Insurance Coverage: Many major insurance plans no longer cover Avonex starting in 2016. Learn More
What should I watch for?
Tell your doctor or healthcare professional if your symptoms do not start to get better or if they get worse.
Visit your doctor or health care professional for regular checks on your progress. You will need frequent blood checks.
Flu-like symptoms are common with the medicine. Using this medicine at night may help. Ask your doctor or health care professional about taking acetaminophen or ibuprofen before your dose and for 24 hours after you receive your injection.
Do not become pregnant while taking this medicine. Women should inform their doctor if they wish to become pregnant or think they might be pregnant. There is a potential for serious side effects to an unborn child. Talk to your health care professional or pharmacist for more information.
Common and Rare Side Effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Black, tarry stools
painful or difficult urination
shortness of breath
sores, ulcers, or white spots on the lips or in the mouth
unusual bleeding or bruising
unusual tiredness or weakness
Abdominal or stomach pain
clumsiness or unsteadiness
difficulty with swallowing
feeling of warmth
mood changes, especially with thoughts of suicide
pain or discharge from the vagina
pelvic discomfort, aching, or heaviness
redness of the face, neck, arms, and occasionally, upper chest
redness, swelling, or tenderness at the injection site
runny or stuffy nose
swelling of the face, lips, or eyelids
general feeling of discomfort or illness
loss of appetite
painful blisters on trunk of the body
painful cold sores or blisters on the lips, nose, eyes, or genitals
Incidence not known
blood in the urine or stools
decreased urine output
dilated neck veins
dry skin and hair
fast, irregular, or pounding heartbeat
general tiredness and weakness
heavier menstrual periods
loss of bladder control
mood or other mental changes
muscle cramps and stiffness
nausea or vomiting
persistent loss of appetite
pinpoint red spots on the skin
puffiness or swelling of the eyelids, or around the eyes, face, lips, or tongue
redness, blistering, peeling, or loosening of the skin
sensitivity to heat
sudden loss of consciousness
swelling of the face, fingers, feet, or lower legs
swelling of the mouth or throat
tightness in the chest
tightness in the throat
upper right abdominal or stomach pain or tenderness
weight gain or loss
yellow eyes and skin
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.