mrpc sentence1: With Claritin 's decline , Schering-Plough 's best-selling products now are two drugs used together to treat hepatitis C , the antiviral pill ribavirin and an interferon medicine called Peg-Intron . sentence2: With Claritin 's decline , Schering-Plough 's best-selling products are now antiviral drug ribavirin and an interferon medicine called Peg-Intron -- two drugs used together to treat hepatitis C.