Key takeaways
Adefovir (Hepsera) and peginterferon alfa-2a (Pegasys) are both used to treat hepatitis B, but they belong to different medication classes. Adefovir is a nucleoside reverse transcriptase inhibitor (NRTI) taken orally once a day, while Pegasys is an interferon alpha injected under the skin once a week. Adefovir is available as a generic, making it a lower-cost option, but it is not a first-choice treatment due to the risk of viral resistance. Pegasys is not recommended for hepatitis C treatment anymore and is only available as a brand name prefilled syringe for easier use. Common side effects of adefovir include weakness and headache, whereas Pegasys can cause flu-like symptoms, such as tiredness and fever. Pegasys also has more serious potential side effects, including mental health issues and autoimmune disorders. Both medications require regular monitoring, but Pegasys has more complex administration and storage requirements.
