Interferon and ribavirin are very strong drugs and both have potential side effects. Not everyone experiences these side effects, but it is rare for someone to have none at all. You should expect to get at least a few, particularly at the beginning. The list below sets them out and rates them as common, less common, and rare.
The list is practically the same for interferon (pegylated or standard) with or without ribavirin, since it is interferon that is the main cause. The exception to this is anaemia, which is a side effect of ribavirin. Because anaemia lowers the amount of oxygen carried around the body, particularly to the muscles, it tends to increase the fatigue that interferon causes.
Side effects that may require dose reduction or an end to treatment: |
| Anaemia (lowered levels of haemoglobin) | | common |
| Neutropenia (lowered levels of neutrophils, which are part of the immune system) | | common |
| Thrombocytopenia (lowered levels of platelets, which help blood to clot) | | common |
| Diabetes | | Less common |
Other side effects | |
| Flu-like symptoms, including | | | |
| Fatigue | | common | |
| Headaches | | common | |
| Fever (in the 48 hours following an interferon injection) | | common | |
| Shaking | | less common | |
| Muscular and joint aches | | common | |
| Dizziness | | less common | |
| | | | |
| Sight problems, including | | | |
| Retinal problems | | rare | |
| Blurred vision | | less common | |
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| Thyroid disease | | rare | |
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| Digestion/stomach symptoms, including | | | |
| Nausea | | common | |
| Decreased appetite | | common | |
| Diarrhoea | | rare | |
| Vomiting | | rare | |
| | | | |
| Mental symptoms, including | | | |
| Depression | | common | |
| Insomnia | | common | |
| Irritability/intolerance | | common | |
| Concentration difficulties | | common | |
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| Respiratory symptoms, including | | | |
| Coughing | | less common | |
| Difficulty breathing | | rare | |
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| Skin problems, including | | | |
| Hair loss | | common | |
| Pruritis (itching) | | common | |
| Rash | | less common | |
| Dry skin | | less common | |
