Metamizole Kalceks

Leaflet accompanying the packaging: information for the user

Metamizole Kalceks, 500 mg/ml, solution for injection

Metamizolum natricum monohydricum
Metamizole Kalceks may cause a severely decreased number of white blood cells (agranulocytosis),
which can lead to severe and life-threatening infections (see section 4).
You should stop taking the medicine and contact your doctor immediately if you experience
any of the following symptoms: fever, chills, sore throat, painful mouth ulcers,
or genital or anal ulcers.
If the patient has ever had agranulocytosis while taking metamizole or similar medicines,
they should never take this medicine again (see section 2).

You should carefully read the contents of the leaflet before taking the medicine, as it contains important information for the patient.

• You should keep this leaflet, so you can read it again if you need to.
• If you have any doubts, you should consult your doctor, pharmacist, or nurse.
• This medicine has been prescribed specifically for you. Do not pass it on to others. The medicine may harm them, even if their symptoms are the same.
• If you experience any side effects, including those not listed in this leaflet, you should tell your doctor, pharmacist, or nurse. See section 4.

Table of contents of the leaflet

• 1. What is Metamizole Kalceks and what is it used for
• 2. Important information before taking Metamizole Kalceks
• 3. How to take Metamizole Kalceks
• 4. Possible side effects
• 5. How to store Metamizole Kalceks
• 6. Contents of the packaging and other information

1. What is Metamizole Kalceks and what is it used for

Metamizole Kalceks contains the active substance metamizole, which is a pain-relieving, antipyretic, and spasmolytic medicine.
Metamizole Kalceks is used to treat:

• sudden, severe, or prolonged pain;
• fever, when other treatments are ineffective.

2. Important information before taking Metamizole Kalceks

When not to take Metamizole Kalceks

• in pregnant women in the third trimester.

Warnings and precautions

Before starting treatment with Metamizole Kalceks, you should discuss it with your doctor, pharmacist,
or nurse.
You should be particularly careful when taking Metamizole Kalceks:

• If you experience fever, chills, sore throat, or mouth ulcers, you should immediately consult your doctor. These symptoms may be associated with neutropenia (low white blood cell count).
• If you experience any symptoms indicating blood disorders (e.g., general weakness, infection, persistent fever, bruising, bleeding, or pallor), you should immediately consult your doctor. These symptoms may be caused by pancytopenia (reduced number of all blood cell types).
• If you have asthma or atopy (a type of allergy). In these cases, there is an increased risk of anaphylactic shock (a life-threatening allergic reaction) (see section "When not to take Metamizole Kalceks").
• If you have any of the following conditions, due to the increased risk of a severe anaphylactoid reaction to metamizole:
• asthma with concurrent rhinitis;
• prolonged or persistent hives;
• alcohol intolerance, i.e., patients who react to even small amounts of alcohol with sneezing, tearing, and facial flushing;
• allergy to dyes (e.g., tartrazine) or preservatives (e.g., benzoates).
• If you have low blood pressure, fluid loss, unstable fluid volume, initial stage of circulatory disorders, or high fever. There is an increased risk of severe hypotension (associated with a drop in blood pressure). The doctor will carefully consider the introduction of treatment with Metamizole Kalceks and, if administered, will do so under close supervision. It is necessary to take appropriate measures to minimize the risk of severe hypotension. Administration of metamizole may cause these reactions even without the coexistence of the above conditions. These reactions seem to be dose-dependent. The doctor will carefully consider the indications for the use of a single dose of metamizole greater than 1 g.
• If you have severe coronary artery disease or significant narrowing of the blood vessels supplying the brain. In these cases, it is absolutely necessary to avoid hypotension and therefore, in such a situation, metamizole may be administered only under close monitoring of circulatory parameters.
• If you have kidney or liver disease. In these cases, high doses of metamizole should not be used due to reduced elimination.

