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FURANTOIN 50 mg TABLETS

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About the medicine

How to use FURANTOIN 50 mg TABLETS

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This page provides general information and does not replace a doctor’s consultation. Always consult a doctor before taking any medication. Seek urgent medical care if symptoms are severe.

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Introduction

Package Leaflet: Information for the User

Furantoína 50 mg Tablets

Nitrofurantoin

Read all of this leaflet carefully before you start taking this medicine because it contains important information for you.

  • Keep this leaflet, you may need to read it again.
  • If you have any further questions, ask your doctor, pharmacist, or nurse.
  • This medicine has been prescribed for you only. Do not pass it on to others. It may harm them, even if their signs of illness are the same as yours.
  • If you get any side effects, talk to your doctor, pharmacist, or nurse. This includes any possible side effects not listed in this leaflet. See section 4.

Contents of the Package Leaflet

  1. What is Furantoína and what is it used for
  2. What you need to know before you take Furantoína
  3. How to take Furantoína
  4. Possible side effects
  5. Storage of Furantoína
  6. Contents of the pack and further information

1. What is Furantoína and what is it used for

The active ingredient of Furantoína is nitrofurantoin.

Nitrofurantoin is an antibiotic belonging to the group of nitrofurans.

Antibiotics are used to treat bacterial infections and are not effective against viral infections such as the flu or the common cold.

It is essential to follow the instructions regarding dosage, administration interval, and treatment duration indicated by your doctor.

Do not store or reuse this medication. If you have any leftover antibiotic after completing treatment, return it to the pharmacy for proper disposal. Do not throw away medicines via wastewater or household waste.

It is used to treat urinary tract infections caused by bacteria in girls over 6 years old, adolescents, and adult women.

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2. What you need to know before you take Furantoína

Do not take Furantoína:

  • If you are allergic to nitrofurantoin or any of the other components of this medication (listed in section 6).
  • For more than 7 consecutive days or in frequent repeat treatments, see the section on Warnings and Precautionsbelow.
  • If you have severe kidney problems.
  • If you have a blood disorder called porphyria.
  • If you have been diagnosed with a blood disorder called glucose-6-phosphate dehydrogenase deficiency, which is a substance that red blood cells need to function properly.
  • If you are pregnant and in the last two weeks of gestation.

Warnings and Precautions

The use of nitrofurantoin in prolonged treatments (either continuous or frequent repeat treatments) has been associated with the occurrence of severe pulmonary, hepatic, and hypersensitivity reactions.

Consult your doctor or pharmacist before starting to take Furantoína if you:

  • Have any kidney disease.
  • Have been diagnosed with any neurological disease.
  • Are prone to allergic reactions.
  • Have liver or lung problems.
  • Are diabetic.
  • Have anemia.
  • If you have a lack of vitamin B, especially a vitamin called folic acid.
  • Experience fatigue, yellowing of the skin or eyes, itching, skin rashes, joint pain, abdominal discomfort, nausea, vomiting, loss of appetite, dark urine, and pale or gray stools. These may be symptoms of a liver disorder.

Keep in mind that when taking Furantoína, your urine may turn a dark yellow or brown color. This is a normal effect and you should not stop taking the medication because of it.

Furantoína may interfere with urine glucose tests, potentially giving false positive results.

Children and Adolescents

The tablets are not recommended for girls under 6 years of age (see section 3). There is another formulation of this medication: Furantoína oral suspension, which is suitable for this population group.

Using Furantoína with Other Medicines

Tell your doctor or pharmacist if you are taking, have recently taken, or might take any other medicines, such as:

  • Antacids used to reduce stomach acidity, such as magnesium trisilicate. Take Furantoína at least 1 hour before or 2 hours after taking an antacid.
  • Medicines for the treatment of gout, such as probenecid and sulfinpyrazone, as the effect of Furantoína may be reduced.
  • Medicines for the treatment of ocular hypertension (glaucoma), such as carbonic anhydrase inhibitors, as they reduce the effect of Furantoína.
  • Medicines that reduce the acidity of the urine because they reduce the effect of Furantoína.
  • Other antibiotics, such as those belonging to the quinolone group, as it may reduce the effect of both antibiotics.

