metisazone metisazone methisazone (usan) or metisazone (inn) is an antiviral drug that works by inhibiting mrna and protein synthesis, especially in pox viruses. during trials in the 1960s it showed promising results against smallpox infection, but widespread use was considered logistically impractical in the developing countries facing smallpox cases, and it saw only limited use. in developed countries able to cope with the logistic challenge, treatment of smallpox could be achieved just as effectively with immunoglobulin therapy, without the severe nausea associated with metisazone. metisazone names iupac name thiourea other names metisazone identifiers cas number 1910-68-5 y 3d model (jsmol) interactive image chembl chembl1512080 n chemspider 5259074 echa infocard 100.016.016 ec number 217-616-2 kegg d02496 mesh d008720 pubchem cid 6861563 unii k3qml4j07e n comptox dashboard (epa) dtxsid7046413 inchi inchi=1s/c10h10n4os/c1-14-7-5-3-2-4-6(7)8(9(14)15)12-13-10(11)16/h2-5h,1h3,(h3,11,13,16)/b12-8-key: dlgsojooyhwroo-wqlsenkssa-ninchi=1/c10h10n4os/c1-14-7-5-3-2-4-6(7)8(9(14)15)12-13-10(11)16/h2-5h,1h3,(h3,11,13,16)/b12-8-key: dlgsojooyhwroo-wqlsenksbl smiles cn1c(=o)c(=nnc(n)=s)c2ccccc21 properties chemical formula c10h10n4os molar mass 234.28 g/mol pharmacology atc code j05aa01 (who) except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). n verify (what is yn ?) infobox references methisazone has been described as being used in prophylaxis since at least 1965. the condensation of n-methylisatin with thiosemicarbazide leads to methisazone.