Agranulocytosis (severely decreased number of white blood cells)
Metamizole Kalceks may cause agranulocytosis, a severely decreased number of a certain type of white blood cells called granulocytes, which play an important role in fighting infections (see section 4). You should stop taking metamizole and immediately consult your doctor if you experience any of the following symptoms, as they may indicate possible agranulocytosis: chills, fever, sore throat, and painful mouth ulcers, especially in the mouth, nose, and throat or in the genital or anal area.
Your doctor will order a laboratory test to check your blood cell count.
If metamizole is taken for fever, some symptoms of developing agranulocytosis may remain unnoticed. Similarly, symptoms may also be masked if the patient is taking antibiotics.
Agranulocytosis may develop at any time during treatment with Metamizole Kalceks, and even for a short time after stopping metamizole.
Agranulocytosis may occur even if metamizole was previously administered without complications.
Severe skin reactions
Severe skin reactions, including Stevens-Johnson syndrome, toxic epidermal necrolysis, and drug rash with eosinophilia and systemic symptoms (DRESS syndrome), have been reported with metamizole treatment. If you experience any of these severe skin reactions, you should stop taking metamizole and immediately seek medical attention.
If you have ever had severe skin reactions, you should never take Metamizole Kalceks again (see section 4).
Liver disorders
Patients taking metamizole have experienced liver inflammation, with symptoms appearing within a few days to several months after starting treatment.
You should stop taking Metamizole Kalceks and consult your doctor if you experience any liver disorders, such as: feeling unwell (nausea or vomiting), fever, fatigue, loss of appetite, dark urine, pale stools, yellowing of the skin or whites of the eyes, itching, rash, or pain in the upper abdomen. Your doctor will check your liver function.

Metamizole Kalceks and other medicines

You should tell your doctor about all medicines you are currently taking or have recently taken, as well as any medicines you plan to take. This is especially important if you are taking:

• bupropion, a medicine used to treat depression or to help quit smoking;
• efavirenz, a medicine used to treat HIV infection (AIDS);
• methadone, a medicine used to treat opioid addiction;
• valproate, a medicine used to treat epilepsy or bipolar disorder;
• tacrolimus, a medicine used to prevent organ rejection in patients who have had a transplant;
• sertraline, a medicine used to treat depression;
• cyclosporin, an immunosuppressant medicine.

If you are taking Metamizole Kalceks and any of the above medicines, your doctor should monitor your health.
Taking Metamizole Kalceks and methotrexate (an immunosuppressant medicine) at the same time may increase the side effects of methotrexate on blood cell production (hematopoiesis, hematotoxicity), especially in elderly patients. You should avoid taking these medicines at the same time.
You should be cautious when taking this medicine and acetylsalicylic acid used to prevent heart attacks.

Pregnancy and breastfeeding

If you are pregnant or breastfeeding, think you may be pregnant, or plan to have a baby, you should consult your doctor before taking this medicine.
Pregnancy
Available data on the use of metamizole during the first 3 months of pregnancy are limited, but do not indicate a harmful effect on the fetus. In selected cases, if there are no other treatment options, after consulting your doctor or pharmacist, you may take single doses of metamizole in the first and second trimester, provided that the benefits and risks of taking the medicine are carefully weighed. As a rule, administration of metamizole in the first and second trimester is not recommended.
You should not take Metamizole Kalceks during the last 3 months of pregnancy due to the increased risk of complications in the mother and child (bleeding, premature closure of the ductus arteriosus in the unborn child, which normally closes after birth).
Breastfeeding
Metamizole breakdown products pass into breast milk in significant amounts, and the risk to the breastfed infant cannot be excluded. Therefore, you should avoid repeated use of metamizole during breastfeeding.
In the case of single administration of metamizole, you should be advised to discard breast milk for 48 hours after administration.

Driving and using machines

Within the recommended dose range, this medicine does not affect the ability to drive or use machines. If you take higher doses than recommended, especially in combination with alcohol, you should not drive or use machines, as your reaction and concentration abilities may be impaired.

Metamizole Kalceks contains sodium

This medicine contains less than 1 mmol (23 mg) of sodium per daily dose of up to 0.7 ml, i.e., the medicine is considered "sodium-free". If a daily dose of 0.8 ml or more is administered (corresponding to more than 1 mmol of sodium), you should consider: This medicine contains 32.71 mg of sodium (the main component of common salt) per ml of solution. This corresponds to 1.64% of the maximum recommended daily intake of sodium in the diet for adults.

