In clinical studies, the most common side effects or adverse effects with Rebif were injection site reactions, headache, flu-like symptoms, fatigue, leukopenia (low levels of leukocytes, a type of white blood cell that plays a role in the immune system), fever, and impaired liver function. Common side effects that occurred with Rebif in one study are shown in the table below, as well as the percentage of Rebif and placebo patients who were affected by each. The most common serious adverse effects with Rebif included depression and suicidal thoughts, or attempted suicide. Depression of any severity occurred in about 25% of people who received Rebif and a similar percentage of people who received placebo.
Adverse effects in a study of Rebif in MS
|Injection site reactions||39%||89%||92%|
|Abnormal hepatic function||2%||4%||9%|
Because flu-like symptoms are common with interferon beta medications like Rebif, talk to your doctor about taking an over-the-counter medication, such as acetaminophen (Tylenol) or ibuprofen (Advil), 30 minutes before your Rebif injection to help control these symptoms.
Warnings and precautions
Allergy and hypersensitivity. Rebif should not be taken by persons who have had an allergic reaction to an interferon beta medication, such as itching, hives, difficulty breathing difficulty, and flushing, or a history of hypersensitivity to albumin.
Depression and suicide. Like other interferon beta medications, Rebif can cause depression and suicidal thoughts. If you experience depression or other mental illness while taking Avonex, report these symptoms to your doctor. If your depression or other psychiatric symptoms are severe, you should consider stopping Rebif.
Liver function. Interferon beta medications, including Rebif, can affect liver function and a small number of people taking Rebif have developed severe liver damage. Therefore, it is necessary to have periodic blood tests to monitor liver function while taking Rebif.
Anaphylaxis. Anaphylaxis is an extreme, dangerous allergic reaction which occurs rarely with Rebif. If you experience an allergic reaction while taking Rebif, contact your doctor immediately.
Pregnancy and nursing. You should avoid becoming pregnant while taking Rebif, as it may cause miscarriage. If you should become pregnant while taking Rebif, stop taking the drug immediately and talk to your doctor. Talk to your doctor about whether you should breast feed while taking Rebif, as it is not known whether Rebif is passed through breast milk or if it can harm your baby.
Seizures. If you have a seizure disorder, such as epilepsy, you should use Rebif with caution. Interferon beta medications, like Rebif, may cause seizures.
Thyroid function and blood testing. Rebif may cause problems with your thyroid gland, so periodic blood tests to monitor thyroid function are important when taking Rebif. Additionally, Rebif may cause decreases in white blood cell counts, so it is important to have regular blood tests to monitor for potential changes.
No formal studies have been conducted to examine drug interactions with Rebif. However, due to the potential for Rebif to cause neutropenia (low levels of a type of white blood cell called a neutrophil) and lymphopenia (low levels of neutrophils, a type of white blood cell), people who take Rebif with drugs that suppress the ability of bone marrow to produce blood cells, or myelosuppressive agents, should be closely monitored. Rebif should be used with caution in combination with drugs that can also impair liver function.