Avonex is a prescription medication approved by the Food and Drug Administration (FDA) for adults who have had their first episode of multiple sclerosis (MS) symptoms and whose magnetic resonance imaging (MRI) scans are compatible with a diagnosis of MS. The drug name of Avonex is Interferon beta 1a, which is also sold under the brand name Rebif as a different formulation. Avonex is not a cure for MS, but it can decrease the number of flare-ups and help delay or prevent disability in people with relapsing forms of MS.
Avonex must be used with caution and closely monitored in people with a history of depression, seizures, or heart or liver problems. Avonex is not suitable for use by pregnant women, women who plan to become pregnant, or women who are breastfeeding. Avonex should not be taken by anyone allergic to interferon beta or to human albumin (a type of protein).
It is believed that Avonex works by reducing inflammation in the brain. It may also promote nerve growth.
How do I take it?
Avonex is given once a week as an intramuscular injection in the upper arm or upper or outer thigh. It is recommended to take Avonex before bedtime. You can learn to inject yourself, have a friend or family member learn how to inject you, or receive your injection from a medical professional. You should change to a different site each time you inject, and never inject into any part of the skin that is scarred, infected, bruised or irritated.
Avonex comes in three different formats. It can come in a prefilled syringe; in a single-use autoinjector pen; or in a single-use vial with freeze-dried powder that must be mixed before it is injected. Your doctor will help you select which format is best for you. All forms of Avonex should be kept refrigerated until use and allowed to warm to room temperature before injection.
When you begin taking Avonex, your doctor will gradually increase the dosage each week over four weeks. Before or during your treatment with Avonex, your doctor may order extra blood tests to monitor your liver function and blood cell counts.
Always follow your doctor’s instructions exactly when taking Avonex.
Interferon beta 1a (Avonex) was approved by the FDA based on the results of two clinical trials. The results of the studies showed that Interferon beta 1a reduced relapses by 32 percent in those who took it for two years, decreased the risk of relapse by 44 percent after three years in those who began taking it after their first flare-up, and lowered the risk of disability progression by 37 percent.
It is very common to experience flu-like symptoms during the first few days of taking Avonex. Over-the-counter pain relievers can be taken to ease the discomfort.
Some people taking Avonex experience mood or behavioral problems including depression, suicidal thoughts, anxiety, irritability or hallucinations.
Some people on Avonex develop liver problems or experience a worsening of existing liver problems. Signs of liver problems can include jaundice (yellowing of the white part of the eye), nausea, loss of appetite, dark urine and pale feces, and bleeding more easily than usual.
Avonex can also cause allergic reactions. Get medical help immediately if you experience difficulty breathing or swelling in the face, throat, eyes, lips, or tongue.