METAMIZOLE KALCEKS 500 mg/mL Injectable Solution

2. What you need to know before taking Metamizol Kalceks

Do not use Metamizol Kalceks:

• if you are allergic to metamizol or other related substances (e.g., phenazone, propyphenazone, phenylbutazone, oxyphenbutazone) or to any of the other ingredients of this medicine (listed in section 6);
• • if you have previously had a significant decrease in a type of white blood cell called granulocytes, which was caused by metamizol or other similar medicines called pyrazolones or pyrazolidines;
  • if you have low blood pressure or circulation problems;
  • if you have bone marrow problems or a disorder that affects the way your blood cells are produced or function;
  • if you have ever had asthma or allergic reactions associated with taking painkillers (salicylates, paracetamol, or other painkillers, e.g., diclofenac, ibuprofen, indomethacin, or naproxen), such as hives or swelling of the face and mucous membranes of the respiratory or digestive tract;
  • if you currently have a severe liver disease, such as porphyria (risk of triggering porphyria attacks);
  • if you have a genetic deficiency of glucose-6-phosphate dehydrogenase (risk of red blood cell breakdown);
  • if you are in the last three months of pregnancy.

Warnings and precautions

Consult your doctor, pharmacist, or nurse before starting to use Metamizol Kalceks.

Be particularly careful with metamizol:

• If you experience fever, chills, sore throat, or mouth sores, consult your doctor immediately. These symptoms may be due to neutropenia (low white blood cell count).
• Consult your doctor immediately if you experience signs and symptoms that suggest blood disorders (e.g., general weakness, infection, persistent fever, bruising, bleeding). This may be due to a condition called pancytopenia (reduction in the number of all types of blood cells).
• If you have asthma or atopy (a type of allergy). In these cases, there is a higher risk of anaphylactic shock (a life-threatening allergic reaction) (see Do not use Metamizol Kalceks).
• If you have any of the following disorders, as there is a higher risk of severe anaphylactic reactions to metamizol:
• • bronchial asthma and simultaneous rhinitis of the nasal mucosa;
  • prolonged or permanent hives;
  • hypersensitivity to alcohol, i.e., if you react even to small amounts of alcohol with symptoms such as sneezing, runny nose, and flushing of the face;
  • intolerance to colorants (e.g., tartrazine) or preservatives (e.g., benzoates).
• If you have low blood pressure, fluid loss, unstable fluid balance, or impending circulatory failure. In these cases, there is a higher risk of severe hypotensive reactions. Your doctor will carefully consider the administration of Metamizol Kalceks and, if this medicine is administered even in these circumstances, close medical supervision will be required. It is necessary to take preventive measures to reduce the risk of a severe hypotensive reaction. The administration of metamizol may cause hypotensive reactions even without association with the aforementioned diseases. These reactions seem to depend on the dose; your doctor will carefully consider the indications for a single dose greater than 1 g of metamizol.
• If you have severe coronary artery disease or have narrow blood vessels that supply the brain. In these cases, it is essential to avoid hypotension, and therefore, this medicine can only be administered under close monitoring of circulatory functions.
• If you have severe kidney or liver disease. In this case, you should not receive high doses of this medicine, as its secretion is reduced.

Low white blood cell count (agranulocytosis).

Metamizol Kalceks may cause agranulocytosis, a very low level of a type of white blood cell called granulocytes, which are important for fighting infections (see section 4). You should stop taking metamizol and contact your doctor immediately if you experience any of the following symptoms, as they may indicate possible agranulocytosis: chills, fever, sore throat, and painful sores in the mucous membranes (wet surfaces of the body), especially in the mouth, nose, and throat, or in the genital or anal area. Your doctor will perform laboratory tests to check your blood cell count.

If you take metamizol for fever, some symptoms of agranulocytosis may go unnoticed. Similarly, symptoms may be masked if you are taking antibiotics.

Agranulocytosis may occur at any time during the use of Metamizol Kalceks and even shortly after stopping metamizol.

You may develop agranulocytosis even if you have used metamizol without problems in the past.

Severe skin reactions

Severe skin reactions, such as Stevens-Johnson syndrome, toxic epidermal necrolysis, and drug reaction with eosinophilia and systemic symptoms (DRESS), have been reported in association with metamizol treatment. Stop using metamizol and seek medical attention immediately if you experience any of the symptoms related to these severe skin reactions described in section 4.

If you have ever had severe skin reactions, you should not restart treatment with Metamizol Kalceks at any time (see section 4).

