Duralast 30 is a medicine used to treat premature ejaculation in adult men. It works by increasing the time it takes to ejaculate and improving control over ejaculation, which can help relieve anxiety or frustration related to fast ejaculation.Duralast 30 is a medicine used to treat premature ejaculation in adult men. It works by increasing the time it takes to ejaculate and improving control over ejaculation, which can help relieve anxiety or frustration related to fast ejaculation.