Interferon alphas have been widely used to treat chronic hepatitis C virus infection. These include recombinant interferons, or purified natural leucocyte or Lymphoblastoid interferon. Interferon alpha is usually administered by subcutaneous or intramuscular injection.
Renal excretion is the predominant route of elimination.
Major adverse events can occur, but life-threatening adverse events have been rare in large surveys. These tend to occur within 6-8 hours after starting treatment and are worst with the first injections. These side effects include fever, malaise, tachycardia, chills, headache, arthralgias, and myalgias. Later side effects develop after some days. These include fatigue, malaise, apathy, and cognitive changes.