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Avonex Side Effects

Generic Name: interferon beta-1a

Note: This page contains information about the side effects of interferon beta-1a. Some of the dosage forms included on this document may not apply to the brand name Avonex.

In Summary

Common side effects of Avonex include: flu-like symptoms, fever, headache, myalgia, nausea, and chills. Other side effects include: anemia. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to interferon beta-1a: kit, solution

In addition to its needed effects, some unwanted effects may be caused by interferon beta-1a (the active ingredient contained in Avonex). In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking interferon beta-1a:

More common:
  • Black, tarry stools
  • chest pain
  • chills
  • cough
  • diarrhea
  • fever
  • flu-like symptoms
  • headache
  • joint pain
  • muscle aches
  • nausea
  • pain
  • painful or difficult urination
  • shortness of breath
  • sores, ulcers, or white spots on the lips or in the mouth
  • swollen glands
  • unusual bleeding or bruising
  • unusual tiredness or weakness
Less common:
  • Abdominal or stomach pain
  • clumsiness or unsteadiness
  • convulsions (seizures)
  • decreased hearing
  • difficulty with swallowing
  • dizziness
  • fainting
  • feeling of warmth
  • hives or itching
  • mood changes, especially with thoughts of suicide
  • muscle spasms
  • 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
  • skin lesions
  • sneezing
  • sore throat
  • speech problems
  • swelling of the face, lips, or eyelids
  • troubled breathing
Rare
  • Earache
  • 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:
  • Bleeding gums
  • blood in the urine or stools
  • bloody nose
  • chest discomfort
  • confusion
  • constipation
  • dark urine
  • decreased urine output
  • depressed mood
  • dilated neck veins
  • dry skin and hair
  • extreme fatigue
  • fast, irregular, or pounding heartbeat
  • feeling cold
  • general tiredness and weakness
  • hair loss
  • heavier menstrual periods
  • high fever
  • irregular breathing
  • light-colored stools
  • loss of bladder control
  • mental depression
  • mood or other mental changes
  • muscle cramps and stiffness
  • nausea or vomiting
  • nervousness
  • pale skin
  • 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
  • skin rash
  • slowed heartbeat
  • sudden loss of consciousness
  • sweating
  • 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

Minor Side Effects

Some of the side effects that can occur with interferon beta-1a may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common:
  • Heartburn
  • indigestion
  • sour stomach
Less common:
  • Hair loss
  • trouble sleeping

For Healthcare Professionals

Applies to interferon beta-1a: intramuscular kit, intramuscular powder for injection, subcutaneous kit, subcutaneous solution

General

Influenza-like symptoms (e.g., myalgia, fever, chills, sweating, asthenia, headache, nausea) are the most common adverse reactions.[Ref]

Hematologic

Very common (10% or more): Lymphopenia (14%), leukopenia (11%), neutropenia, thrombocytopenia, anemia
Common (1% to 10%): Neutrophil count decreased, hematocrit decreased, blood potassium increased, blood urea nitrogen increased
Uncommon (0.1% to 1%): Platelet count decreased
Rare (Less than 0.1%): Thrombotic microangiopathy including thrombotic thrombocytopenic purpura/hemolytic uremic syndrome,
Frequency not reported: Pancytopenia[Ref]

Gastrointestinal

Very common (10% or more): Nausea (27%), diarrhea (17%), constipation (12%), vomiting (10%)
Common (1% to 10%): Abdominal pain, toothache
Frequency not reported: Dry mouth, dyspepsia[Ref]

Dermatologic

Very common (10% or more): Skin rashes (25%), increased sweating
Common (1% to 10%): Contusion, pruritus, erythematous rash, maculopapular rash, night sweats
Uncommon (0.1% to 1%): Alopecia, allergic dermatitis, erythema, urticaria
Rare (0.01% to 0.1%): Skin ulceration/necrosis at the site of injection, Quincke's edema (angioedema), erythema multiforme, Stevens-Johnson syndrome
Very rare (less than 0.01%): Calcified subcutaneous nodules, psoriasis, periungual and nail alterations
Frequency not reported: Rash vesicular[Ref]

Endocrine

Uncommon (0.1% to 1%): Hypothyroidism, hyperthyroidism[Ref]

Cardiovascular

Frequency not reported: Cardiomyopathy, congestive heart failure, palpitations, arrhythmia, tachycardia, vasodilatation, chest pain, pulmonary arterial hypertension (PAH) (sometimes reported up to several years after starting treatment)[Ref]

