Management and Treatment of Injection Drug Users with Hepatitis C Virus (HCV) Infection and HCV/Human Immunodeficiency Virus Coinfection

Abstract

Injection drug use is the major mode of hepatitis C virus (HCV) transmission in developed countries. Despite this, relatively few current and recovering injection drug users (IDUs) have received HCV treatment. Studies among individuals with a recent history of injection drug use or those receiving drug dependency treatment have provided evidence that these groups can be successfully treated for chronic HCV infection. These studies have provided the impetus to change guidelines for treatment of current and recovering IDUs, with a move toward individualized HCV treatment assessment and the removal of defined periods of illicit drug use abstinence. Strategies to improve access to HCV treatment for current and recovering IDUs include drug dependency treatment education and training for hepatologists and other HCV treatment physicians, HCV treatment education and training for addiction medicine physicians, development of multidisciplinary clinics, and peer-based eduction and support for individuals considering and receiving HCV treatment.

High rates of sustained virological response in hepatitis C virus-infected injection drug users receiving directly observed therapy with peginterferon alpha-2a (40KD) (PEGASYS) and once-daily ribavirin

“…Although there is an increased risk of infection in patients with longer durations of injection drug use (Amon et al, 2008), there is a particularly high risk of infection in the early stages of use (Hagan et al, 2007). Untreated, chronic HCV infection (CHC) leads to cirrhosis in around 10% of infected patients after around 20 years and in around 30% after 40 years, which is particularly relevant in the IDU population as the majority become infected with HCV at a relatively young age (b40 years; Dore & Thomas, 2005). Despite the fact that IDUs represent around 60% of new cases of HCV infection, there has been a tendency to exclude such individuals from treatment due to concerns regarding adherence, possible reinfection, and potential toxicity of HCV treatment, particularly with regard to the neuropsychiatric effects of interferon (IFN)-based therapy.…”

Hepatitis C virus reinfection in injection drug users

“…5 Pharmacologic advances have led to the development of effective treatment regimens leading to a virological "cure" in 50% of HCV-infected subjects receiving pegylated interferon in combination with ribavirin. 6,7 Although these outcomes have been replicated in active IDUs, 8,9 there is still concern that the risk of HCV reinfection through recurrent parenteral exposure will negate the benefits of treatment.In fact, reinfection with HCV after spontaneous clearance has been demonstrated to occur in IDUs with ongoing risk behavior, 10,11 as well as in other groups, including polytransfused children with thalassemia 12 and subjects undergoing liver transplantation. 13 Reinfection does occur in chimpanzees rechallenged with HCV after clearance of the original infection, 14-17 but the resistance to subsequent HCV infection is relatively greater, which is likely related to immune protection.…”

“…5 Pharmacologic advances have led to the development of effective treatment regimens leading to a virological "cure" in 50% of HCV-infected subjects receiving pegylated interferon in combination with ribavirin. 6,7 Although these outcomes have been replicated in active IDUs, 8,9 there is still concern that the risk of HCV reinfection through recurrent parenteral exposure will negate the benefits of treatment.…”

Underlying Pathophysiology of HCV Infection in HIV-Positive Drug Users

“…11 An estimated incidence of HCV among injection drug users is 30-90%. 12 HCV is dominant among drug users who share drug-using equipment, practice front-loading and/or frequently inject cocaine, heroin, opium and poly-drugs. 13,14 Liver, the major in vivo detoxification site for drugs, is strained due to alcohol and drug abuse in addition to HCV infection.…”