Using Furantoína with Food and Drinks

It is recommended to take Furantoína during meals or with a glass of milk and never on an empty stomach to increase tolerance and improve the absorption of the medication.

Pregnancy, Breastfeeding, and Fertility

If you are pregnant or breastfeeding, think you may be pregnant, or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine.

  • You must not take this medicine if you are in the last two weeks of pregnancy.
  • You should avoid taking Furantoína during breastfeeding if your baby is under three months old or if the child has a blood disorder called glucose-6-phosphate dehydrogenase deficiency (G6PD).

Driving and Using Machines

Taking this medicine may cause dizziness, so you should not take Furantoína if you need to drive or use machines.

3. How to Take Furantoína

Follow exactly the administration instructions of this medicine indicated by your doctor or pharmacist. If in doubt, consult your doctor or pharmacist again.

The recommended dose is: In women over 18 years old: 50-100 mg (1-2 tablets) every 8 hours for 5-7 days.

Provided you do not have significant renal impairment, the recommended dose is the same as for women over 18 years old.

Use in Children and Adolescents

In girls over 6 years old and adolescents, the recommended dose is 5-7 mg/kg body weight per day, not exceeding the adult dose, divided into four doses for 5-7 days.

If You Take More Furantoína Than You Should

If you (or someone else) swallow many tablets at once or if you think a child has swallowed some tablets, contact your doctor or pharmacist immediately. Overdose could cause stomach irritation, nausea, and vomiting.

In case of overdose or accidental ingestion, consult your doctor or pharmacist or call the Toxicological Information Service, phone 91 562 04 20, indicating the medicine and the amount taken. Bring this leaflet, any remaining tablets, and the packaging to the hospital or your doctor so they know which tablets you have taken.

If You Forget to Take Furantoína

If you forget to take a tablet, take it as soon as you remember, unless it is almost time for your next dose. Do not take a double dose to make up for forgotten doses.

If You Stop Taking Furantoína

Do not stop taking your medicine without talking to your doctor first, even if you feel better. It is very important that you continue taking Furantoína for the time indicated by your doctor, or the infection may recur.

If you have any further questions on the use of this product, ask your doctor or pharmacist.

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4. Possible Side Effects

Like all medicines, this medicine can cause side effects, although not everybody gets them.

If you experience any of the following, stop taking Furantoína and contact your doctor immediately or go to the emergency department of your nearest hospital:

  • Chest pain, cough, difficulty breathing.
  • Abdominal pain and jaundice (caused by liver inflammation) characterized by a yellowish color of the skin or the white part of the eyes.
  • Appearance of rashes, eruptions, blisters, or bubbles on the skin.
  • Swelling of lips, face, or tongue.
  • Loss of sensitivity in the hands or loss of muscle strength, confusion, weakness, blurred vision.

These are serious side effects that may require urgent medical attention or hospitalization.

When taking Furantoína, you may experience one or more of the following side effects:

Common

(may affect up to 1 in 100 people)

  • Allergic reactions on the skin (itching, hives).
  • Pseudo-lupus manifestations (fever, chills, and joint pain).
  • Angioedema (swelling of lips, face, or tongue).
  • Dizziness.
  • Peripheral neuropathies (loss of sensitivity in the hands or loss of muscle strength).
  • Nausea, vomiting, abdominal pain, diarrhea. Administration of nitrofurantoin with food reduces these effects.

Uncommon

(may affect up to 1 in 1,000 people)

  • Leukopenia, thrombocytopenia, and aplastic anemia, affecting blood cells (reduction in the number of white blood cells or platelets). Due to this, you may experience bruising and delayed coagulation. These blood cells usually return to normal levels after stopping treatment.
  • Collapse and cyanosis, which is a lack of oxygen in the blood that manifests externally as a bluish discoloration of the skin and mucous membranes.
  • Skin diseases: Cutaneous eruptions and exfoliative dermatitis (inflammation of the skin with or without scaling), erythema multiforme, and Stevens-Johnson syndrome (appearance of blisters or bubbles on the skin).

