All medical applications known so far involve not pure adamantane, but its derivatives. The first adamantane derivative used as a drug was amantadine – first (1967) as an antiviral drug against various strains of flu[50] and then to treat Parkinson's disease.[51][52] Other drugs among adamantane derivatives include adapalene, adapromine, bromantane, carmantadine, chlodantane, dopamantine, memantine, rimantadine, saxagliptin, tromantadine, and vildagliptin. Polymers of adamantane have been patented as antiviral agents against HIV.[53]