Description
Metamalgin Pharmacodynamics
Sodium metamizole is a derivative of pyrazolone, non-selectively inhibits cyclooxygenase and reduces the formation of prostaglandins from arachidonic acid.
It has analgesic, antipyretic and some antispasmodic (against smooth muscles and biliary tract) effects. The action develops in 20-40 minutes and reaches a maximum in 2 hours.
When administered intravenously, the maximum effect develops in 20-40 min.
Indications
– Severe acute or chronic pain syndrome in trauma and post-operative pain syndrome, colic, cancer and other conditions where other therapeutic measures are contraindicated.
– Fever resistant to other therapies.
Contraindications
– Hypersensitivity to sodium metamizole and other pyrazolone derivatives, as well as to pyrazolidines such as phenylbutazone (including patients who have undergone agranulocytosis due to the use of these drugs), or other components of the drug;
– Analgesic bronchial asthma or analgesic intolerance (urticaria-angioedema type), i.e., patients with bronchospasm or other forms of anaphylactoid reactions (e.g., urticaria, rhinitis, angioedema) in response to use of salicylates, paracetamol or non-steroidal anti-inflammatory drugs such as diclofenac, ibuprofen, indomethacin or naproxen
– Impaired medullary hematopoiesis (e.g., after cytostatic therapy) or diseases of the hematopoietic organs;
– hereditary deficiency of glucose-6-phosphate dehydrogenase (hemolysis);
– acute intermittent hepatic porphyria (risk of porphyria attacks);
– acute renal or hepatic failure;
– Pregnancy (first and third trimesters) and breastfeeding;
– Infants (under 3 months of age or weighing less than 5 kg);
– infants aged 3 to 12 months (contraindication for intravenous administration only).
Dosage and administration method
- Intravenously, intramuscularly.
Parenteral administration of the drug is indicated only when oral administration is impossible. - It is recommended to warm the drug to body temperature before its administration.
- Adults and adolescents 15 years of age and older: 1-2 ml (500 mg/ml) of sodium metamizole solution (intramuscularly or intravenously) is recommended as a single dose.
- Maximum daily dose is 2000 mg divided into 2-3 doses per day. The maximum single dose is 1000 mg.
- Children aged 3-12 months (body weight 5-9 kg) are administered only intramuscularly in dose 50-100 mg per 10 kg body weight (0.1-0.2 ml of 500 mg/ml solution). A single dose may be administered up to 2-3 times a day.
- Intravenous infusion should be carried out very slowly (infusion rate not exceeding 1 ml/min) in the prone position of the patient, under control of blood pressure, pulse and respiratory rate to minimize the risk of blood pressure drop. At the first sign of anaphylactic/anaphylactoid reactions, discontinue the drug.
- Since there is concern that the drop in blood pressure of non-allergic genesis is dose-dependent, the amount of sodium metamizole solution more than 2 ml (1000 mg) should be administered with extreme caution.
- A critical drop in blood pressure and shock may occur if the drug is administered too rapidly.
- Elderly patients should use smaller doses due to possible decrease in excretion of sodium metabolites from the body.
- Patients in severe condition and with impaired creatipine clearance should use smaller doses due to decreased excretion rate of sodium metabolites of sodium metamizole.
- In patients with impaired liver and renal function the drug excretion rate is slower, therefore repeated use of the drug should be avoided, there is no experience of long-term use. No dosage adjustment is required for short-term therapy.
- Duration of treatment
When used as analgesic agent the duration of treatment is 1-5 days. When used as antipyretic drug – 1-3 days.
