Immufalk 100 mg film-coated tablets: detailed information

Package leaflet: Information for the user

Introduction

PACKAGE LEAFLET: INFORMATION FOR THE USER

Immufalk 100 mg film-coated tablets

Azathioprine

Read the entire 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 questions, ask your doctor or pharmacist.
This medicine has been prescribed for you only and must not be given to other people, even if they have the same symptoms as you. It could harm them.
If you experience any adverse reactions, consult your doctor or pharmacist, even if they are adverse reactions not listed in this leaflet. See section 4.

Leaflet contents

What Immufalk is and what it is used for
What you need to know before taking Immufalk
How to take Immufalk
Possible adverse effects
How to store Immufalk
Contents of the container and other information

1. What Immufalk is and what it is used for

Immufalk contains the active substance azathioprine, which belongs to a group of medicines called immunosuppressants, which reduce the activity of your immune system.

Immufalk may be used to help your body accept a transplanted organ, such as a new kidney, heart, or liver, or to treat certain conditions in which your immune system is reacting against your own body (autoimmune diseases).

Immufalk may also be used alone or in combination with other medicines to treat:

Severe rheumatoid arthritis (a condition in which the immune system attacks the cells lining the joints, causing joint swelling, pain, and stiffness)
Severe inflammatory bowel disease (Crohn's disease or ulcerative colitis)
Systemic lupus erythematosus (a disease in which the immune system attacks many of the body's organs and tissues, including the skin, joints, kidneys, brain, and other organs, causing severe fatigue, fever, joint stiffness, and pain)
Dermatomyositis and polymyositis (a group of disorders causing muscle inflammation, muscle weakness, and skin rash)
Chronic active autoimmune hepatitis (a condition in which the immune system attacks liver cells, causing liver inflammation, fatigue, muscle aches, yellowing of the skin, and fever)
Polyarteritis nodosa (a rare disease causing inflammation of the blood vessels)
Autoimmune haemolytic anaemia (a serious blood disorder in which the immune system destroys red blood cells faster than they can be produced, resulting in symptoms such as weakness and shortness of breath)
Chronic refractory idiopathic thrombocytopenic purpura (a disorder characterized by low platelet counts, which may lead to easy or excessive bruising and bleeding)

Your doctor has chosen this medicine specifically for you and your condition.

Immufalk may be used alone, but it is more commonly used in combination with other medicines.

It may take weeks or months before a therapeutic effect is observed.

2. What you need to know before taking Immufalk

Do not take Immufalk

If you are allergic to azathioprine, mercaptopurine, or any of the other ingredients of this medicine (listed in section 6).
An allergic reaction may include rash, itching, difficulty breathing, or swelling of the face, lips, throat, or tongue.
If you have a severe infection
If you have a severe disorder of the liver or bone marrow
If you have pancreatitis (inflammation of the pancreas)
If you have recently been vaccinated with a live attenuated vaccine, such as smallpox or yellow fever
If you are pregnant (unless your doctor tells you otherwise)
If you are breastfeeding

Warnings and precautions

Talk to your doctor before starting to take Immufalk.

You should not take Immufalk unless you can be monitored for adverse effects. You must inform your doctor immediately if you develop throat ulcers, fever, infections, bruising, or bleeding.

Contact your doctor immediately:

if you notice any of the following signs: black (tarry) stools, blood in stools, abdominal pain, or yellowing of the skin or whites of the eyes (jaundice);

Talk to your doctor before starting Immufalk:

if you have recently received or are due to receive a vaccine. If you are taking Immufalk, you must not receive a live attenuated vaccine (e.g., influenza vaccine, measles vaccine, BCG vaccine, etc.) until your doctor confirms it is safe to do so. This is because some vaccines may cause infection if administered while you are taking Immufalk.
if you have liver or kidney problems
if you have a genetic disorder called TPMT deficiency (in which your body produces too little of an enzyme called thiopurine methyltransferase)
if you are scheduled for surgery (because drugs such as tubocurarine or succinylcholine, used as muscle relaxants during surgery, may interact with Immufalk). You must inform your anaesthesiologist about your treatment with Immufalk before surgery.
if you have a known genetic disorder called Lesch-Nyhan syndrome. This is a rare inherited condition caused by deficiency of HPRT (hypoxanthine-guanine phosphoribosyltransferase).

Liver injury

Treatment with Immufalk may affect the liver, and your doctor will periodically monitor your liver function. Inform your doctor if you experience symptoms of liver damage (see section 4 “Possible side effects”).

Infections

When receiving treatment with Immufalk, the risk of viral, fungal, and bacterial infections is increased, and these infections may be more severe. See also section 4.

