Nausea, diarrhea, stomach upset, headache, dizziness, blurred vision, trouble sleeping, flu-like symptoms (e.g., fever, chills, sore throat, muscle aches), cough, hair loss, low appetite, weight loss or gain, dry skin, and changes in taste/hearing may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tooth and gum problems may sometimes occur during ribavirin/interferon treatment. Dry mouth can worsen this side effect. Prevent dry mouth by drinking plenty of water or by using a saliva substitute. Brush your teeth well at least twice daily and see your dentist regularly. If you experience vomiting during treatment, rinse out your mouth afterwards to reduce tooth and gum problems.
Tell your doctor right away if you have any serious side effects, including: unusual tiredness/weakness, fast/pounding/irregular heartbeat, trouble breathing, mental/mood changes (e.g., severe depression, thoughts of suicide or hurting others), muscle/joint pain, vision changes, easy bruising/bleeding, dark urine, yellowing of eyes/skin.
Get medical help right away if you have any very serious side effects, including: chest pain, jaw/left arm pain, stomach/lower back pain, black/bloody stools.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.