Avonex : Uses, Side effects, and Interactions

Research Based
Medically reviewed by - Dr Lara Mokhtar, MD Written by - Dr. Shaheen Shah


What is Avonex?

Avonex is a brand-name prescription drug to treat multiple sclerosis in adults. Multiple sclerosis is a persistent condition in which the body’s immune system wrongly attacks the myelin sheath protecting the brain and the spinal cord.

Avonex is a disease-modifying therapy. Disease-modifying therapy is a treatment that delays the progression of the multiple sclerosis disease.

Avonex is a brand-name prescription drug to treat multiple sclerosis in adults.

Key facts of Avonex

  • Avonex is an FDA (The Food and drug administration, United States) approved drug for treating the relapsing form of multiple sclerosis in adults. Relapsing is the getting back of the disease again, which can get worse.
  • Avonex is prepared from interferon. Interferons are human proteins the body’s immune system produces to fight infections.
  • Avonex is not available in biosimilar form(i.e., like generic drug form)
  • Avonex is not a cure for multiple sclerosis. It only decreases the occurrence of multiple sclerosis relapse symptoms 1Overview| Researched based study from

Category of drug

  • Avonex contains interferon beta-1a as the active ingredient.
  • Interferon beta-1a is the synthetic form of interferon
  • It is a biological drug made from the parts of the living organism.

Effectiveness of Avonex

In clinical trial studies of people with relapsing multiple sclerosis, Avonex was found to effectively control the following symptoms-

  • Decreased the number the relapses (return of disease symptoms)
  • Decreased the areas of nerve damage in the brain
  • Slowed the worsening of the disease 3Overview| Researched based study from


Dosage & formulations of Avonex

Avonex is injected once weekly, and the dosing increases weekly for up to four weeks. The doctor usually starts with a lower dose for first-time patients.

The commonly used doses of Avonex are as follows:

  • First week- 7.5 microgram (mcg) injection
  • Second week-15 mcg injection
  • Third week- 22.5 mcg injection
  • Fourth week and further-30 mcg injection 4Dosage| Researched based study from

However, one must always follow the dosage pattern the physician prescribes.

Mode of action

  • The mechanism by which Avonex works is still being determined. However, the drug is believed to enhance the body’s immune response to fight infections and reduce swelling and damage. Hence, it helps relieve the disease symptoms 2Dosage| Researched based study from

Formulations of Avonex

Avonex comes in the form of injections. The injections that come in single power (strength) of 30 micrograms are available in three forms:

  • Single-use prefilled syringe
  • Single-use prefilled auto-injector pen
  • Single-use vial of powder that is diluted with supplied sterilized water before giving the injection7Formulations| Researched based study from


Uses of Avonex

Avonex is used to treat the following conditions of multiple sclerosis. They are as follows:

Relapsing-remitting multiple sclerosis

  • Relapsing-remitting multiple sclerosis is the stage that is marked by new and worsening symptoms with periods of reduced or no symptoms in between.

Clinically isolated syndrome (CIS)

  • The clinically isolated syndrome is the individual’s first neurological attack caused by the swelling of the nerve tissue. It last for 24 hours and might indicate the start of multiple sclerosis.
  • CIS always does not result in multiple sclerosis.

Active secondary progressive multiple sclerosis

  • Active secondary progressive multiple sclerosis is the state that comes after relapsing-remitting multiple sclerosis and generally worsens with time 5Uses| Researched based study from

Side effects

Side effects of Avonex

Common mild side effects

  • Headache
  • Hair loss
  • Fever
  • Chill
  • Muscle pain
  • Chest pain
  • Joint pain
  • Lightheadedness
  • Nausea and vomiting
  • Pain at the injection site
  • Extreme tiredness
  • Urinary tract infection
  • Respiratory infection(viz; common cold)
  • Swelling of the sinuses

Serious side effects

  • Decreased platelet count
  • Liver damage
  • Thyroid problem
  • Nervousness
  • Depression
  • Severe injection site reaction
  • Itchiness
  • Skin rash
  • Reddening of the face
  • Swelling of the face, lip, mouth, and tongue
  • Seizures(sudden change in movement due to electrical activity in the brain)
  • Difficult breathing
  • Heart failure (heart unable to pump blood efficiently throughout the body) 6Side effects| Researched based study from

Overdose toxicity

  • One must never use more Avonex than the doctor’s prescribed dose, as excessive use might lead to serious side effects.
  • In case of accidental intake of too much Avonex, one should immediately dial the emergency contact number based on the geographical location or head off to the nearest emergency room 8Side effects| Researched based study from


Who should avoid taking Avonex ?

