How long does it take for itraconazole (sporanox) to start working?

Too soon to tell. Even if it is wildly successful, it takes several months with sporanox (or Lamisil (terbinafine) oral or even laser therapy) to see results. It is because nails grow so slowly and the new nail--the back of the nail--will hopefully be clear, but it takes several months for the new nail to become visible. If working, the nail will grow in like a window shade with progressively more of the nail being clear.