Figure 1: Serum alanine aminotransferase levels (ALT) over time. The numbered arrows represent 1. initiation of oral isotretinoin at 30 mg twice a day; 2. increase in the dose to 40 mg twice a day; 3. discontinuation of isotretinoin; 4. initiation of oral cholestyramine powder 4 g a day with breakfast; 5. discontinuation of cholestyramine; 6. reinstitution of oral isotretinoin at 30 mg twice a day; 7. discontinuation of isotretinoin.