Before starting treatment, inform your doctor if you have ever had chickenpox, herpes, or hepatitis B (a liver disease caused by a virus). While taking Immufalk, avoid contact with people who have chickenpox or shingles.

Vitamin B3 deficiency (pellagra)

Inform your doctor immediately if you experience diarrhoea, pigmented skin rash, and impaired memory, reasoning, or thinking, as these symptoms may indicate vitamin B3 deficiency (niacin deficiency/pellagra).

NUDT15 gene mutation

If you have an inherited mutation in the NUDT15 gene (a gene involved in breaking down azathioprine in the body), you have a higher risk of infections and hair loss, and in this case your doctor may prescribe a lower dose.

Your doctor may also perform genetic testing (e.g., testing your TPMT and/or NUDT15 genes) before or during treatment to determine whether your response to this medicine may be affected by your genetics. Your doctor may adjust your azathioprine dose based on these test results.

If you are receiving immunosuppressive therapy, taking Immufalk may increase your risk of:

Tumours, including skin cancer. Therefore, while taking Immufalk, avoid excessive sun exposure, wear protective clothing, and use high-protection sunscreens.
Lymphoproliferative disorders
- Treatment with Immufalk increases your risk of a type of cancer called lymphoproliferative disorder. When used in combination with other immunosuppressants (including thiopurines), this may be fatal.
- The combination of multiple immunosuppressants administered simultaneously increases the risk of lymphatic system disorders due to viral infection (Epstein-Barr virus (EBV)-associated lymphoproliferative disorders).
Reactivation of a previous hepatitis B virus infection
Other infections such as PML (progressive multifocal leukoencephalopathy), which is an opportunistic infection. If you experience any signs of infection, contact your doctor (see section 4 “Possible side effects”).

Taking Immufalk may increase your risk of:

developing a serious condition called macrophage activation syndrome (excessive activation of white blood cells associated with inflammation), which typically occurs in people with certain types of arthritis.

If you are unsure whether any of the above applies to you, speak with your doctor, nurse, or pharmacist before taking Immufalk.

Blood tests

You will need to have a blood test once a week during the first 8 weeks of treatment. You may need more frequent blood tests if:

you are elderly
you are taking a high dose
you have bone marrow disorders
you have an overactive spleen
you have kidney dysfunction. Your doctor may reduce your dose if necessary
you have liver dysfunction. Your doctor will regularly monitor your liver function and may reduce your dose if necessary
you are taking other medications that may harm the liver

It is important to use effective contraception (such as condoms), as Immufalk may cause birth defects whether taken by the man or the woman.

Other medicines and Immufalk

Tell your doctor or pharmacist if you are taking, have recently taken, or might need to take any other medicines. This is because Immufalk may affect how some medicines work. Also, other medicines may affect how Immufalk works. In particular, inform your doctor if you are taking or plan to take:

allopurinol, oxipurinol, thiopurinol, or other xanthine oxidase inhibitors such as febuxostat (mainly used to treat gout)
other immunosuppressants such as cyclosporine or tacrolimus
infliximab (mainly used to treat ulcerative colitis and Crohn’s disease)
aminosalicylates, e.g., olsalazine, mesalazine, or sulfasalazine (mainly used to treat ulcerative colitis and Crohn’s disease)
warfarin or phenprocoumon (to thin the blood)
ACE inhibitors (used to treat high blood pressure or heart failure)
cimetidine (used to treat stomach ulcers and indigestion)
indomethacin, cyclophosphamide, chlorambucil, melphalan (used to treat rheumatoid arthritis)
cancer treatments or treatments that slow or stop the production of new blood cells
co-trimoxazole (an antibiotic used to treat bacterial infections)
ribavirin, peginterferon (used to treat viral infections)
methotrexate (mainly used to treat cancers)
furosemide (a diuretic used to treat heart failure)
vaccines, such as hepatitis B vaccine
any “live” vaccine
muscle relaxants, e.g., tubocurarine or succinylcholine (used during surgery), as they may interact with Immufalk. You must inform your anaesthesiologist about your Immufalk treatment before surgery.

If you are unsure whether any of the above applies to you, speak with your doctor or pharmacist before taking Immufalk.

Receiving vaccines while taking Immufalk

If you need to receive a vaccine, talk to your doctor or nurse first. If you are taking Immufalk, you must not receive a live attenuated vaccine (e.g., influenza vaccine, measles vaccine, BCG vaccine, etc.) until at least 3 months after stopping treatment or until your doctor confirms it is safe. This is because some vaccines may cause infection if administered while you are taking Immufalk. If you need inactivated vaccines, your doctor may need to monitor your immune response.

