You may already know most of the names: http://www.vulcangas.com/wpvlcg/wp-content/plugins/cmb2/languages/it/generico-cialis-nome.html, Levitra, Staxyn, Stendra, Viagra. However, there are subtle differences in how long they stay effective and how quickly they begin to work. Levitra takes about 30 minutes to start working and the effects last a little longer than Viagra, about 5 hours.