Liver problems

Cases of liver inflammation have been reported in patients taking metamizol, with symptoms developing within a few days to a few months after starting treatment.

Stop using metamizol and contact your doctor if you experience symptoms of liver problems, such as discomfort (nausea or vomiting), fever, feeling tired, loss of appetite, dark urine, pale stools, yellowing of the skin or the white part of the eyes, itching, rash, or upper abdominal pain. Your doctor will check your liver function.

You should not take metamizol if you have previously taken a medicine containing metamizol and had liver problems.

Other medicines and Metamizol Kalceks

Tell your doctor if you are using, have recently used, or might use any other medicines. It is especially important if you use:

• bupropion, a medicine used to treat depression and/or help you quit smoking;
• efavirenz, a medicine used to treat HIV/AIDS;
• methadone, a medicine used to treat addiction to illicit drugs (opioids);
• valproate, a medicine used to treat epilepsy or bipolar disorder;
• tacrolimus, a medicine used to prevent organ rejection in transplant patients;
• sertraline, a medicine used to treat depression;
• cyclosporin, a medicine used to suppress the immune system.

If you are given Metamizol Kalceks with any of the aforementioned medicines, your doctor will carefully monitor you.

Concomitant administration of Metamizol Kalceks and methotrexate (a medicine used to suppress the immune system) may increase the side effects of methotrexate on blood cell production (hematotoxicity), particularly in elderly patients. It is preferable to avoid using this combination.

Cautious administration of this medicine with acetylsalicylic acid for the prevention of heart attacks is recommended.

Pregnancy and breastfeeding

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

Pregnancy

Available data on the use of metamizol during the first three months of pregnancy are limited but do not indicate harmful effects on the embryo. In selected cases where no other treatment options are available, single doses of metamizol during the first and second trimester may be acceptable after consulting your doctor or pharmacist and carefully evaluating the benefits and risks of using metamizol. However, in general, the use of metamizol is not recommended during the first and second trimester.

During the last three months of pregnancy, you should not take Metamizol Kalceks due to the increased risk of complications for the mother and the baby (bleeding, premature closure of a vital blood vessel for the fetus, called the ductus arteriosus, which closes naturally after birth).

Breastfeeding

Metamizol breakdown products are excreted in breast milk in significant amounts, and it cannot be excluded that there is a risk for the breastfed infant. Therefore, repeated use of metamizol during breastfeeding should be avoided. If a single dose of metamizol is administered, it is recommended that mothers express and discard breast milk for 48 hours after administration.

Driving and using machines

Using this medicine at the recommended doses will not affect your ability to drive or use machines.

Do not drive or use machines if you are taking higher doses of this medicine than recommended, especially in combination with alcohol, as your reaction and concentration abilities will be impaired.

Metamizol Kalceks contains sodium

This medicine contains less than 1 mmol of sodium (23 mg) per daily dose of up to 0.7 ml; i.e., it is essentially "sodium-free". If daily doses of 0.8 ml or more (equivalent to more than 1 mmol of sodium) are administered, the following should be considered: This medicine contains 32.71 mg of sodium (a major component of table salt/cooking salt) per ml of solution. This is equivalent to 1.64% of the maximum recommended daily sodium intake for an adult.

3. How to use Metamizol Kalceks

Follow the instructions for administration of this medicine exactly as indicated by your doctor or pharmacist. If you are unsure, consult your doctor or pharmacist again.

The dose and method of administration depend essentially on the desired analgesic effects and your state of health.

The dose is determined based on the intensity of the pain or fever and individual sensitivity to metamizol treatment.

The effect of the medicine usually appears 30 minutes after parenteral administration. The duration of action is usually around 4 hours.

This medicine will be administered to you in the form of an injection into a vein or muscle. When administered by injection, it is necessary to remain lying down after administration of the medicine and under the supervision of a doctor, who will monitor your health with due attention.

If the effect of a single dose is insufficient or later, when the analgesic effect has decreased, your doctor may administer another dose until the maximum daily dose indicated below is reached.

Adults and adolescents 15 years or older

Adults and adolescents 15 years of age or older (weighing more than 53 kg) may be administered 1 to 2 ml by intravenous or intramuscular route in a single dose; when necessary, the single dose may be increased up to 5 ml (corresponding to 2,500 mg of Metamizol Kalceks). The maximum daily dose is 8 ml; when necessary, the daily dose may be increased up to 10 ml (corresponding to 5,000 mg of Metamizol Kalceks).