3. How to take Metamizole Kalceks

This medicine should always be taken according to your doctor's or pharmacist's instructions. If you have any doubts, you should consult your doctor or pharmacist.
The dosage and method of administration depend on the desired pain-relieving effect and the patient's health condition.
The dose depends on the severity of the pain or fever and the individual's response to Metamizole Kalceks.
A noticeable effect of the medicine can be expected after 30 minutes of administration. The duration of action is usually about 4 hours.
Metamizole Kalceks is administered as an intravenous or intramuscular injection. In the case of injection, after administration of the medicine, you should remain in a lying position and under the supervision of a doctor to properly monitor your health condition.
If the effect of a single dose is insufficient or if the pain-relieving effect wears off, your doctor may administer another dose, provided that the total amount of medicine taken by the patient in 24 hours does not exceed the maximum daily dose.
Adults and adolescents aged 15 and over
Adults and adolescents aged 15 and over (with a body weight over 53 kg) can be administered 1-2 ml intravenously or intramuscularly as a single dose; if necessary, the single dose can be increased to a maximum of 5 ml (corresponding to 2500 mg of Metamizole Kalceks). The maximum daily dose is 8 ml; if necessary, the daily dose can be increased to a maximum of 10 ml (corresponding to 5000 mg of Metamizole Kalceks).
Infants and children
You should follow the dosage schedule below for single intravenous or intramuscular doses:

Elderly patients and patients in poor general health or with impaired renal function
In elderly patients, weakened patients, and patients with impaired renal function, the dose should be reduced due to the possibility of prolonged elimination of metamizole breakdown products.
Patients with impaired renal or hepatic function
Due to reduced elimination in patients with impaired renal or hepatic function, high doses of metamizole should be avoided. In the case of short-term use, dose reduction is not required. There is a lack of experience with long-term use.

Use in children

Dosage - see the table above.
The usual dose used to treat fever in children is 10 mg per kg of body weight.

Overdose of Metamizole Kalceks

After acute overdose, the following symptoms may occur: nausea, vomiting, abdominal pain, impaired renal function or acute renal failure, nervous system disorders (dizziness, drowsiness, coma, seizures), hypotension, and cardiac arrhythmias. Very high doses may cause harmless red discoloration of the urine.
If you have any further doubts about the use of this medicine, you should consult your doctor, pharmacist, or nurse.

4. Possible side effects

Like all medicines, this medicine can cause side effects, although not everybody gets them.
You should immediatelystop treatment and consult your doctor or go to the hospital if you experience any of the following side effects. These symptoms may indicate agranulocytosis (reduced or complete loss of one type of white blood cell) (rare - less than 1 in 1,000 patients):

• fever (persistent or recurrent)
• chills
• sore throat
• difficulty swallowing
• mouth ulcers or changes in the mucous membranes of the nose, genitals, or anus

Severe skin reactions
You should stop taking metamizole and immediatelyseek medical attention if you experience any of the following severe side effects (frequency not known - cannot be estimated from the available data):

• red, flat patches on the torso, target-like or round, often with blisters in the center, peeling of the skin, mouth ulcers, throat, nose, genitals, and eyes. The occurrence of such severe skin rashes may be preceded by fever and flu-like symptoms (Stevens-Johnson syndrome, toxic epidermal necrolysis);
• widespread rash, high fever, and swollen lymph nodes (DRESS syndrome or hypersensitivity syndrome).

You should stop taking Metamizole Kalceks and immediatelyseek medical attention if you experience any of the following symptoms:

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

You should consult your doctor if you experience any of the following side effects or any problems with the medicine.
Rare(less than 1 in 1,000 patients):

• aplastic anemia (reduced number of red blood cells)
• leukopenia (reduced number of white blood cells)
• pancytopenia (reduced number of all blood cell types)
• thrombocytopenia (reduced number of platelets) (increased tendency to bleed and presence of small red-brown spots (petechiae) on the skin and mucous membranes)
• allergic reactions (anaphylactic or anaphylactoid)
• anaphylactic shock (potentially life-threatening)

Very rare(less than 1 in 10,000 patients):

• reversible renal failure with reduced (oliguria) or almost complete cessation (anuria) of urine output or acute renal failure with proteinuria.

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

• Kounis syndrome (allergic heart attack)
• transient, rarely critical, isolated drop in blood pressure without further symptoms of an allergic reaction. Rapid intravenous injection of the medicine may increase the risk of such a reaction
• interstitial nephritis
• pain at the injection site
• phlebitis
• hepatitis, jaundice, and increased liver enzyme activity in the blood.