Rare

(may affect up to 1 in 10,000 people)

  • Acute pneumopathies, which are a type of lung disease characterized by fever, chills, cough, chest pain, and difficulty breathing. These symptoms disappear after stopping the antibiotic.
  • Cytolytic hepatitis and cholestatic hepatitis, inflammation of the liver with abdominal pain and appearance of jaundice (yellowish color of the skin or the white part of the eyes).

Frequency Not Known

  • Agranulocytosis, granulocytopenia, hemolytic anemia, megaloblastic anemia, glucose-6-phosphate dehydrogenase deficiency anemia, which are blood disorders characterized by the reduction and/or absence of one or more blood cells.
  • Eosinophilia, which is the presence of an abnormally high number of eosinophils, a type of blood cell.
  • Anaphylaxis (generalized allergic reaction that can be potentially severe), sialadenitis (inflammation of the salivary glands), pancreatitis (inflammation of the pancreas).
  • Inflammation of the walls of small blood vessels, causing skin lesions with an unknown frequency.
  • Fever and arthralgia (joint pain).
  • Depression, euphoria, and psychotic reactions.
  • Nystagmus (involuntary eye movements), vertigo (apparent sensation of spinning or movement), asthenia (feeling of fatigue, weakness, and physical and mental exhaustion), headache, and somnolence.
  • Anorexia (severe alteration of eating behavior).
  • Inflammation of the liver due to activation of the immune system against liver cells with an unknown frequency.
  • Inflammation of the kidney tissue surrounding the tubules, causing renal failure with an unknown frequency.

In very long treatments (more than 6 months) or in very frequent repeat treatments, very serious side effects such as:

  • Pulmonary fibrosis, which is a hardening of lung tissue with progressive loss of lung function.
  • Chronic active hepatitis (chronic liver inflammation), liver necrosis (death of liver cells), and fulminant hepatitis (the liver suddenly stops functioning).

Other Adverse Reactions

  • Transient alopecia (temporary hair loss), benign intracranial hypertension (increase in pressure within the cranial cavity, characterized by symptoms such as headache).
  • As with other antibiotics, superinfections by fungi or other microorganisms resistant to nitrofurantoin, such as Pseudomonasspp., may occur. These superinfections are limited to the genitourinary tract.

Reporting of Side Effects

If you experience any side effects, talk to your doctor, pharmacist, or nurse, even if it is a possible side effect not listed in this leaflet. You can also report side effects directly through the Spanish Pharmacovigilance System for Human Use Medicines: https://www.notificaram.es. By reporting side effects, you can help provide more information on the safety of this medicine.

5. Storage of Furantoína

Keep this medicine out of the sight and reach of children.

Store the blister pack in the outer packaging to protect it from light.

Do not use Furantoína after the expiry date stated on the packaging, after EXP. The expiry date is the last day of the month indicated.

Medicines should not be disposed of via wastewater or household waste. Place the packaging and any unused medicines in the SIGRE collection point at your pharmacy. If in doubt, ask your pharmacist how to dispose of the packaging and any unused medicines. This will help protect the environment.

6. Contents of the Pack and Further Information

Composition of Furantoína

Each tablet contains 50 mg of the active ingredient nitrofurantoin.

  • The other ingredients are: Povidone, sodium carboxymethylcellulose (type A) derived from potatoes, calcium hydrogen phosphate dihydrate, talc, magnesium stearate.

Appearance of the Product and Packaging

Round, yellow tablets, scored. The tablet can be divided into equal doses.

It is presented in PVC blisters sealed with a heat-sealable aluminum foil in packs of 21, 42 tablets, and 500 tablets (clinical packaging).

Marketing Authorization Holder

LABORATORIOS ERN, S.A.

Perú, 228 - 08020 Barcelona, Spain

Manufacturers

Laboratorios ERN, S.A.

Gorcs i Lladó, 188 – 08210 Barberá del Vallés. Barcelona. Spain.

