"Drugs that are potent intestinal P-gp inducers (e.g., rifampin, St. John’s wort) may alter the concentrations of sofosbuvir."
http://www.gilead.com/~/media/Files/pdfs/medicines/liver-disease/sovaldi/sovaldi_pi.pdf
I'm sure you already know this,alcohol is not a good idea.Beside that grapefruit seems to be a biggy to stay away from when taking an onslot of many different types of medication.