Infants and children

The administration guideline for single doses by intravenous or intramuscular route is as follows:

Elderly patients and patients with poor general health/renal insufficiency

The dose should be reduced in elderly patients, debilitated patients, and those with reduced renal function, as the elimination of metamizol breakdown products may be delayed.

Patients with renal or hepatic insufficiency

Since the elimination rate decreases in cases of renal or hepatic insufficiency, repeated high-dose administration should be avoided. Only in short-term treatments is dose reduction not necessary. There is no experience with long-term treatments.

Use in children

See the above table for dosage.

The usual dose for fever treatment in children is 10 mg/kg body weight.

If you use more Metamizol Kalceks than you should

Symptoms of acute overdose include nausea, vomiting, abdominal pain, impaired renal function/acute renal failure, nervous system disorders (dizziness, drowsiness, coma, convulsions), hypotension, and abnormal heart rhythms. Administration of very high doses of metamizol may cause a red discoloration of the urine without harmful effects.

In case of overdose or accidental ingestion, consult your doctor or pharmacist immediately or call the Toxicology Information Service, phone: 91 562 04 20, indicating the medicine and the amount ingested.

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

4. Possible Adverse Effects

Like all medicines, this medicine can cause adverse effects, although not all people suffer from them.

Stop treatment immediatelyand contact your doctor or hospital if you experience any of the following side effects; they may be symptoms of agranulocytosis (decrease or disappearance of a type of white blood cell in the blood) (rare - may affect up to 1 in 1,000 people):

• Fever (that unexpectedly persists or recurs)
• Chills
• Sore throat
• Difficulty swallowing
• Mouth ulcers or lesions of other mucous membranes, e.g., nasal, genital, and anorectal.

The onset of agranulocytosis is unpredictable and can occur even when metamizole has been used previously without any complications. Agranulocytosis can be life-threatening and potentially fatal (see also Warnings and Precautions). The symptoms mentioned may be minimal in patients treated with antibiotics. The sedimentation of red blood cells increases greatly, while the enlargement of lymph nodes is moderate or nil.

Severe skin reactions

Stop using metamizole and seek medical attention immediatelyif you observe any of the following serious adverse effects (frequency not known: cannot be estimated from available data):

• Red patches that are not raised, or circular or target-shaped patches on the chest, often with central blisters, skin peeling, mouth ulcers, throat ulcers, nasal ulcers, genital ulcers, and eye ulcers. These severe skin rashes can be preceded by fever and flu-like symptoms (Stevens-Johnson syndrome, toxic epidermal necrolysis).
• Widespread redness, elevated body temperature, and enlarged lymph nodes (DRESS syndrome or drug hypersensitivity syndrome).

Stop using metamizole and contact a doctor immediatelyif you experience any of the following symptoms:

• Feeling unwell (nausea or vomiting), fever, feeling tired, loss of appetite, dark urine, pale stools, yellowing of the skin or the white part of the eyes, itching, rash, or pain in the upper abdomen. These symptoms may be signs of liver damage. See also section 2 Warnings and Precautions.

Inform your doctor if you experience any of the following adverse reactions or if you have any problems with the medication.

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

• Aplastic anemia (decrease in the number of red blood cells).
• Leukopenia (decrease in the number of white blood cells).
• Pancytopenia (decrease in the number of all blood cells).
• Thrombocytopenia (decrease in the number of platelets) (increased tendency to bleeding and presence of small brown-red spots (petechiae) on the skin and mucous membranes).
• Allergic reactions (anaphylactic/anaphylactoid).
• Anaphylactic shock (potentially fatal).

These reactions can occur during injection or a few hours (usually within an hour) after administration of the medicine. They can occur despite the fact that the repeated use of metamizole in the past has not led to any complications.

Moderate allergic reactions manifest with skin and mucous membrane symptoms (such as itching, burning, redness, urticaria, and swelling), respiratory difficulties, or, rarely, gastrointestinal symptoms. In the most severe cases, the symptoms can generalize, including severe angioedema (swelling of the face, lips, tongue, or throat that can cause difficulty swallowing or breathing), severe bronchospasm, difficulty breathing, cardiac arrhythmias, and low blood pressure, and can cause anaphylactic shock. In patients with bronchial asthma, these reactions manifest as an asthma attack.

• Skin rash

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

• Reversible renal dysfunction with decreased urine output (oliguria) or cessation (anuria), or acute renal failure, accompanied by protein excretion in the urine (proteinuria).

