Examples include Hiprex

http://classyfire.wishartlab.com/tax_nodes/C0000000
http://classyfire.wishartlab.com/tax_nodes/C0000002
http://classyfire.wishartlab.com/tax_nodes/C0002693
http://classyfire.wishartlab.com/tax_nodes/C0002798
http://classyfire.wishartlab.com/tax_nodes/C0002798
http://classyfire.wishartlab.com/tax_nodes/C0004139
http://classyfire.wishartlab.com/tax_nodes/C0000497
http://classyfire.wishartlab.com/tax_nodes/C0004557
http://classyfire.wishartlab.com/tax_nodes/C0004150
https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:6824
http://www.hmdb.ca/metabolites/HMDB0029598
http://www.genome.jp/dbget-bin/www_bget?drug:D00393
https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=4101
https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?sid=310264893
https://www.chemspider.com/Chemical-Structure.3959.html
https://mor.nlm.nih.gov/RxNav/search?searchBy=RXCUI&searchTerm=6832
https://www.ebi.ac.uk/chebi/searchId.do?chebiId=6824
https://www.ebi.ac.uk/chembldb/index.php/compound/inspect/CHEMBL1201270
https://zinc.docking.org/substances/ZINC000086040406
http://www.rxlist.com/hiprex-drug.htm
https://www.drugs.com/mtm/methenamine.html
http://www.pdr.net/pdr-consumer-monograph/hiprex?druglabelid=1906&ConsumerId=5750
https://en.wikipedia.org/wiki/Hexamethylenetetramine