Your hep provider is in agreement with Medhelp’s ex resident HCV expert that grapefruit doesn't have interactions with Interferon & Ribavirin,
Douglas Dieterich, MD
Jun 13, 2008
It actually can increase some drug levels because of inhibiting a liver metabolic enyzme. However neither interferon or ribavirin is metabolized by that particular enzyme(p450) so it is OK to drink your grapefruit juice.
http://www.medhelp.org/posts/Hepatitis/Treatment-for-Hep-C--Grapefruit-Juice/show/542498
But there are many other drugs that do have interactions with grapefruit
http://en.wikipedia.org/wiki/Grapefruit%E2%80%93drug_interactions
I avoid grapefruit because it interacts with simvastatin and oxycodone. If you are taking other medications please check with the respective provider and the pharmacist about interaction with grapefruit.