Bactrim-Induced Liver Injury: It Can Happen!

Abstract

Trimethoprim-Sulfamethoxazole (TMP- SMX) is an antibiotic commonly used to treat a variety of infections including urinary tract infections, cellulitis, gastrointestinal infections, and prophylaxis for infections in HIV infected individuals. The most common adverse effects are hypersensitivity reactions and gastrointestinal upset, however hepatotoxicity in immunocompetent patients is rare. This case outlines an immunocompetent male with elevated LFTs two weeks after starting TMP-SMX. 56-year-old Caucasian male with past medical history of hypertension, hyperlipidemia, alcohol abuse, colon cancer post hemicolectomy and hepatic steatosis presented with transaminitis and jaundice. Three weeks prior he was started on TMP-SMX at an urgent care for arm cellulitis. Initially he began to experience fever and fatigue followed by pale colored stools and diarrhea. Outpatient Influenza testing was negative. Laboratory data revealed alkaline phosphatase 750 U/L, aspartate aminotransferase 339 U/L, alanine aminotransferase 857 U/L, total bilirubin of 19.2 mg/dl, international normalized ratio 1.2. Hepatitis A IgM antibody, hepatitis B surface antigen and antibody, hepatitis B IgM core antibody, hepatitis C antibody were non-reactive. Antimitochondrial antibody, cytomegalovirus, human immunodeficiency virus, Epstein Barr virus, anti-smooth muscle antibody, ceruloplasmin level, acetaminophen level and antinuclear antibody were all negative. Liver ultrasound demonstrated patent hepatic vasculature with normal waveforms and hepatic steatosis. Due to the timing of TMP-SMX initiation and onset of symptoms it was concluded that this was probable drug induced liver injury from TMP-SMX use in the setting of hepatic steatosis and chronic alcohol intake. During the hospital stay, liver function tests continued to trend down. Patient was discharged with outpatient follow up. TMP-SMX can cause hepatic injury ranging from transaminitis to liver failure. It can cause injury through hepatocellular injury, hepatocellular and cholestatic injury, or bile duct injury. This can occur within days to months of starting TMP-SMX. Although liver injury is rare with TMP-SMX use in an immunocompetent patient, this case illustrates the importance of a detailed history, physical and early identification of agents causing liver injury.