Used primarily in the treatment of chronic hepatitis B virus (HBV) infection, clevudine acts as a nucleoside analog that inhibits viral replication by targeting the HBV polymerase. It has demonstrated potent and prolonged antiviral activity, with studies showing significant reduction in viral load during treatment. Due to its long half-life, it allows for once-daily dosing, improving patient compliance. However, concerns over mitochondrial toxicity and potential for viral resistance have limited its long-term use. It has been approved and used clinically in some Asian countries but is not widely available globally. Research also explored its activity against other viruses, though with limited success compared to its effect on HBV.