the teeth.
The doctor or the leaflet tells you how many to take and for how long. The plan is usually checked with new blood tests, so keep taking them until the doctor says to stop, even if you feel better.
Why does the cause of low iron matter?
Iron tablets fix the shortage, but not the reason for it. The leaflet says the cause should be looked for and treated. Common causes are:
- Heavy periods. This is one of the most frequent reasons in women.
- Pregnancy, when the body needs more iron.
- Bleeding from the stomach or gut, for example from an ulcer, piles or anti-inflammatory painkillers.
- A diet low in iron, or a gut that does not absorb it well, as in coeliac disease.
In men and in women after menopause, low iron needs a careful look for bleeding in the gut. Iron also works less well when the anaemia comes from long-term inflammation. Our anaemia and vitamin deficiency page explains what a doctor checks.
Is there a UK or US version of Tardyferon?
The ingredient, ferrous sulfate, is common everywhere. The Tardyferon brand is what you will meet in Spain. These are the names you may know from home. They contain the same kind of iron, but the amount and release type can differ, so they are not swapped one for one.
| Name | What it is | Where |
|---|---|---|
| Tardyferon | Slow-release ferrous sulfate | Spain (prescription) |
| Ferrous sulfate tablets | Standard ferrous sulfate | UK (prescription or pharmacy) |
| Iron supplements | Ferrous sulfate, fumarate or gluconate | US |
| Ferrous fumarate or gluconate | Other iron salts with a different iron content | UK, US |
If you took iron at home, bring the name of the product and your last blood results to the visit.
Do you need a prescription for Tardyferon in Spain?
Yes. Tardyferon is listed as a prescription medicine (medicamento sujeto a prescripción médica) on the AEMPS CIMA database. It is the only ferrous sulfate medicine CIMA shows on sale in Spain. In the UK, ferrous sulfate is sold on prescription and in pharmacies, so the rule in Spain may surprise you.
Our guide on which medicines need a prescription in Spain covers other common examples.
Low iron on a blood test, or tired all the time?
You can book a video visit with a GP licensed in Spain, in English or Spanish. He goes through your results and explains what they mean and what to do next.
What should you not take with Tardyferon?
Many things stop iron from being absorbed. The leaflet says to keep these at least 2 hours apart from Tardyferon:
- Antacids and stomach powders with aluminium, calcium or magnesium.
- Some antibiotics: tetracyclines such as doxycycline, quinolones such as ciprofloxacin, and cefdinir.
- Levothyroxine, the thyroid hormone.
- Calcium or zinc supplements.
- Bisphosphonates for weak bones.
- Levodopa, carbidopa, entacapone and methyldopa.
- Penicillamine and trientine.
Food and drink matter too. Large amounts of tea, coffee or red wine lower absorption. So do milk, cheese, eggs and bran. Leave at least 2 hours between them and your tablet. Vitamin C, as in orange juice, can help the body take up iron. Do not take iron injections at the same time. Tell your pharmacist about every medicine you use.
Who should not take Tardyferon?
- People who already have too much iron in the body.
- People whose anaemia is not caused by low iron, such as thalassaemia. Extra iron can harm them.
- Children who weigh less than 28 kg. That is roughly under 9 to 10 years old.
- People who find it hard to swallow. A tablet that goes down the wrong way can damage the airway. Tell your doctor first.
In pregnancy, the leaflet says it can be used when it is clinically needed. Ask your doctor first. It can be used while breastfeeding. Our pregnancy care page explains how a GP can help.
What Tardyferon does not treat
- Tiredness from other causes, such as thyroid problems, poor sleep or low mood.
- Anaemia from low vitamin B12 or folate. That needs a different treatment.
- The bleeding itself. Iron refills the stores, but a heavy period or a gut ulcer needs its own care.
Is black stool normal on iron tablets?
Yes. Dark or black stools are a common, harmless effect of iron. Other common effects are constipation, diarrhoea, a swollen belly, stomach pain and feeling sick. Taking the tablet with food can help if your stomach is upset. See a doctor if:
- Stomach pain or sickness does not settle.
- You get a cough that will not go away, or you cough up blood, after a tablet went down the wrong way.
- You feel no better after some weeks, or your blood tests do not improve.
- You get a rash, itching or swelling.
Call 112 if your stools are black, sticky and tarry and you also feel dizzy, faint or have stomach pain. Also call 112 if you vomit blood. These can be signs of bleeding in the gut, which is different from the normal colour change.
What if a child swallows iron tablets?
Too much iron is dangerous for young children. MedlinePlus warns that it is a leading cause of fatal poisoning in children under 6. Keep the pack locked away and out of sight. If a child swallows any, call the Spanish poison line (Servicio de Información Toxicológica, 91 562 04 20) straight away, even if the child seems well. Call 112 if the child vomits, is drowsy, has trouble breathing or will not wake up.
Talking it through with a doctor by video
Dr. Yelamo is a GP licensed in Spain. He sees adults, children and pregnant patients by video, every day from 07:30 to 20:30 (Spain time). In the visit he will:
- Go through your blood results, such as haemoglobin and ferritin.
- Ask about periods, diet, bowel habits and any bleeding, to look for the cause.
- Decide whether iron tablets are right, and which tests you need next.
- Check how iron fits with your other medicines.
He does not promise any test or prescription before the visit. Where clinically appropriate, following a genuine evaluation. Treatment and prescriptions are issued solely at the doctor's discretion based on evidence-based clinical guidelines.
A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.
See how the Urgent Care video visit works. It lasts 15 minutes and costs €50.
This guide is general information. It does not replace the package leaflet or the advice of your doctor or pharmacist.
Frequently asked questions
What is Tardyferon?
A Spanish brand of slow-release ferrous sulfate. Doctors use it to treat and prevent iron-deficiency anaemia.
Do I need a prescription for Tardyferon in Spain?
Yes. CIMA lists Tardyferon as a prescription medicine. A doctor should check your blood results and the cause of low iron first.
Is Tardyferon the same as ferrous sulfate in the UK?
It is the same iron salt, ferrous sulfate, but in a slow-release tablet. The iron content can differ, so a doctor or pharmacist should compare them.
Why are my stools black on iron?
Dark or black stools are a common, harmless effect of iron. Black, tarry stools with dizziness, fainting or stomach pain need urgent help: call 112.
Can I take Tardyferon with tea or milk?
Tea, coffee, milk, cheese and eggs lower iron absorption. The leaflet says to leave at least 2 hours between them and the tablet.
Is Tardyferon safe in pregnancy?
The leaflet says it can be used in pregnancy when clinically needed. Ask your doctor before you start.
Sources
- AEMPS CIMA: Tardyferon package leaflet
- MedlinePlus: Iron supplements
- NHS: Ferrous sulfate
- NHS: Iron deficiency anaemia
Related guides
Medical Citations & Sources
This content is written and reviewed by a licensed physician with reference to the following official health authorities.
