Risk of systemic capillary leak symptoms in patients w/ pre-existing monoclonal gammopathy. Rare cases of pancreatitis often associated w/ hypertriglyceridaemia. Potential risk for transmission of viral diseases. Patients w/ previous or current depressive disorders, particularly those w/ antecedents of suicidal ideation; history of seizures & those receiving treatment w/ anti-epileptics, particularly if epilepsy is not adequately controlled w/ anti-epileptics; severe renal failure; pre-existing cardiac disorders. Regularly perform thyroid function tests, or as clinically indicated, in patients w/ history of thyroid dysfunction. Perform complete blood count & differential WBC counts, platelet counts & blood chemistries, including liver function tests prior to initiation & at regular intervals following introduction of Betaferon therapy, & then periodically thereafter in the absence of clinical symptoms. Asymptomatic elevations of serum transaminases; monitor patients for signs of hepatic injury. Risk of nephrotic syndrome w/ different underlying nephropathies; thrombotic microangiopathy; serious hypersensitivity reactions; inj site necrosis. Potential for immunogenicity. Might influence the ability to drive & use machines in susceptible patients. Pregnancy. Should not be used in childn or adolescents.