Whats the difference in effect of (Generic) Viagra, Levitra and Cialis (Tadalafil) ?
Generic Viagra has a pretty short half-life as far as ED drugs go, so is only really effective taken on demand. Generic Levitra still shows effects after 12+ hours, and Generic Cialis 36+ hours, so some people actually take a daily or every-other-day Levitra or Cialis, respectively, and this can solve the spontaneity problem.