Date of Last Revision of this Leaflet: February 2019

Detailed and updated information on this medicine is available on the website of the Spanish Agency for Medicines and Health Products (AEMPS) http://www.aemps.gob.es/

Online doctors for FURANTOIN 50 mg TABLETS

Discuss questions about FURANTOIN 50 mg TABLETS, including use, safety considerations and prescription review, subject to medical assessment and local regulations.

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Tarek Agami

General medicine 11 years exp.

Dr. Tarek Agami is a general practitioner registered in both Portugal and Israel, with broad experience in family and preventive medicine. He offers online consultations for adults and children, providing personalised support for primary care needs, chronic disease management, and everyday health concerns.

Dr. Agami received clinical training and worked in leading medical institutions in Israel (Kaplan Medical Center, Barzilai Medical Center, Wolfson Medical Center) and Portugal (European Healthcare City, Viscura Internacional, Hospital Dr. José Maria Grande, Hospital Vila Franca de Xira). His approach combines international medical standards with individualised attention to each patient.

Main areas of consultation:

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  • Treatment adjustments and lifestyle recommendations based on your personal history
Dr. Agami provides medical support for patients using GLP-1 medications (such as Ozempic or Mounjaro) as part of a weight loss strategy. He offers individualised treatment planning, regular follow-up, dose adjustment, and advice on combining medication with sustainable lifestyle changes. Consultations follow the medical standards accepted in Portugal and Israel.

Dr. Agami is committed to evidence-based, patient-centred care, ensuring that each person receives trusted medical support tailored to their health goals.

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Nuno Tavares Lopes

Family medicine 18 years exp.

Dr. Nuno Tavares Lopes is a licensed physician in Portugal with 17 years of experience in emergency medicine, family and general practice, and public health. He is the Director of Medical and Public Health Services at an international healthcare network and serves as an external consultant for the WHO and ECDC.

  • Emergency care: infections, fever, chest/abdominal pain, minor injuries, paediatric emergencies
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Dr. Nuno Tavares Lopes provides medical support for patients using GLP-1 medications (Mounjaro, Wegovy, Ozempic, Rybelsus) as part of a weight loss strategy. He offers individualised treatment planning, regular follow-up, dose adjustment, and advice on combining medication with sustainable lifestyle changes. Consultations follow the medical standards accepted in Europe.

Dr. Lopes also provides interpretation of medical tests, follow-up care for complex patients, and multilingual support. Whether for urgent concerns or long-term care, he helps patients act with clarity and confidence.

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Anastasiia Shalko

Family medicine 13 years exp.

Dr. Anastasiia Shalko is a general practitioner with a background in both paediatrics and general medicine. She graduated from Bogomolets National Medical University in Kyiv and completed her paediatric internship at the P.L. Shupyk National Medical Academy of Postgraduate Education. After working as a paediatrician in Kyiv, she relocated to Spain, where she has been practising general medicine since 2015, providing care for both adults and children.

Her work focuses on urgent, short-term medical concerns – situations where patients need quick guidance, symptom assessment and clear next steps. She helps people understand whether their symptoms require in-person evaluation, home management or a change in treatment. Common reasons for booking an online consultation include:

  • acute respiratory symptoms (cough, sore throat, runny nose, fever)
  • viral illnesses such as colds and seasonal infections
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  • sudden changes in how a child or adult feels
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Dr. Shalko works specifically with urgent and short-term problems, providing practical recommendations and helping patients determine the safest next step. She explains symptoms clearly, guides patients through decision-making and offers straightforward medical advice for everyday acute issues.

She does not provide long-term management of chronic conditions, ongoing follow-up or comprehensive care plans for complex long-term illnesses. Her consultations are designed for acute symptoms, sudden concerns and situations where timely medical input is important.

With clinical experience in both paediatrics and general medicine, Dr. Shalko confidently supports adults and children. Her communication style is clear, simple and reassuring, helping patients feel informed and supported throughout the consultation.

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Tomasz Grzelewski

Dermatology 21 years exp.