Genitourinary

Very common (10% or more): Urinary tract infection (19%), cystitis (11%)
Frequency not reported: Metrorrhagia, menorrhagia, urinary incontinence, increase in the frequency of micturition[Ref]

Hepatic

Very common (10% or more): Alanine aminotransferase increased (26%), aspartate aminotransferase increased (16%)
Common (1% to 10%): Gamma-glutamyl-transferase increased
Uncommon (0.1% to 1%): Hepatitis (with or without icterus)
Rare (Less than 0.1%): Hepatic failure, autoimmune hepatitis
Frequency not reported: Elevation of hepatic transaminases (SGPT and SGOT), bilirubinemia, jaundice[Ref]

Hypersensitivity

Rare (Less than 0.1%): Anaphylactic reactions
Frequency not reported: Other allergic reactions[Ref]

Immunologic

Very common (10% or more): Influenza-like symptoms (49%)
Frequency not reported: Systemic lupus erythematosus, anaphylactic reaction, anaphylactic shock, hypersensitivity reactions (angioedema, dyspnea, urticaria, rash, pruritic rash)[Ref]

Local

Very common (10% or more): Injection site erythema (62%), injection site pain (15%), injection site pruritus (13%), injection site bruising
Common (1% to 10%): Injection site edema, injection site warmth, injection site hematoma, injection site rash
Uncommon (0.1% to 1%): Injection site infections (which could be severe)
Rare (Less than 0.1%): Injection site cellulitis (which could be severe)
Frequency not reported: Injection site abscess, injection site reaction, injection site inflammation, injection site necrosis, injection site bleeding[Ref]

Musculoskeletal

Very common (10% or more): Myalgia (19%), back pain (20%), pain in extremity (19%), arthralgia (16%), muscular weakness (12%), muscle spasms (10%)
Common (1% to 10%): Muscle spasticity, muscle cramp, neck pain, arthralgia, muscle stiffness, musculoskeletal stiffness
Rare (0.01% to 0.1%): Drug induced lupus erythematosus
Frequency not reported: Arthritis[Ref]

Nervous system

Very common (10% or more): Headache (67%), dizziness (16%), paresthesia (12%)
Common (1% to 10%): Hypoesthesia
Uncommon (0.1% to 1%): Facial hypoesthesia
Frequency not reported: Neurological symptoms, syncope, hypertonia, seizures, migraine[Ref]

Metabolic

Frequency not reported: Weight decreased, weight increased[Ref]

Ocular

Common (1% to 10%): Eye pain
Uncommon (0.1% to 1%): Retinal vascular disorders (i.e. retinopathy, cotton wool spots, obstruction of retinal artery or vein)
Frequency not reported: Eye disorder, abnormal vision, xerophthalmia[Ref]

Other

Very common (10% or more): Pyrexia (45%), asthenia (24%), pain (23%), fever (20%), chills (19%)
Common (1% to 10%): Fatigue, malaise, hyperthermia, vertigo
Frequency not reported: Tachyphylaxis, sudden hearing loss, tinnitus (ototoxic effects resolved 7 to 14 days after discontinuation of the drug)[Ref]

Psychiatric

Common (1% to 10%): Depression/suicidal ideation, insomnia, somnolence
Uncommon (0.1% to 1%): Anxiety
Frequency not reported: Suicide attempt, suicide, psychosis, anxiety, confusion, emotional lability, anhedonia, psychotic thoughts, mood disturbances, hypersexuality, aggressive behavior, panic attacks[Ref]

Respiratory

Very common (10% or more): Oropharyngeal pain (28%), nasopharyngitis (24%), upper respiratory tract infection (21%), cough (16%), sinusitis (14%)
Common (1% to 10%): Rhinorrhea, bronchitis
Rare (0.01% to 0.1%): Dyspnea
Frequency not reported: Pulmonary arterial hypertension[Ref]

Renal

Rare (Less than 0.1%): Nephrotic syndrome, glomerulosclerosis[Ref]

References

1. "Product Information. Rebif (interferon beta-1a)." Serono Laboratories Inc, Norwell, MA.

2. "Product Information. Avonex (interferon beta-1a)." Biogen, Cambridge, MA.

3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

4. Cerner Multum, Inc. "Australian Product Information." O 0

Not all side effects for Avonex may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.

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