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International generic name
Metamizole sodium
Drug form and composition
Solution for injection. One ampoule of 2 ml contains 1 g Metamizole sodium (0.5
g/ml). One ampoule of 5 ml contains 2.5 g Metamizole sodium (0.5 g/ml). Tablets.
One tablet contains 500 mg Metamizole sodium (100%).
Indications
Analgin tablets are used for the treatment of pains of different origin and variable
intensity: toothache, headache, arthralgia, neuralgia, myositis, mild to moderate
visceral pain, high fever, not responding to other drugs. Analgin injection is used
in cases of acute and severe pain after operations and traumas, pain associated
with neoplastic diseases, colicky pain etc.
Dosage and administration
Ampoules: The ampoules can be administered intramuscularly. The single dose in
all age groups is 8 to 16 mg/kg body weight. The dose should be given according
to the following scheme: 16 to 31 kg body weight - 250 mg Analgin (1/2 ml); 32 to
46 kg body weight - 500 mg Analgin (1 ml); 47 - 62 kg body weight - 500 - 750 mg
Analgin (1 - 1.5 ml); and over 63 kg body weight - 750 - 1000 mg Analgin (1.5 -
2 ml). In cases of persistent pain, the dose can be repeated after 6 to 8 hours.
Maximum daily dose - 4.0 g Analgin. Analgin should not be used parenterally for
a period longer than 3 days. Tablets: The dosage and duration of the treatment must
be determined according to the severity of the pain syndrome. The common dose in
the adults is 250 to 500 mg (1 to 2 tablets) 2 or 3 times daily. The maximum dose
is 3 g/24h. In over 15 year-old children the Analgin dose is 250 mg bid or tid.
Contraindications
Hypersensitivity to metamizole and other pyrazolone derivatives, acute hepatic
porphyria, inborn glucose-6-phosphate dehydrogenase deficiency, severe renal or
hepatic diseases, blood diseases (such as aplastic anemia, leucopenia and agranulocytosis),
pregnancy (the first and the last trimester). Parenteral administration of Analgin
is contraindicated in under 1 year-old children.
Special warnings and precautions
Analgin is used with increased caution in patients with a history for hypersensitivity
to foods and drugs (particularly to analgesic and nonsteroidal antiinflammatory
agents) and also in patients suffering from bronchial asthma, Quincke’s edema, chronic
pulmonary infections. In patients with hypotension and unstable blood pressure,
Analgin should not be used parentarally. If Analgin application is quite necessary,
the blood pressure and the heart rate should be monitored. In cases of prolonged
Analgin treatment, regular blood count checks are necessary (differential count
of the white blood cells). The high Analgin doses can influence unfavourably the
active attention. Because of this in these cases driving and working with machines
are not advised.
Drug interactions
Analgin potentiates the analgesic and antipyretic action of the nonsteroidal
antiinflammatory drugs. The Analgin effects are potentiated by the tricyclic antidepressants,
oral contraceptive agents, allopurinol, alcohol. Analgin decreases the activity
of the coumarin anticoagulants and plasma levels of cyclosporin. The enzyme inductors
(barbiturates, glutethimide, phenylbutazone) attenuate the Analgin effects. Analgin
potentiates the effects of the drugs possessing CNS depressant activity. Concurrent
administration with chlorpromazine is related with a risk of severe hypothermia.
Analgin can be used in combination with buscolysin, atropin, codein.
Adverse reactions
After prolonged administration very rarely can be observed agranulocytosis, leucopenia
and thrombocytopenia, proteinuria, interstitial nephritis. In sensitive patients
rashes, urticaria, Quincke’s edema, asthmatic attacks, and very rarely anaphylactic
shock are possible.
Pharmacological mechanisms
Analgin is a medicine of the pyrazolone group, possessing hard analgesic and
antipyretic effects and moderate antiinflammatory activity. Blocking of the synthesis
of endogenous pyrogens - prostaglandins D and E - is the cause for the antipyretic
activity and also for the analgesic action of this drug. The decrease of the prostaglandis
production in the periphery (and respective decrease of nerve endings sensitivity)
plays a relatively smaller role. In contrast to the other nonnarcotic analgesic
drugs, Analgin stimulates the release of β-endorphins, explaining its activity in
cases of visceral pain. Analgin has a slight spasmolytic activity on the smooth
muscle cells of the biliary and urinary tracts and also on the muscle of the uterus.
Supplied
10 or 100 ampoules of 2 ml (1 g). 10 ampoules of 5 ml (2.5 g). 20 or 500 tablets
of 500 mg.
Expiry
Solution for injection and tablets - 5 years
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