How does interferon work in hepatitis c

The more common long-term side effects of interferons are typically less severe. These side effects can include:. They can assess you and determine if the interferons or something else is causing your symptoms. Side effects highlighted in the boxed warning include autoimmune diseases, mood disorders, increased infections, and stroke.

Antibodies are cells that fight harmful substances in your body. Antibodies may mistake some of your healthy cells for invaders and attack them. This can cause a range of autoimmune disorders , such as psoriasis , rheumatoid arthritis , and lupus. Interferons can cause or worsen serious depression or other mental illness. Call your doctor right away if you have serious mood changes, depression, or thoughts of suicide.

White blood cells fight infections as part of your immune system. Interferons can change the way white blood cells fight infection. Interferons can also slow cell growth, which can cause lower levels of white blood cells. Low levels of white blood cells can cause more frequent infections. And if you already have infections, interferons can make them more serious. You may also experience worsened symptoms — like pain and itching — of old infections such as herpes or fungal infections.

Call your doctor if any of these symptoms appear suddenly or get worse. Levels of white blood cells typically return to normal when interferon therapy is stopped, alleviating the increased risk of infection. Interferons can cause increased blood pressure and heart rate, which are both risk factors for stroke.

These actions can cause two types of stroke : ischemic and hemorrhagic. An ischemic stroke occurs when a blood clot reduces the blood supply to the brain. Hemorrhagic strokes occur when a blood vessel in the brain leaks or bursts and damages brain tissues. Symptoms of a stroke can include:. They can prepare to help you if you have stroke symptoms and cannot help yourself. Interferons used to treat hepatitis C could have other serious side effects in addition to the boxed warning effects.

These can include decreased blood cell counts. With decreased blood cell counts, you have low levels of white blood cells, red blood cells, and platelets in your body. Typically, this effect reverses once interferon therapy is stopped. Decreased blood cell counts occur because interferons can prevent your bone marrow the tissue inside your bones from working well. Your bone marrow produces your blood cells. In addition to increased infections see above , decreased blood cell counts can cause the following serious effects:.

The three types of interferon are referred to by Greek letters - alpha, beta and gamma. In its naturally occurring form alpha interferon is produced by the body to fight infections, notably flu.

It is responsible for many of the symptoms associated with flu, such as headaches, fever, and the shivers. As a treatment for hepatitis C, interferon is synthetically produced in a laboratory and administered by injection under the skin in very high doses. It is hardly surprising that some of the usual side effects of taking interferon are actually flu-like symptoms. Laboratory-produced standard interferon is broken down relatively fast by the body.

As a result, its effectiveness decreases. This allows the hepatitis C virus to multiply between each injection. Pegylation is a process whereby a large molecule chain is attached to the interferon to slow the rate at which it is broken down. This molecule chain allows consistent levels of the drug to circulate in the body.

Consequently it can maintain a consistent attack on the virus. It also means that while standard interferon needs to be taken 3 times a week, pegylated interferon only has to be injected once a week.

Two drug companies manufacture pegylated interferon. They are similar, although not identical. Click on the links for more information.

The previous viral load to treatment was analyzed in records, averaging 1. The duration of antiviral treatment was 48 weeks in The duration of other treatment courses varied: in These data were missing for 2.

Figure 1. Frequency of side effects associated with dmg therapy for Hepatitis C in patients treated at University Hospital of Sergipe in Northeast Brazil from RBV dosage was modified in RBV treatment was interrupted temporarily in Of the IFN dose interruptions, Treatment was stopped completely in In a number of cases the reasons for treatment discontinuation were reported, these included lack of response to medication, adverse events, and non-compliance.

Overall, The average number of adverse events was 6. The most common adverse event was asthenia 8. Adverse events were reported in cases with a total of events, these are summarized in Figure 1. Neutropenia was observed during treatment in Filgrastim was administered in In Anemia was observed in Some medications were administered to reduce the effects of adverse reactions in patients receiving antiviral therapy. Overall, 93 different drugs were administered, with an average of 1.

The most frequently administered were: paracetamol In cases the clinical outcome was inconclusive. In the cases in which clinical outcome could be evaluated, Of the patients who were ETR, The main for patients not achieving ETR were: suspension of treatment due to adverse events The SVR rate was Among the patients achieving SVR, The proportion of patients achieving SVR was higher for those on-cirrhotic Table 3 and Figure 2 summarize results according to the degree of fibrosis, Hepatitis C virus genotype, and medication received.

IFN-based treatment was associated with improved survival and reduced the risk of hepatocellular cancer. In one clinical study, low doses of peginterferon and ribavirin were as effective as higher dose levels [ 24 , 36 ]. Current treatments for chronic HCV infections have several limitations, as they result in rates of sustained virus responses that were lower in black and Latino patients than in non-Latino whites [ 37 , 38 ]. Long-term, IFN-based treatment did not halt the progression of chronic HCV infections in patients not responding to initial treatment [ 36 ].

A variable percentage of patients treated with IFN develop anti-IFN antibodies, but surprisingly, there appears to be little correlation between the presence of such antibodies and the response to IFN [ 39 ]. IFN- is also useful in the treatment of cryoglobulinemia and focal glomerulopathy, complications of chronic HCV infections [ 40 ].

Unfortunately, the prolonged peginterferon therapy necessary to control chronic HCV or HBV infections was often associated with serious side effects such as fatigue, fever, and myalgias, symptoms of many acute virus infections, possibly because such effects are due to the induction of IFNs by the infecting agents. Usually these symptoms respond to treatment with nonsteroidal anti-inflammatory agents [ 27 ].

In some patients, treatment with IFNs has also resulted in psychiatric problems such as depression, anxiety, and excessive irritability that may require treatment with psychoactive pharmaceuticals.

More severe toxicities, such as cytopenias and autoimmune disorders, also have rarely been reported in patients treated with IFNs [ 41 ]. Combinations of additional new agents with the currently employed therapies may provide effective treatment for a much larger percentage of HCV patients than are currently responding to anti-HCV treatment [ 31 ].

Friedman and Sara Contente. This is an open access article distributed under the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Article of the Year Award: Outstanding research contributions of , as selected by our Chief Editors. Read the winning articles. Special Issues. Academic Editor: Ming-Lung Yu. Received 13 Apr Revised 02 Jul Accepted 30 Jul Published 06 Sep Abstract Interferons were first described in , but it was not until 34 years after their discovery that sufficient quantities of it were available for treatment of hepatitis C virus HCV infections, Clinicians now have an excellent understanding of the basis for the effectiveness of interferon alpha IFN- in the therapy of this disease.

References A. Isaacs and J. View at: Google Scholar D. Jones, J. Galbraith, and M. View at: Google Scholar J. View at: Google Scholar K. Cantell, S. Hirvonen, and V. Pestka, Ed. View at: Google Scholar T. Merigan, S. Reed, T. Hall, and D.

View at: Google Scholar R. Sundmacher, D. Neumann Haefelin, and K. View at: Google Scholar A. Arvin, S. Feldman, and T. Friedman and J. View at: Google Scholar H.