Immufalk with food and drinks

You should take your medicine at least 1 hour before or 2 hours after consuming milk or dairy products.

Pregnancy and breastfeeding

If you are pregnant or breastfeeding, think you may be pregnant, or plan to become pregnant, consult your doctor or pharmacist before taking this medicine.

Do not take Immufalk if you are pregnant unless your doctor instructs you to do so. Inform your doctor if you are pregnant or think you might be. Both male and female patients of reproductive age should use contraception methods other than intrauterine devices (e.g., copper coil or IUD).

Contraception should continue for 6 months after stopping Immufalk treatment. If you have fertility problems due to chronic uraemia, note that fertility usually returns to normal after transplantation, and contraception should be used.

You must not breastfeed during treatment with Immufalk, as metabolites formed in the body pass into breast milk and may harm the infant.

Inform your doctor immediately if you experience intense itching without a rash during pregnancy. You may also experience nausea and loss of appetite along with itching, which may indicate a condition called cholestasis of pregnancy (a liver disorder during pregnancy). This condition may harm the foetus.

Driving and using machines

It is safe to drive or operate machinery while taking Immufalk unless you feel dizzy. Dizziness may be worsened by alcohol, so do not drive or operate machinery if you have consumed alcohol.

Immufalk contains lactose

This medicine contains lactose. If your doctor has told you that you have an intolerance to certain sugars, consult with him before taking this medicine.

This medicine contains less than 1 mmol of sodium (23 mg) per tablet; essentially “sodium-free”.

3. How to take Immufalk

Follow exactly the instructions given by your doctor or pharmacist for taking this medicine. If you are unsure, consult your doctor or pharmacist again.

The amount of Immufalk may vary from patient to patient and will be prescribed by your doctor. The dose depends on the condition for which you are being treated.

You may take Immufalk with food or on an empty stomach, but you must use the same method every day. Some patients experience nausea when first taking Immufalk, which may be relieved by taking the tablets after meals.

While taking Immufalk, your doctor will perform regular blood tests. These are to check the number and types of blood cells present and to ensure your liver is functioning properly.

Your doctor may also request additional blood and urine tests to monitor kidney function and measure uric acid levels. Uric acid is a natural substance produced in your body, and uric acid levels may increase while taking Immufalk. High levels of uric acid can damage your kidneys.

Occasionally, your doctor may adjust your dose of Immufalk based on the results of these tests.

Swallow the tablets whole with plenty of liquid (at least 200 ml). Do not chew the tablets. The tablets must not be broken or crushed.

It is important that caregivers are aware of the need to handle this medicine safely. If you or your caregiver handle broken tablets, wash your hands immediately. Consult your doctor or pharmacist for advice.

Dosage

Adults who have received an organ transplant: on the first day of treatment, the usual dose is up to 5 mg per kilogram of body weight, and subsequently the usual daily dose is between 1 mg and 4 mg per kilogram of body weight. During treatment, your doctor will adjust the dose according to your response to the medicine.

Adults with other disorders: the usual initial dose is between 1 mg and 3 mg per kilogram of body weight, and subsequently the usual daily dose is less than between 1 mg and 3 mg per kilogram of body weight. During treatment, your doctor will adjust the dose according to your response to the medicine.

Use in children and adolescents

Immufalk is not recommended for use in individuals under 18 years of age due to insufficient data on the treatment of juvenile chronic arthritis, systemic lupus erythematosus, dermatomyositis, and polyarteritis nodosa.

For other indications, the same dosage recommendations apply in children and adolescents as in adults.

Children considered overweight may require a higher dose.

Elderly patients:

Elderly patients may require a reduced dose.

Patients with liver or kidney disorders may need a reduced dose.

Patients with severe liver problems must not take Immufalk.

Your doctor will decide the duration of treatment with Immufalk.

If you think the effect of Immufalk is too strong or too weak, please consult your doctor.

If you take more Immufalk than you should

Contact your doctor, pharmacist, or nearest hospital immediately.

In case of overdose or accidental ingestion, contact your doctor or pharmacist immediately or call the Toxicology Information Service at telephone number 915 620 420, stating the medicine and the amount ingested.

If you forget to take Immufalk

Do not take a double dose to make up for the dose you missed. Inform your doctor if you miss a dose. If it is almost time for your next dose, skip the missed dose and take the next dose at the scheduled time. Otherwise, take it as soon as you remember, and then continue taking your doses as usual.

