Bulevirtide, sold under the brand name Hepcludex, is an antiviral medication for the treatment of chronic hepatitis D (in the presence of hepatitis B). The most common side effects include raised levels of bile salts in the blood and reactions at the site of injection. Bulevirtide works by attaching to and blocking a receptor (target) through which the hepatitis delta and hepatitis B viruses enter liver cells. By blocking the entry of the virus into the cells, it limits the ability of HDV to replicate and its effects in the body, reducing symptoms of the disease.