© 2007 by The Brazilian Journal of Infectious Diseases and Contexto

The treatment of hepatitis C involves combining conventional interferon (IFN) or pegylated IFN (PEG-IFN) with ribavirin (RBV). These therapeutic regimens are associated with numerous adverse events, among which constitutional and neuropsychiatric symptoms, as well as hematological abnormalities, stand out [1,2]. The adverse events observed with the use of PEG-IFN or conventional IFN are similar, and the frequencies of those events are shown in Table 1 [3-5]. Adverse events resulting from the treatment of hepatitis C can jeopardize the quality of life of patients and their response to treatment. The control of those events involves medicinal and non-medicinal interventions. The latter include a reduction in the dosage of IFN or RBV and discontinuation of the treatment. A temporary or permanent reduction in the dosage of PEG-IFN, conventional IFN or RBV as a result of an adverse event is necessary in approximately 30 % of patients. In 10 % of patients it is necessary to discontinue the treatment [4]. Hematological abnormalities (neutropenia, anemia and thrombocytopenia) and depression are the most common causes of dose reduction. The maintenance of the dosages of medications used in the treatment of hepatitis C and of the recommended course of treatment are important for the effectiveness of the therapy, as shown in Figure 1 [6]. Dose reduction is associated with lowering the rate at which a sustained viral response (SVR) is achieved. Early identification and strategies for controlling adverse events are important in the prevention of moderate and severe complications. These practices also attenuate the deleterious effects on the quality of life of patients and maximize the effectiveness of treatment for hepatitis C. Constitutional Symptoms Constitutional symptoms such as fatigue, headache and myalgia are the most common adverse events in patients Table 1. Adverse events associated with using the pegylated interferon-ribavirin combination in the treatment of hepatitis