If you stop taking Immufalk

Any discontinuation of Immufalk should be done gradually and under careful monitoring. Please consult your doctor.

If you have any further questions about using this product, ask your doctor or pharmacist.

4. Possible adverse effects

Like all medicines, this medicine can cause adverse effects, although not everyone experiences them.

Serious adverse effects:

If you experience any of the following serious adverse effects, consult your doctor or go to a hospital immediately:

If you suddenly develop ringing in the ears, difficulty breathing, swelling of the eyelids, face or lips, rash or itching (especially if affecting the whole body).
Allergic reaction, signs of which may include: general fatigue, dizziness, nausea, vomiting or diarrhea, fever, chills, skin redness, skin nodules or rash, muscle or joint pain, changes in urine color (kidney problems), chest pain, difficulty breathing or swollen legs (heart problems), confusion, feeling dizzy or weak (caused by low blood pressure).
Severe potentially fatal liver damage, especially in patients receiving long-term treatment (such as liver injury, non-cirrhotic portal hypertension, portosinusoidal vascular disease). Inform your doctor if you experience any of the following symptoms: yellowing of the skin and whites of the eyes (jaundice), easy bruising, abdominal discomfort, loss of appetite, fatigue, nausea, or vomiting.
Reversible swelling of the brain with symptoms such as severe headache, vision disturbances, seizures, confusion and decreased level of consciousness, with or without high blood pressure (posterior reversible encephalopathy syndrome or PRES).

Contact your doctor immediately if you develop any of the following adverse effects:

muscle or bone pain, muscle stiffness
inflammation of blood vessels
kidney disorders (symptoms may include changes in the amount of urine and changes in its color)
high temperature (fever) or other signs of infection such as sore throat, mouth sores, urinary problems or chest infection causing difficulty breathing and cough

The following adverse effects have also been reported:

Very common: may affect more than 1 in 10 users
- infections caused by viruses, fungi or bacteria in patients who have received a transplant
- blood and bone marrow problems, with signs such as weakness, fatigue, paleness, easy bruising, unusual bleeding or infections
Common: may affect up to 1 in 10 users
- low platelet count, which may lead to bruising or bleeding
- nausea and vomiting, loss of appetite (anorexia)
Uncommon: may affect up to 1 in 100 users
- infections caused by viruses, fungi or bacteria in all patients except those who have received a transplant
- low red blood cell count, which may cause fatigue, headaches, shortness of breath during exercise, dizziness and paleness
- allergic reactions, which may cause general discomfort, dizziness, malaise, vomiting, diarrhea, fever, chills, skin reactions such as rash, skin nodules and eruptions, inflammation of blood vessels, muscle and joint pain, low blood pressure, kidney or liver disorders and intestinal problems
- inflammation of the pancreas, which may cause severe upper abdominal pain with nausea and vomiting
- liver abnormalities, which may result in pale stools, dark urine, itching and yellowing of the skin and eyes, and abnormalities in liver function tests
- cholestasis of pregnancy, a buildup of bile causing liver inflammation that may lead to severe itching, especially in the hands and feet
Rare: may affect up to 1 in 1,000 users
- blood and bone marrow disorders that may cause weakness, fatigue, paleness, headaches, tongue pain, shortness of breath, bruising or infections
- intestinal disorders causing diarrhea, abdominal pain, constipation and discomfort (nausea and vomiting)
- severe potentially fatal liver damage
- hair loss that may improve even while continuing to take Immufalk tablets
- various types of cancer, including skin cancer, blood cancer and lymphomas

Very rare: may affect up to 1 in 10,000 users

skin rashes or redness, which may progress to potentially life-threatening skin reactions, including widespread blistering rash and skin peeling, especially around the mouth, nose, eyes and genitals (Stevens-Johnson syndrome), extensive skin peeling (toxic epidermal necrolysis)
sudden and severe allergic reaction with difficulty breathing, swelling, dizziness, rapid heartbeat, sweating and loss of consciousness
intestinal problems causing diarrhea, abdominal pain, constipation, nausea or vomiting (intestinal perforation)
lung inflammation causing difficulty breathing, cough and fever
if Immufalk is used in combination with other immunosuppressants, you may contract a virus that damages your brain. This may cause headaches, changes in behavior, speech problems and worsening of skills such as memory, attention and decision-making (cognitive decline), and may be fatal (a disorder known as JC virus-associated progressive multifocal leukoencephalopathy)
irregular and uncoordinated contractions of the upper chambers of the heart (atrial fibrillation)

