Pharmacotherapy for Hepatitis C Virus Infection: Human Immunodeficiency
Hepatitis C Virus/Human Immunodeficiency Virus Co-infection
The coexistence of HCV and HIV poses a larger problem for the management of HCV. Because the modes of HIV and HCV transmission are similar, approximately 15% to 30% of HIV patients also become infected with HCV. Patients who have not used protease inhibitors (PIs) and those who consume excessive alcohol or who have low CD4 T-cell counts progress more rapidly to cirrhosis than patients without HCV. For patients with both HCV and HIV infections, concerns arise about drug-drug interactions between therapies used for each disease and drug-disease interactions, such as the increased incidence of hepatotoxicity from antiretroviral therapy combined with underlying hepatic dysfunction resulting from HCV.
The effect of HCV co-infection on the natural history of HIV is controversial. Studies have shown that HCV seropositivity can increase the progression to a new AIDS-defining illness or death. Other studies have concluded that in assessing the effect of HCV co-infection on clinical and immunological progression of HIV-1 disease and the response to highly active antiretroviral therapy (HAART), HCV-infected patients are the least likely to receive HAART. In addition, no differences were found in the risk of an AIDS-defining illness among HCV-infected patients, compared with patients not infected with HCV, even when various CD4 cell count ranges were compared between the groups.
Selecting the appropriate regimen for treating HIV alone is a challenge in and of itself, but pharmacotherapeutic management is even more challenging when HIV infection is coupled with HCV infection. Drug-drug interactions that occur with HCV/HIV therapies can cause an increased incidence of side effects, although this increase can be offset if the drugs selected in the HIV regimens are associated with lower hepatotoxicity and if patients are educated about disease progression and how to overcome it.
Drugs in Development
Future therapies for the management of HCV infection are under development, and at least 15 agents are in the pipeline. Antiviral agents that directly attack enzymes used by the virus to replicate itself are needed to slow disease progression. Researchers are currently studying the use of protease, heli-case, and polymerase inhibitors, but limited data have been reported. DNA vaccines, which would stimulate T-cell activity, and antisense agents, which would work by binding to inter-feron-resistance sites, are also potential tools for preventing and managing the illness. Therapy within the next five years will probably take the form of multidrug combinations and will, ideally, offer a more tolerable side-effect profile, achieve a better compliance rate among patients, and reduce serum HCV RNA levels.
canadian pharmacy online
Educating patients about adherence to medication is an important factor in controlling HCV infection and should be emphasized at every patient visit when therapy is initiated (Table 3). With HIV treatment, antiretroviral medication adherence at a rate below 95% can prevent complete virologi-cal suppression; the same holds true for anti-HCV therapy. Adherence at week 12 is associated with a high probability of achieving SVRs. HCV infection can be controlled with early detection, proper therapy, and patient education.
Chronic HCV infection is a major public health concern, affecting primarily African-American men in the fourth and fifth Table 3 Tips on Hepatitis C Virus (HCV)
Infection for Patients and Providers
Table 3 Tips on Hepatitis C Virus (HCV) Infection for Patients and Providers
Counsel patients on the risks of HCV infection as follows:
• The natural history of the illness is slowly progressive (the median time to cirrhosis is 28 to 32 years).
• HCV-positive patients should not donate blood, organs, tissues, or semen.
• Because the risk of sexual transmission is small, barrier protection (e.g., condoms) is not recommended; however, barrier methods can decrease the risk of transmission of HCV and other sexually transmitted diseases as well.
• Although transmission of the virus from mother to child is rare, transmission rates are higher in HIV-positive mothers.
• Breast-feeding is not contraindicated for HCV-positive patients.
• Household members should avoid third-party contact with blood by not sharing toothbrushes, razors, and needles, and they should cover open wounds.
• The use of standard precautions to prevent transmisson to health care providers and patients is essential in all health care facilities.
• Needle-and-syringe exchange programs may help reduce parenterally transmitted HCV infection as well as other infections, such as HIV.
• Scheduled classes on medication use and adverse effects and their management can help enhance patients’ understanding of HCV infection.
Because the virus can lie dormant for decades before signs or symptoms occur, practitioners are faced with the challenge of trying to prevent and control its spread. Because this is a blood-borne disease, health care workers and high-risk groups such as IV drug users and HIV-positive patients, should be informed about the risks and should undergo testing. Using the EIA to detect HCV and following up with PCR is the current standard for the initial diagnosis.
Newer agents are being developed, but until they are approved, we do not have enough effective treatment options, especially for patients with genotype 1b.