REBIF/AVONEX (Interferon Beta-1a)

What is this medication?

REBIF/AVONEX (Interferon Beta-1a)
Interferon

REBIF/AVONEX (Interferon Beta-1a) is indicated for the treatment of relapsing forms of multiple sclerosis (MS), to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults.

How does this medication work?

The mechanism of action by which REBIF/AVONEX (Interferon Beta-1a) exerts its effects in patients with multiple sclerosis is unknown.

How should I take this medication? 

AVONEX:
IM: Inject 30 mcg intramuscularly once weekly; to decrease flu-like symptoms, may initiate once-weekly dosing with 7.5 mcg (week 1) then increase dose in increments of 7.5 mcg once weekly (weeks 2 to 4) up to recommended dose (30 mcg once weekly).

Rotate injection site. Do not inject into area where skin is irritated, red, bruised, scarred, or infected. Two hours after injection, examine site for redness, swelling, or tenderness. Discard any unused portion.

REBIF:
SQ: Target dose, inject either 22 or 44 mcg subcutaneously 3 times weekly; doses should be separated by at least 48 hours.

Administer at the same time of day on the same 3 days each week (eg, Mon, Wed, Fri), preferably in the late afternoon or evening. Rotate injection site, and do not inject into area where skin is irritated, red, bruised, or scarred. Discard any unused portion.

When first starting REBIF, it should be started at a low dose and tapered upwards. REBIF provides a titration kit that has numbered syringes for titration. The typical titration is as follows. Weeks 1-2 8.8 mcg three times a week Weeks 3-4 22 mcg three times a week Weeks 5+ 44 mcg three times a week.

Sites include the front of the thighs, back of arms, buttocks and abdomen.

How to Take: The first injection should be administered under the supervision of a health care professional.

What should I watch for while using this medication? 

Before starting REBIF/AVONEX (Interferon Beta-1a) make sure your physician is aware of any allergies and medications you currently take, if you have cardiovascular disease, liver disease, a seizure disorder, or thyroid dysfunction.  Interferon Beta-1A use has been associated with rare but serious adverse events such as hypersensitivity reaction, autoimmune disorder, bone marrow suppression, flu like symptoms, hepatic effects, injection site reaction, neuropsychiatric disorder, and thrombotic microangiopathy. 

Watch for signs/symptoms suggestive of liver dysfunction, such as loss of appetite accompanied by other symptoms such as malaise, fatigue, nausea, vomiting, abdominal pain, dark urine, jaundice or pruritus. 

Watch for flu-like symptoms (fever, headache, chills, muscle aches) are not uncommon following initiation of therapy with REBIF. Acetaminophen or ibuprofen may be used for relief of flu-like symptoms. 

You should contact your physician or pharmacist if you experience any of the above undesirable effects.

What size needle does this medication use?

REBIF
Prefilled syringe: 29-gauge, ½ inch needle

AVONEX
Prefilled syringe: 25-gauge, 1 inch needle
Autoinjector: 25-gauge, ⅝ inch needle

What is the difference between a prefilled syringe and a cartridge?

The prefilled syringe is in a ready to use format including a fixed needle, whereas a cartridge needle is separate from the glass body.

What if I miss a dose?

If you miss an injection, you should take your next injection as soon as you remember or are able to take it, then skip the following day and give your regular dose 48 hours later. Do not take Interferon Beta-1a on 2 consecutive days. If you accidentally take more than your prescribed dose, or take it on 2 consecutive days, call your healthcare provider right away.

How should I store this medication?

Keep out of the reach of children. Store in the refrigerator between 36°F to 46°F (2°C to 8°C). Keep in the original carton to protect it from light. Allow to warm to room temperature prior to use (do not use external heat source). 

What are the possible side effects of using this medication?

You may experience flu-like symptoms (fever, headache, chills, muscle aches) at the beginning of therapy which should decrease over time.  Acetaminophen or ibuprofen may be helpful in relieving flu-like symptoms. 

Note this is not a complete list of side effects for REBIF/AVONEX (Interferon Beta-1a), only common ones.