Frequency not known: cannot be estimated from available data

You may develop a skin rash (raised red, pink or purple painful bumps), especially on your arms, hands, fingers, face and neck, which may also be accompanied by fever (Sweet's syndrome, also known as acute febrile neutrophilic dermatosis)
photosensitivity (sensitivity to light or sunlight)
a certain type of lymphoma (hepatosplenic T-cell lymphoma). You may experience nosebleeds, fatigue, severe night sweats, weight loss and unexplained fever (high temperature)
excessive breakdown of red blood cells causing fatigue and pale skin (hemolytic anemia), excess eosinophils (a type of white blood cell) (eosinophilia)
excessive activation of macrophages and T-lymphocytes causing hyperinflammation and cytokine storm associated with cytomegalovirus disease and Epstein-Barr virus infection
drug hypersensitivity reaction with eosinophilia and systemic symptoms (DRESS)
vitamin B3 deficiency (pellagra) associated with localized pigmented skin rash, diarrhea and decreased memory, reasoning ability or other mental functions
acute generalized exanthematous pustulosis (AGEP)
severe liver damage (such as liver injury, non-cirrhotic portal hypertension or portosinusoidal vascular disease)
burning or tingling sensation in the mouth or lips (mucosal inflammation, stomatitis)
cracked or swollen lips (cheilitis)
decreased coagulation factors
inflammation of the salivary glands (sialoadenitis)
tremor

Reporting of adverse effects

If you experience any adverse effects, consult your doctor or pharmacist, even if they are adverse effects not listed in this leaflet. You may also report them directly via the Spanish Pharmacovigilance System for Human Medicines: www.notificaRAM.es. By reporting adverse effects, you can help provide more information on the safety of this medicine.

5. Storage of Immufalk

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

Store in the original container to protect it from light.

Do not use Immufalk after the expiry date stated on the packaging and on the blister after "EXP". The expiry date refers to the last day of the month indicated.

Do not use Immufalk if you notice any visible signs of deterioration.

Medicines must not be disposed of via wastewater or household waste. Dispose of empty containers and unused medicines at the SIGRE point located at your pharmacy. If in doubt, ask your pharmacist how to properly dispose of containers and unused medicines. This way you will help protect the environment.

6. Contents of the pack and other information

Composition of Immufalk

The active substance is azathioprine.

Each film-coated tablet contains 100 mg of azathioprine.

The other components (excipients) are:

Tablet core: croscarmellose sodium, colloidal anhydrous silica, lactose monohydrate, microcrystalline cellulose, sodium stearyl fumarate, pregelatinized maize starch, povidone K25.

Film coating: macrogol 3350, polysorbate 80, poly(vinyl alcohol), talc.

Appearance of the product and contents of the pack

Immufalk 100 mg film-coated tablets are yellow, round, biconvex tablets, 10.0 mm in diameter, marked with “100” on one side.

The tablets must not be crushed. If the tablet coating is damaged or the tablet is completely crushed, avoid skin contamination or inhalation of tablet particles. For appropriate long-term dosing, other medicinal products containing 25 mg should be used if necessary.

Pack sizes:

Film-coated tablets are packed in PVC/aluminum blisters in cardboard boxes.

Immufalk 100 mg tablets are available in pack sizes of: 20, 30, 50, 60, 90 or 100 film-coated tablets.

Only certain pack sizes may be marketed.

Marketing Authorization Holder and Manufacturer

Dr. Falk Pharma GmbH
Leinenweberstr. 5
79108 Freiburg
Germany
Tel +49 (0) 761 / 1514-0
Fax +49 (0) 761 / 1514-321
E-mail: [email protected]

Further information on this medicinal product is available from the local representative of the Marketing Authorization Holder:

Dr. Falk Pharma España
Camino de la Zarzuela, 21
28023 Madrid
Spain
Tel +34 91 3729508

This medicinal product is authorized in the Member States of the European Economic Area under the following names:

Germany and Portugal: Azafalk.
Spain: Immufalk.

Date of the most recent revision of this leaflet: November 2025

Detailed and up-to-date information on this medicinal product is available on the website of the Spanish Agency of Medicines and Medical Devices (AEMPS): http://www.aemps.es/

The following information is intended for medical or healthcare professionals only:

Immufalk 75 mg film-coated tablets

Instructions for handling and disposal

There are no risks associated with handling tablets with intact film coating. In this case, no special safety precautions are required.

However, if the film-coated tablets have been crushed, Immufalk film-coated tablets must be handled strictly in accordance with the guidelines for handling cytotoxic agents. Any surplus medicinal products as well as contaminated devices must be temporarily stored in clearly labeled containers. Any unused product or waste material must be disposed of in accordance with local requirements.