What are the probable symptoms of hepatitis b in a drug user?

Sometimes no symptom. Hep b is a virus which can cause liver disease, including liver failure, but often shows no symptoms for years, even though it is doing damage. Symptoms can be vague: nausea, fatigue, decreased appetite, changes in skin coloring, abdominal pain. Hep b is detected by a blood test, and if you don't carry the virus, you can get a vaccine against it. Hep c is similar, but deadlier & no vaccine yet.