Dr Tomasz Grzelewski is an MD, PhD specialist in allergy, paediatrics, general practice and sports medicine, with a clinical focus on dermatology, endocrinology, allergology and sports-related health. He has more than 20 years of clinical experience and completed his medical training at the Medical University of Łódź, where he defended his PhD thesis with distinction. His doctoral research was recognised by the Polish Society of Allergology for its innovative contribution to the field. Throughout his career, he has gained extensive expertise in diagnosing and managing a wide range of allergic and paediatric conditions, including modern allergen desensitisation techniques.

For five years, Dr Grzelewski served as the Head of two paediatric departments in Poland, managing complex clinical cases and leading multidisciplinary teams. He also worked in medical centres in the United Kingdom, gaining experience across both primary care and specialist environments. With over a decade of telemedicine experience, he has provided online consultations across Europe and is valued for his clear, structured and evidence-based medical guidance.

Dr Grzelewski is actively involved in clinical programmes focused on modern anti-allergic therapies. As a Principal Investigator, he leads research projects on sublingual and oral allergen desensitisation, supporting evidence-based progress in allergy treatment for both children and adults.

In addition to his background in allergology and paediatrics, he completed dermatology studies through the Cambridge Education Group (Royal College of Physicians of Ireland) and a Clinical Endocrinology course at Harvard Medical School. This advanced training enhances his ability to manage skin manifestations of allergies, atopic conditions, urticaria, endocrine-related symptoms and complex immunological reactions.

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Dr Tomasz Grzelewski is known for his clear communication style, structured medical approach and ability to explain treatment options in a concise and accessible way. His multidisciplinary background across allergy, paediatrics, dermatology and endocrinology allows him to provide safe, up-to-date and comprehensive care for patients of all ages.
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Daniel Cichi

Family medicine 24 years exp.

Dr Daniel Cichi is a family medicine doctor with over 20 years of clinical experience. He provides online consultations for adults, supporting patients with acute symptoms, chronic conditions, and everyday health concerns that require timely medical guidance.

His background includes work in emergency care, ambulance services, and family medicine, which allows him to assess symptoms quickly, identify warning signs, and help patients choose the safest next steps – whether that means home care, treatment adjustment, or in-person evaluation.

Patients commonly consult Dr Daniel Cichi for:

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Dr Cichi’s consultations are structured and practical. He focuses on clear explanations, risk assessment, and actionable recommendations, helping patients understand their symptoms and make informed decisions about their health.
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Frequently Asked Questions

Is a prescription required for FURANTOIN 50 mg TABLETS?
FURANTOIN 50 mg TABLETS requires a prescription in Spain. You can check with a doctor online whether this medicine may be appropriate for your situation.
What is the active substance in FURANTOIN 50 mg TABLETS?
The active ingredient in FURANTOIN 50 mg TABLETS is nitrofurantoin. This information helps identify medicines with the same composition but different brand names.
How much does FURANTOIN 50 mg TABLETS cost in pharmacies?
The average pharmacy price for FURANTOIN 50 mg TABLETS is around 3.61 EUR. Prices may vary depending on the manufacturer and dosage form.
Who manufactures FURANTOIN 50 mg TABLETS?
FURANTOIN 50 mg TABLETS is manufactured by Laboratorios Ern S.A.. Pharmacy brands and packaging may differ depending on the distributor.
Which doctors can assess the use of FURANTOIN 50 mg TABLETS online?
Doctors such as Family doctors, Psychiatrists, Dermatologists, Cardiologists, Endocrinologists, Gastroenterologists, Pulmonologists, Nephrologists, Rheumatologists, Hematologists, Infectious disease physicians, Allergists, Geriatricians, Paediatricians, Oncologists may assess whether FURANTOIN 50 mg TABLETS is appropriate, depending on your situation and local regulations. You can book an online consultation to discuss your symptoms and possible next steps.
What are the alternatives to FURANTOIN 50 mg TABLETS?
Other medicines with the same active substance (nitrofurantoin) include FURANTOIN 10 mg/ml ORAL SUSPENSION, APEL 600 mg FILM-COATED TABLETS, COLFINAIR 1 Million IU Powder for Solution for Nebulizer Inhalation. These may have different brand names or formulations but contain the same therapeutic ingredient. Always consult a doctor before switching or starting a new medicine.
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