**A Critical Risk Factor for a Major Side Effect of Interferon-Alpha Therapy: Activated Indoleamine 2,3- Dioxygenase 1 is Related to Depressive Symptoms Interferon-Alpha Therapy: Activated Indoleamine 2,3-Dioxygenase 1 is Related to Depressive Symptoms**

**A Critical Risk Factor for a Major Side Effect of** 

DOI: 10.5772/intechopen.71013

Yuki Murakami and Yukio Imamura Additional information is available at the end of the chapter

Yuki Murakami and Yukio Imamura

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.71013

### **Abstract**

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bbb.100600

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36 Pharmacokinetics and Adverse Effects of Drugs - Mechanisms and Risks Factors

1042. DOI: 10.1021/jf0011236

Hepatitis C virus (HCV) infection affects approximately 170 million people worldwide. Interferon-alpha (IFN-α) is a cytokine that is related to early viral infection and has both antiviral and antiproliferative properties. The current standard treatment for long-term chronic hepatitis C (CHC) consists of combination therapy with IFN-α and ribavirin, which has a broad spectrum antiviral effect. Despite the potential therapeutic benefits of IFN-α, its administration often causes many side effects, such as somatic and neuropsychiatric symptoms. Depression is a serious and frequently occurring side effect of IFN-α therapy, and this is one of the major reasons for cessation of the therapy. Therefore, in order to avoid the discontinuation of INF-α therapy owing to depressive symptoms, it is important to identify the risk factor(s) leading to the onset of associated depressive symptoms. In this chapter, we introduce our novel findings on the association between IFN treatment and the onset of depression in CHC patients as well as the potential neurobiological mechanisms by which depression may arise. We also highlight a potential approach for predicting the onset risk of depression as a side effect in these patients.

**Keywords:** hepatitis C, IFNs, depression, tryptophan catabolism, indoleamine 2,3-dioxygenase 1
