« Back to Farmacia Journal 1/2014

EXPERIMENTAL RESEARCH ON POSSIBLE INTERACTIONS OF HIGH DOSES OF METAMIZOLE SODIUM WITH THE ENDOGENOUS CANNABINOID OR DOPAMINERGIC SYSTEMS

LAURENŢIU COMAN¹, HORIA PĂUNESCU^*1, OANA ANDREIA COMAN¹, LUMINIŢA CRISTINA CHIUŢU², ION FULGA¹

Download Full Article PDF

For metamizole sodium the four specific effects of cannabinoids in mice were previously noticed by us (the tetrad): analgesia, sedation, hypothermia, catalepsy. For verifying the cannabinoid hypothesis, the effects of the association between metamizole sodium 1g/kg bw and a CB1 receptors antagonist (AM281) in the hot-plate test and on body temperature were tested in mice. The results showed that metamizole in high doses possessed a central analgesic and hypothermic effect, but they were not influenced by the CB1 receptors antagonist. These findings suggested that the demonstrated analgesic and hypothermic effects of metamizole do not involve a cannabinoid mechanism. Another hypothesis regarding the dopaminergic action of metamizole was analysed. Catalepsy was tested in mice treated with metamizole or chlorpromazine alone or associated with bromocriptine. The results showed that the cataleptic effects of metamizole are not due to the blockage of the dopaminergic receptors. Regarding the cannabinoid-like effects of metamizole (the tetrad), further research of other mechanisms of action of metamizole is required. A hypothesis for the hypothermic effect of metamizole could be its implication in stimulation of the thermolysis process. This effect for metamizole was not demonstrated until now and it may extend its indications area in inducing controlled hypothermia in humans.