Frequency not known(cannot be estimated from available data):

• Kounis syndrome (cardiac condition due to an allergic reaction).
• Isolated and transient decrease in blood pressure, rarely critical, without other symptoms of hypersensitivity reaction. Rapid intravenous injection can increase the risk of such a hypotensive reaction.
• Kidney inflammation (interstitial nephritis).
• Pain at the injection site.
• Phlebitis.
• Liver inflammation, yellowing of the skin and the white part of the eyes, increased blood levels of liver enzymes.

Reporting of Adverse Effects

If you experience any type of adverse effect, consult your doctor, pharmacist, or nurse, even if it is a possible adverse effect that is not listed in this leaflet. You can also report them directly through the Spanish Pharmacovigilance System for Human Use Medicines: www.notificaRAM.es. By reporting adverse effects, you can contribute to providing more information on the safety of this medicine.

5. Storage of Metamizol Kalceks

Store in the original packaging to protect it from light. Do not freeze.

After opening the ampoule: the product must be used immediately.

Validity period after dilution

Chemical and physical stability has been demonstrated for 6 hours at 25°C when diluted with 0.9% sodium chloride solution or Ringer's solution.

Chemical and physical stability has been demonstrated for 20 minutes at 25°C when diluted with 5% glucose solution.

From a microbiological point of view, unless the dilution method prevents the risk of microbial contamination, the medicine should be used immediately. If not used immediately, the storage times and conditions prior to use are the responsibility of the user.

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

Do not use this medicine after the expiration date stated on the packaging after CAD. The expiration date is the last day of the month indicated.

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

6. Package Contents and Additional Information

Composition of Metamizol Kalceks

• The active ingredient is metamizole sodium monohydrate.

1 ml of solution contains 500 mg of metamizole sodium monohydrate.

Each ampoule (2 ml) contains 1,000 mg of metamizole sodium monohydrate.

Each ampoule (5 ml) contains 2,500 mg of metamizole sodium monohydrate.

• The other ingredients are: 1 M hydrochloric acid solution (for pH adjustment), water for injectable preparations.

Appearance and Package Contents

Injectable solution.

Clear solution, almost colorless to yellow-brown, practically without visible particles.

Solution of 2 or 5 ml in a topaz-colored glass ampoule.

5 ampoules are placed in a tray. 1, 2, or 20 trays are packaged in cardboard boxes.

Package sizes: 5, 10, or 100 ampoules.

Not all package sizes may be marketed.

Marketing Authorization Holder

AS KALCEKS

Krustpils iela 71E, Riga, LV-1057, Latvia

Manufacturer

Akciju sabiedriba “Kalceks”

Krustpils iela 71E, Riga, LV-1057, Latvia

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

Czech Republic Metamizole Kalceks

Austria, Germany Metamizol Kalceks 500 mg/ml Injektionslösung

Bulgaria Metamizole Kalceks 500 mg/ml ??????????? ???????

Croatia Metamizolnatrij hidrat Kalceks 500 mg/ml otopina za injekciju

Hungary Metamizole Kalceks 500 mg/ml oldatos injekció

Lithuania Metamizole sodium Kalceks 500 mg/ml injekcinis tirpalas

Poland Metamizole Kalceks

Romania Metamizol Kalceks 500 mg/ml solu?ie injectabila

Slovakia Metamizole Kalceks 500 mg/ml injekcný roztok

Slovenia Natrijev metamizolat Kalceks 500 mg/ml raztopina za injiciranje

Spain Metamizol Kalceks 500 mg/ml solución inyectable EFG

You can request more information about this medicine from the marketing authorization holder.

Date of the last revision of this leaflet:April 2025.

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/.

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This information is intended only for healthcare professionals:

It should be noted that parenteral administration is associated with a high risk of anaphylactic/anaphylactoid reactions.

It is necessary to ensure that the injection of the medicine is interrupted at the first sign of anaphylactic reaction and the risk of an isolated hypotensive reaction is minimized. During parenteral administration, it is necessary to ensure that the patient is in a horizontal position and under strict medical supervision. Additionally, in order to prevent a hypotensive reaction, the intravenous injection should be administered very slowly, i.e., no more than 1 ml (500 mg of metamizole) per minute.

The injectable solution can be diluted with 5% glucose solution, 0.9% sodium chloride solution, or Ringer's solution. Due to possible incompatibilities, the metamizole solution should not be administered with other injectable medicines.