healthy patients, 95–99% recover with no long-lasting effects, and antiviral treatment is not warranted. Age and comorbid conditions can result in a more prolonged and severe illness. Certain patients warrant hospitalization, especially those who present with clinical signs of ascites, peripheral edema, and hepatic encephalopathy, and laboratory signs of hypoglycemia, prolonged prothrombin time, low serum albumin, and very high serum bilirubin. In these rare, more severe acute cases, patients have been successfully treated with antiviral therapy similar to that used in cases of chronic hepatitis B, with nucleoside analogues such as entecavir or tenofovir. As there is a dearth of clinical trial data and the drugs used to treat are prone to developing resistance, experts recommend reserving treatment for severe acute cases, not mild to moderate. Chronic Chronic hepatitis B management aims to control viral replication, which is correlated with progression of disease. Seven drugs are approved in the United States: Injectable interferon alpha was the first therapy approved for chronic hepatitis B. It has several side effects, most of which are reversible with removal of therapy, but it has been supplanted by newer treatments for this indication. These include long-acting interferon bound to polyethylene glycol (pegylated interferon) and the oral nucleoside analogues. Pegylated interferon (PEG IFN) is dosed just once a week as a subcutaneous injection and is both more convenient and effective than standard interferon. Although it does not develop resistance as do many of the oral antivirals, it is poorly tolerated and requires close monitoring. PEG IFN is estimated to cost about $18,000 per year in the United States, compared to $2,500–8,700 for the oral medications. Its treatment duration is 48 weeks, unlike oral antivirals which require indefinite treatment for most patients (minimum one year). PEG IFN is not effective in patients with high levels of viral activity and cannot be used in immunosuppressed patients or those with cirrhosis. Lamivudine was the first approved oral nucleoside analogue. While effective and potent, lamivudine has been replaced by newer, more potent treatments in the Western world and is no longer recommended as first-line treatment. It is still used in areas where newer agents either have not been approved or are too costly. Generally, the course of treatment is a minimum of one year with a minimum of six additional months of "consolidation therapy." Based on viral response, longer therapy may be required, and certain patients require indefinite long-term therapy.