Analgin

Analgin (sodium metamizole) is a non-opioid analgesic and antipyretic drug widely used to relieve pain and lower body temperature. It belongs to the class of pyrazolone derivatives and also has a weak anti-inflammatory effect. Analgin is widely used in many countries, but its sale is restricted or prohibited in some States because of the risk of serious side effects such as agranulocytosis.

The mechanism of action of Analgin is to inhibit the synthesis of prostaglandins, substances that play an important role in causing inflammation, pain and fever. It blocks the enzyme cyclooxygenase, which is necessary for the production of prostaglandins, thereby reducing pain and fever.

Indications Analgina

1. Anesthesia:

   • Acute and chronic pain syndromes of various origins, e.g. After surgeries, injuries, in diseases of the musculoskeletal system.
   • Colic (renal, biliary).
   • Tumor pain and pain with bone metastases.
   • Menstrual pain.
   • Headache, toothache.

2. Antipyretic:

   • Feverish conditions in colds and infectious diseases, when the use of other antipyretics is ineffective or contraindicated.

Release form

1. Pills

The most common form of analgin is oral tablets. Tablets usually contain:

• 500 mg of active ingredient (metamizole sodium) per unit.

The tablets can be taken with water and are best taken after meals to minimize the risk of stomach irritation.

2. Solution for injection

Analgin is available as a solution for injection that can be given intramuscularly or intravenously. This provides quick relief from severe pain or fever:

• The concentration of the solution is typically 500 mg/mL.

3. Suppositories (rectal suppositories)

For rectal use, analgin is also available in suppository form, which can be a convenient alternative for children or adults who have difficulty taking pills:

• The dosage of suppositories can vary, but they often also contain 500 mg of the active ingredient.

4. Oral solution (drops)

The liquid form of analgin can be used for oral administration in the form of drops, especially convenient for dosing in children:

• Concentration and dosage may vary, instructions for use must be strictly followed.

Pharmacodynamics

1. Mechanism of action: The exact mechanism of action of analgin is not fully understood, but it is thought to bind to central and peripheral receptors to form active metabolites that block cyclooxygenase (COX) and inhibit the formation of prostaglandins, including prostaglandin E2, which reduces the occurrence of pain and inflammation.
2. Analgesicaction: Analgin has a strong analgesic action and can be used to reduce various types of pain, including headache, toothache, muscle pain, as well as in rheumatic and other inflammatory processes.
3. Antipyretic effect: Analgin has antipyretic effect due to its effect on the temperature regulation centers in the hypothalamus of the brain, which helps to reduce body temperature in fever.
4. Anti-inflammatoryeffects: Although analgin is not a typical anti-inflammatory drug, it may help reduce inflammation by blocking the formation of prostaglandins and reducing inflammatory responses.
5. Other actions: Analgin also has antispasmodic effects that help relieve spasms of the smooth muscles of internal organs.

Pharmacokinetics

1. Absorption: After oral administration of metamizole from the gastrointestinal tract it is usually well and rapidly absorbed. Absorption may be slightly delayed when taken concomitantly with food.
2. Distribution: Metamizole is widely distributed throughout the tissues and organs of the body. It penetrates the placental barrier and is excreted in breast milk. Binding to blood plasma proteins is low.
3. Metabolism: Metamizole is metabolized in the liver to form active metabolites, such as 4-methylaminopyridine, as well as inactive metabolites. These metabolites undergo further glucuronidation.
4. Excretion: Metamizole and its metabolites are excreted mainly through the kidneys, both unchanged compounds and in the form of metabolites. About 70-90% of the dose is excreted through the urine in the first 24 hours after administration.
5. Half-life: The half-life of metamizole is about 2-3 hours, although it may be prolonged in elderly patients or in the presence of impaired renal function.

Dosing and administration

Oral administration (Tablets)

• Adults: The usual dose is 500 mg 2-3 times a day. The maximum daily dose should not exceed 3000 mg.
• Children over 10 years of age (or weighing more than 32 kg): The dose is calculated at the rate of 8-16 mg/kg body 3-4 times a day.

Rectal application (Suppositories)

• Adults: Usually use suppositories with a dosage of 500 mg to 1,000 mg 2 to 3 times a day.
• Children: The dose is also calculated by weight, usually not exceeding 10-15 mg/kg body 2-3 times a day.

