case_images: PMC6662412_01
case_images: 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.
case_images: CRIHEP2019-9270827.001.jpg
case_images: PMC6662412_01_CRIHEP2019-9270827.001.jpg
case_images: fig1
case_images: Baseline blood tests were all within normal limits prior to starting isotretinoin, 30 mg twice a day (1.0 mg/kg) (Figure 1, arrow 1). The significance of an elevated ALT to 62 U/L [nl: <30 U/L] was uncertain (Figure 1, arrow 2). Isotretinoin was discontinued (Figure 1, arrow 3). C, as well as antinuclear antibodies, was negative. Considering enterohepatic recycling of potential hepatotoxic isotretinoin metabolites, the patient was started on cholestyramine powder, 4g daily with breakfast (Figure 1, arrow 4). This was discontinued after 7 weeks as ALT levels were returning towards normal (Figure 1, arrow 5). The ALT levels completely returned to normal values one month later and returned to baseline 2 months thereafter (Figure 1). Because of worsening cystic acne unresponsive to topical retinoids, topical antibiotics, and oral doxycycline, another course of isotretinoin was started approximately 3 years later (Figure 1, arrow 6). ALT and other liver function tests remained normal (Figure 1, arrow 7). All inflammatory and cystic acne resolved by the conclusion of treatment.