| Interferon Thrapy |
| What Is Interferon? |
| Interferon is a natural substance produced by your body in response to viral infection. The substance helps the body distinguish between infected and non-infected cells, targeting infected cells for destruction. Interferon is often responsible for the achy sore muscles and joint pain that we get with the flu. In viral hepatitis, the virus is often invisible to the immune system and therefore persists and causes the infection to become chronic. Interferon increases the immune systems ability to detect or see the infection. Think of it like eye glasses for your immune system. Interferon also helps by directly suppressing viral replication within the liver. |
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| Who Should Receive Interferon? |
Chronic viral hepatitis is an inflammation of the liver caused by a persistent viral infection in the body. The different types of hepatitis have been given letter names such as A, B, C, etc. Certain patients with Chronic Hepatitis B or Chronic Hepatitis C are candidates for Interferon therapy. Your doctor can best decide if this therapy is needed or likely to help. However, some generalizations are possible.
Less than 50% of Chronic Hepatitis B carriers are eligible for therapy. The infection must be present for greater than six months. Certain blood tests called liver enzymes (ALT and AST) serve as indicators of liver inflammation These enzyme levels should be elevated greater than 1.5 times normal since patients with normal liver enzymes, so called "healthy carriers," rarely if ever respond to Interferon. Lastly, evidence of active viral replication should be present. Active viral replication can be assessed with special blood tests which detect the viral antigen (HBeAg) or viral DNA. If you have Chronic Hepatitis B and you meet these three criteria, you may be eligible for Interferon.
Many more Chronic Hepatitis C patients are candidates for Interferon treatment. If there is evidence of chronic infection, increased liver enzymes, and the absence of cirrhosis on liver biopsy, you may be eligible. |
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| Who Should Not Receive Interferon? |
| Contraindications to Interferon include ongoing abuse of alcohol or drugs, pregnancy, low blood count anemia, advanced or decompensated cirrhosis, major depression or a past history of major depression, or an autoimmune disease such as Lupus. |
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| How Is Interferon Administered? |
| Interferon unfortunately must be given as an injection similar to insulin in diabetics. Though the dose varies, patients with Chronic Hepatitis C usually receive 3 million units 3 times per week. Individuals with Chronic Hepatitis B receive a higher dose of 10 million units 3 times per week. The duration of therapy is often 48 weeks for C and 16 weeks for B. Detailed instructions on self administration will be given by a nurse when you first begin. Your first injection will be observed by the nurse for proper technique and for side-effects. |
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| What Are The Side-Effects? |
The most common if not universal symptom is that of flu-like symptoms with the first few injections. These can be lessened by pretreatment with Tylenol and giving injections late in the evening so you sleep through them. Fortunately, these resolve after a few weeks. A common and more serious side effect is depression, particularly if there is a history of depression in the past. If you suffer depression or develop depression on therapy, be sure to inform your doctor.
Changes in your blood counts can occur and sometimes can be severe. So you will have frequent lab test done to monitor these values and adjust or stop treatment if necessary. Severe changes in your blood values could predispose you to infections and/or bleeding. Rarely, in less than 1% of cases, your thyroid gland may become over or underactive. This will also be monitored by blood tests. Extreme fatigue or insomnia, irritability, or excessive sweating may be signs of these problems. Other troublesome side effects may include nausea, diarrhea, thinning of hair, irritation at injection site and weight loss. For the most part these are reversible with time and occasional withholding of the medication. |
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| What's The Expected Cure Rate? |
So called "cures" remain disappointing. While 50% of Hepatitis C patients will normalize their liver blood tests on medication, 50% of those will relapse once the drug is stopped - for a cure rate of only 25%. Though this is not great (and new dual therapies are being evaluated), it is better than the less than 10% chance of spontaneous remission without medication. If you suffer a relapse, readministering Interferon for longer periods of time may allow for a 10-15% chance of long term remission.
Hepatitis B is associated with a 35% response rate as defined by normalization of liver enzymes and loss of markers of active viral infection. Such a response signifies a decrease in your ability to spread the virus to others and also a decrease in the liver damage associated with viral infection - conversion to the so called healthy carrier state. Note: complete elimination of the Hepatitis B virus is rare. |
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| What If You Don't Take Interferon? |
The natural history of Hepatitis C is just now being worked out. We do believe that in most patients the disease progresses slowly over years to decades. The average time from infection to serious disease is 10 years. Liver cirrhosis takes about 20 years and an increased risk of liver cancer is seen after about 30 years. Note that some patients may have more rapidly progressive disease with cirrhosis within 3 to 5 years from onset of infection. A liver biopsy is often helpful to stage the disease, evaluate the amount of inflammation and likelihood of progressive disease. A repeat biopsy may be recommended in 2 to 3 years for patients with mild changes for whom Interferon has not been recommended, or in those who choose not to have therapy. Abstinence from alcohol plays an important role in treatment.
Hepatitis B infection is a more aggressive illness with progression to cirrhosis over years rather than decades. Patients who are candidates for Interferon with chronic active hepatitis due to hepatitis B should strongly consider a course of therapy. |
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| The Future |
| Scientific studies are ongoing with combination therapy involving two antiviral drugs given simultaneously. Preliminary trials are encouraging with increased response rate and fewer relapses. In time we may be able to eradicate these infections with the same predictability and success rates that we now see with antibiotics for bacterial infections. |
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Managing Side Effects Of Therapy |
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Tylenol or ibuprofen can be used to prevent or relieve fever and headache. |
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Bedtime or early evening injections may allow you to sleep through flu-like symptoms. |
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Conserve your energy - get plenty of sleep. |
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Drink plenty of fluids before and during therapy - at least 6 glasses daily. |
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Eat balanced meals with an adequate intake of calories. |
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Focus on the positive. |
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