Sildenafil-associated severe cholestatic drug-induced liver injury presenting as persistent jaundice after stone extraction

BACKGROUND: Sildenafil is widely used as a phosphodiesterase type 5 inhibitor for erectile dysfunction. Drug-induced liver injury (DILI) associated with sildenafil is rare, with severe cholestatic cases remaining poorly characterized. A 43-year-old Japanese man was assigned to work in the Philippines two months before presentation and began regularly taking sildenafil (KAMAGRA®) obtained locally. One month before presentation, he developed abdominal pain and vomiting. Magnetic resonance imaging revealed choledocholithiasis, and endoscopic retrograde cholangiopancreatography with stone extraction was successfully performed. However, his severe jaundice persisted and progressively worsened. Upon returning to Japan for further evaluation, imaging studies showed no evidence of persistent biliary obstruction. Liver biopsy demonstrated marked canalicular cholestasis without bile duct destruction, which was inconsistent with prolonged obstructive jaundice. Causality assessment using revised electronic version of Roussel Uclaf Causality Assessment Method for the diagnosis of drug-induced liver injury-Japan, 2023 (RECAM-J 2023) yielded a score of 11 for sildenafil, indicating a highly probable association. After treatment with ursodeoxycholic acid and colestimide, his bilirubin levels gradually normalized. CONCLUSION: Sildenafil formulations obtained outside routine medical supervision may cause severe cholestatic DILI. Careful medication history taking and structured causality assessment are essential for an accurate diagnosis.