Molecular model of the drug Tolperisone (C16.H23.N.O). This medication, sold under the brand name mydocalm, is a centrally acting skeletal muscle relaxant used for the treatment of increased muscle tone associated with neurological diseases. Tolperisone has been shown to bind covalently to the SARS-CoV-2 main protease, is antivirally active and has no cytotoxicity. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (blue) and oxygen (red).