The two forms of interferon beta-1a (Avonex and Rebif) are taken differently. For Avonex, general considerations include the following:
- Avonex comes as an injection. It is injected into a muscle (intramuscularly) once a week.
- You can inject Avonex at any time of the day, although it should be injected at the same time each week.
- Avonex comes in prefilled syringes or in vials with dry powder that must be mixed first. If you will be using the vials, your healthcare provider should show you exactly how to mix the injection.
- If you and your healthcare provider desire, you (or a friend or relative) can give the Avonex injections. In this case, your healthcare provider should teach you exactly how to inject the drug.
- The best places to inject Avonex are in the thighs (either on the tops or sides) or the upper arm. If you give the injections to yourself, you will not be able to use the upper arm. You should rotate injection sites, which means that you should not inject the same part of the body two weeks in row.
- Never shake Avonex, even when mixing the vials. The medication is a delicate molecule that can be destroyed by shaking.
- For the medication to work properly, it must be taken as prescribed. Avonex will not work if you stop taking it.
For the other form, Rebif, general considerations include the following:
- Rebif comes as an injection. It is injected subcutaneously (just under the skin) three times a week. You will start at a low dose and slowly work up to a full dose.
- Inject Rebif on the same three days each week (for instance, Monday, Wednesday, and Friday), making sure there are at least 48 hours between injections. Try to take the injections at the same time of the day, preferably in the late afternoon or evening.
- It is best to inject Rebif into areas of the skin that have a layer of fat underneath. This includes the thigh, the outer upper arm, stomach (away from the navel), or buttocks. Try to rotate the injection sites (do not inject in the same place twice in a row).
- Make sure your healthcare provider teaches you exactly how to inject Rebif. This includes how to prepare the skin, how to insert the needle and inject the medication, and what to do with your used needles (this may vary, depending on the local laws and regulations).
- Rebif comes in prefilled, premeasured syringes with needles attached. The needles are very thin, as the injection just needs to go under the skin, not into muscle.
- For the medication to work properly, it must be taken as prescribed. Rebif will not work if you stop taking it.