Reactive Metamizole Metabolites Enhance the Toxicity of Hemin on the ATP Pool in HL60 Cells by Inhibition of Glycolysis

Abstract

Metamizole is an analgesic, whose pharmacological and toxicological properties are attributed to N-methyl-aminoantipyrine (MAA), its major metabolite. In the presence of heme iron, MAA forms reactive metabolites, which are toxic for granulocyte precursors. Since decreased cellular ATP is characteristic for MAA-associated toxicity, we studied the effect of MAA with and without hemin on energy metabolism of HL60 cells, a granulocyte precursor cell line. The combination MAA/hemin depleted the cellular ATP stronger than hemin alone, whereas MAA alone was not toxic. This decrease in cellular ATP was observed before plasma membrane integrity impairment. MAA/hemin and hemin did not affect the proton leak but increased the maximal oxygen consumption by HL60 cells. This effect was reversed by addition of the radical scavenger N-acetylcysteine. The mitochondrial copy number was not affected by MAA/hemin or hemin. Hemin increased mitochondrial superoxide generation, which was not accentuated by MAA. MAA decreased cellular ROS accumulation in the presence of hemin. In cells cultured in galactose (favoring mitochondrial ATP generation), MAA/hemin had less effect on the cellular ATP and plasma membrane integrity than in glucose. MAA/hemin impaired glycolysis more than hemin or MAA alone, and N-acetylcysteine blunted this effect of MAA/hemin. MAA/hemin decreased protein expression of pyruvate kinase more than hemin or MAA alone. In conclusion, cellular ATP depletion appears to be an important mechanism of MAA/hemin toxicity on HL60 cells. MAA itself is not toxic on HL60 cells up to 100 µM but boosts the inhibitory effect of hemin on glycolysis through the formation of reactive metabolites.

Case Report: Simultaneously Induced Neutropenia and Hemolysis After a Single Metamizole Dose

“…In part, 4-methylaminoantipyrine is bound to plasma proteins. Metamizole and its metabolites may act as hapten on the surface of blood cells and lead to cell lysis after the binding of antibodies [19][20][21][22]. Further, in the presence of heme, a weak antioxidative defense, impairment of enzymes, or other highly oxidative compounds, 4-methylaminoantipyrine cytotoxicity is increased and facilitates the development of neutropenia.…”

Parenteral Ready-to-Use Fixed-Dose Combinations Including NSAIDs with Paracetamol or Metamizole for Multimodal Analgesia—Approved Products and Challenges

“…Like paracetamol, metamizole is a common analgesic and antipyretic drug but with low anti-inflammatory activity. It is generally well tolerated and can treat several painful conditions including post-operative pain, headaches, migraines, neuropathic pain, cholic pain, and cancer pain [ 44 , 45 , 46 , 47 , 48 ]. For post-surgery purposes, metamizole is a more effective analgesic than paracetamol and at least as effective as NSAIDs [ 47 ].…”

“…As monotherapy and due to its presumably favorable safety profile, metamizole is preferred over NSAIDs [ 44 ]. However, metamizole has been related to cases of severe neutropenia and agranulocytosis (myelotoxicity) and, due to this fact, it was banned from the market in some countries such as the US, the UK, Sweden, Canada, Australia, Norway, and India [ 46 , 47 , 48 , 49 , 50 , 51 , 52 ]. Nevertheless, metamizole is still available in some European and South American countries [ 44 , 47 , 48 , 49 ].…”

“…However, metamizole has been related to cases of severe neutropenia and agranulocytosis (myelotoxicity) and, due to this fact, it was banned from the market in some countries such as the US, the UK, Sweden, Canada, Australia, Norway, and India [ 46 , 47 , 48 , 49 , 50 , 51 , 52 ]. Nevertheless, metamizole is still available in some European and South American countries [ 44 , 47 , 48 , 49 ]. Indeed, the incidence of metamizole-induced myelotoxicity is controversial and varies widely between studies.…”

“…The mechanisms of action are not completely understood; however, in the literature, metamizole is presented as a prodrug, while its metabolites act at both peripheral and central levels [ 44 , 47 , 48 ]. 4- N -methyl-aminoantipyrine (4-MAA) is the main metabolite in plasma [ 47 , 55 , 56 ].…”