Combination vardenifil and tadalifil drug induced liver injury; case report and review of the literature of liver injury associated with phosphodiesterase type 5 inhibitors.

Background: Phosphodiesterase type 5 inhibitors (PDE5I) are prescribed for erectile dysfunction and pulmonary hypertension. Despite its widespread use, there are only seven cases of drug-induced liver injury (DILI) associated with PDE5I, none associated with vardenafil or avanafil. We report a patient who had taken vardenafil and tadalafil individually for several years without developing symptoms of liver injury. However, after taking vardenafil and tadalafil together on 2 consecutive days, he developed severe cholestasis. Methods: Causality was determined using Roussel Uclaf causality assessment method (RUCAM). Results: The patient is a 72-year-old White man in excellent health who drank 2 units of alcohol, three times/week. Previously, he had used vardenafil for more than 2 years and tadalafil for 3 months as single agent for erectile dysfunction without any complications. He took vardenafil and tadalafil for 2 consecutive days and 5 days later, he developed dyspepsia, loss of appetite, jaundice, and intense itching. Liver tests showed mixed cholestatic/hepatocellular pattern of injury. Histology showed marked cholestasis with minimal inflammation. He remained cholestatic for 5 weeks before a full recovery 2 months later. The patient then resumed vardenafil monotherapy with no recurrent liver dysfunction. RUCAM causality score 7 indicates that the combination of PDE5I is probable cause of liver injury. The similarities among the eight cases of PDE5I DILI include a relatively short latency, cholestatic histological features, and complete recovery. Biochemical pattern of liver injury is variable. Conclusions: PDE5I DILI is a rare event that can result in severe acute liver injury.