Parenteral administration (Injections)

• Adults: 500 mg - 1000 mg of metamizole sodium administered intramuscularly or intravenously 2-3 times a day. The maximum daily dose should not exceed 2000-3000 mg.
• Children: 8-16 mg/kg administered intravenously or intramuscularly, no more than 3 times daily.

Features of application

1. Use with caution: Analgin can cause serious side effects including agranulocytosis and shock reactions, especially when administered intravenously.
2. Allergic reactions: Before starting treatment, it is important to make sure that the patient is not allergic to metamizole sodium or other pyrazolone derivatives.
3. Use in pregnancy and lactation: Analgin is not recommended for use during pregnancy and lactation without medical advice.
4. Interaction with other medicines: Metamizole sodium may interact with other medicines, changing their effectiveness or increasing their side effects.

Use Analgina during pregnancy

Using analgin during pregnancy can have negative effects on the fetus and pregnancy. Here are some of the main reasons:

1. Risk of birth defects: Several studies have shown that taking analgin during pregnancy may increase the risk of certain birth defects in the fetus, such as cleft lip and palate.
2. Risk of bleeding: Analgin may increase the risk of bleeding in both mother and baby after birth. This is due to its ability to inhibit platelet aggregation and reduce blood clotting.
3. Toxic effects on fetal kidneys: In some cases, the use of analgin in the last trimester of pregnancy may result in toxic effects on the kidneys in the fetus.

In general, the use of analgin during pregnancy is not recommended without consulting your doctor or obstetrician-gynecologist.

Contraindications

1. Hypersensitivity: People with known hypersensitivity to analgin or other pyrazolones should avoid its use.
2. Asthmatic syndrome: The use of analgin may increase asthmatic symptoms in patients with asthmatic syndrome.
3. Allergic Reactions: Patients with a history of allergic reactions to other drugs, especially nonsteroidal anti-inflammatory drugs (NSAIDs), may be at risk of developing allergic reactions to analgin.
4. Bronchial asthma: The use of analgin may cause bronchospasm in patients with bronchial asthma.
5. Hematologic disorders: Analgin may cause agranulocytosis, thrombocytopenia, and other hematologic disorders; therefore, it is not recommended for patients with blood disorders.
6. Pregnancy and lactation: The use of analgin during pregnancy and lactation may be contraindicated due to potential risks to fetal and infant development.
7. Children: Use of analgin in children may be limited due to the risk of blood reactions and other side effects.
8. Renalinsufficiency: Patients with impaired renal function should avoid using analgin or use it with caution under medical supervision.

Side effects Analgina

1. Allergic reactions: Include hives, itching, rash, swelling, and sometimes anaphylactic shock. These reactions can be particularly dangerous and require immediate medical attention.
2. Bone marrow damage: A rare but serious side effect known as agranulocytosis, which is characterized by a significant decrease in the number of white blood cells in the blood, making the body more vulnerable to infections.
3. Gastrointestinal disorders: Include dyspepsia (digestive disorders), nausea, vomiting, abdominal pain, and diarrhea.
4. Skin reactions: May include itching, redness of the skin, and various types of rashes.
5. Kidney problems: In rare cases, kidney function problems such as increased creatinine and urea levels in the blood may occur.

Overdose

1. Severe poisoning: Analgin overdose can cause severe poisoning, which is manifested by worsening of general condition, drowsiness, decreased blood pressure and respiration.
2. Renal damage: Acute renal damage may develop, especially with prolonged use of high doses.
3. Bone marrow damage: It is possible to develop aplastic anemia or agranulocytosis, conditions in which the bone marrow does not produce enough blood cells.
4. Liver damage: Analgin overdose can also lead to toxic liver damage.

Interactions with other drugs

1. Anticoagulants: Analgin may increase the effect of anticoagulants such as warfarin, which may lead to increased clotting time and increased risk of bleeding.
2. Drugs affecting the digestive tract: Drugs such as antacids or iron-containing preparations may reduce the absorption of analgin from the gastrointestinal tract, which may reduce its effectiveness.
3. Methotrexate: Analgin may increase the toxicity of methotrexate, especially at high doses, by increasing its blood levels and exacerbating its side effects.
4. Cyclosporine: Analgin may increase the toxicity of cyclosporine by increasing its blood levels and increasing the risk of side effects.
5. Probenecid: Probenecid may slow down the elimination of analgin from the body, which may lead to an increase in its level in the blood and prolong the duration of its effect.