  • One must avoid people with chicken pox or measles infections as interferon might increase the chance of infection.
  • Pregnant women and nursing mothers should use the drug only after full clearance from a registered healthcare professional 9Contraindications| Researched based study from
  • Those with allergic reactions to the ingredient of the drug
  • People with an allergic reaction to rubber or latex
  • One with Mood disorders
  • With low blood count
  • With epilepsy(seizure) disorders
  • People with liver problem
  • One with heart problems
  • With thyroid problems
  • People with bleeding disorders
  • People with alcohol use disorder 10Contraindications| Researched based study from


Interactions of Avonex

To date, there is a little description of the interaction of Avonex with other drugs.

Some of the drugs that might interact with Avonex are as follows:

  • Atorvastatin(cholesterol-lowering drug)
  • Ibuprofen(a drug for relieving fever and pain)
  • Lisinopril(high blood pressure medication)
  • Tramadol(severe pain-relieving medication)
  • Tizanidine(a drug for relieving muscle spasms)
  • Simvastatin(cholesterol-lowering drug) 11Interactions| Researched based study from

However, it has every possibility that interactions might occur with other drugs not listed above. So, patients with medical conditions must always inform the doctor about it before consuming the drug.


Tips for administering Avonex

Ways of Administration

  • Avonex is administered intramuscularly (in the muscles)
  • Patients who are self-injecting must take prior proper training from a health professional and follow the instructions as directed before administering
  • One must avoid injecting the drug at the same site of injection to prevent the injection reaction site
  • One must take out the Avonex pen or prefilled syringe from the freeze 30 minutes before administration and allow it to come to room temperature
  • One should check the injection site after 2 hours for any swelling, tenderness, and redness
  • If swelling and tenderness do not clear up within a few days, one must immediately contact the health care professional.

Cost and availability

  • The cost of Avonex depends on several factors, such as geographical location, insurance coverage, and the health store for purchasing.
  • Avonex might be expensive without insurance coverage.
  • One can only purchase Avonex from specialty health stores authorized to keep specialty medications.


Storage and disposal of Avonex


  • One can keep Avonex in the refrigerator at a 2 to 8 degrees centigrade temperature range.
  • One must take an Avonex vial or injectible pen from the refrigerator only 30 minutes before administration. Once removed, one should not keep it in the fridge and must use it within seven days.
  • One must not keep the vial, syringe, or pen under direct sunlight after removal from the freeze.
  • However, if refrigeration is unavailable, one can keep the Avonex pen and prefilled syringes at room temperature (25 degrees centigrade) for up to 7 days.
  • One can keep Avonex vials at room temperature (25 degrees centigrade) for about 30 days 12Storage| Researched based study from


  • One must dispose of the syringe and needles in a trash container
  • One must dispose of the unused medication safely in the trash to prevent accidental consumption by young kids and pets
  • One must dispose of any medicine whose expiry date has crossed


Key Takeaways

  • Avonex is an FDA-approved drug for multiple sclerosis
  • Avonex is one type of treatment for managing multiple sclerosis
  • Before self-administering the injection at home, one must first learn the injecting process and instructions from a healthcare professional
  • One must take the exact dose as prescribed by the health care professional to prevent unwanted side effects
Disclaimer: The user acknowledges that this article's information is being offered for informational purposes only. Every attempt has been made to guarantee that the article is informational and correct. If they have any doubts or questions about their health, we firmly advise our readers to visit a doctor or other healthcare professional.

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