Reporting side effects

If you experience any side effects, including those not listed in this leaflet, you should tell your doctor, pharmacist, or nurse. Side effects can be reported directly to the Department of Drug Safety Monitoring of the Office for Registration of Medicinal Products, Medical Devices, and Biocidal Products
Al. Jerozolimskie 181C
02-222 Warsaw
Phone: +48 22 49 21 301
Fax: +48 22 49 21 309
Website: https://smz.ezdrowie.gov.pl
Side effects can also be reported to the marketing authorization holder.
By reporting side effects, you can help provide more information on the safety of this medicine.

5. How to store Metamizole Kalceks

Store in the original packaging to protect from light. Do not freeze.
After opening the ampoule: the medicinal product should be used immediately.
Shelf life after dilution
The chemical and physical stability during use has been demonstrated for 6 hours at 25°C after dilution with 0.9% sodium chloride solution or Ringer's solution.
The chemical and physical stability during use has been demonstrated for 20 minutes at 25°C after dilution with 5% glucose solution.
From a microbiological point of view, if the dilution method does not exclude the risk of microbial contamination, the product should be used immediately. If not used immediately, the user is responsible for the storage time and conditions.
The medicine should be stored out of the sight and reach of children.
Medicines should not be disposed of via wastewater. You should ask your pharmacist how to dispose of medicines that are no longer needed. This will help protect the environment.

6. Contents of the packaging and other information

What Metamizole Kalceks contains

• The active substance of the medicine is metamizole sodium monohydrate

1 ml of solution contains 500 mg of metamizole sodium monohydrate.
1 ampoule (2 ml) contains 1000 mg of metamizole sodium monohydrate.
1 ampoule (5 ml) contains 2500 mg of metamizole sodium monohydrate.

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

What Metamizole Kalceks looks like and contents of the pack

Solution for injection.
Clear, almost colorless to brownish-yellow solution, practically free from particles.
2 or 5 ml of solution in an ampoule made of orange glass
5 ampoules are packaged in a blister pack. 1, 2, or 20 blister packs are placed in a cardboard box.
Pack sizes: 5, 10, or 100 ampoules of 2 ml and 5, 10, or 100 ampoules of 5 ml.
Not all pack sizes may be marketed.

Marketing authorization holder

AS KALCEKS
Krustpils iela 71E
Rīga, LV-1057
Latvia
Phone: +371 67083320
Email: kalceks@kalceks.lv

Manufacturer/Importer

Akciju sabiedrība “Kalceks”
Krustpils iela 71E
Rīga, 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 инжекционен разтвор
Croatia
Metamizolnatrij hidrat Kalceks 500 mg/ml otopina za injekciju
Lithuania
Metamizole sodium Kalceks 500 mg/ml injekcinis tirpalas
Poland
Metamizole Kalceks
Romania
Metamizol Kalceks 500 mg/ml soluție injectabilă
Slovakia
Metamizole Kalceks 500 mg/ml injekčný roztok
Slovenia
Natrijev metamizolat Kalceks 500 mg/ml raztopina za injiciranje
Spain
Metamizol Kalceks 500 mg/ml solución inyectable EFG
Hungary
Metamizole Kalceks 500 mg/ml oldatos injekció
To obtain information on this medicine, you should contact the marketing authorization holder.
Date of last revision of the leaflet:06/2025
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Information intended for healthcare professionals only:

Parenteral administration of the medicine is associated with a high risk of anaphylactic or anaphylactoid reactions.
You should ensure that the injection of the medicine is stopped after the appearance of the first signs of an anaphylactic or anaphylactoid reaction and that the risk of isolated hypotensive reaction is minimized. During parenteral administration, the patient should be in a lying position and under close medical supervision. Furthermore, to prevent the occurrence of a hypotensive reaction, intravenous administration should be performed very slowly, i.e., no more than 1 ml (500 mg of metamizole) per minute.
The solution for injection can be diluted using 5% glucose solution, 0.9% sodium chloride solution, or Ringer's solution. Due to possible pharmaceutical incompatibilities of the metamizole solution, it should not be administered together with other injectable medicines.