INTRON A- interferon alfa-2b 
Merck Sharp & Dohme Corp.



INTRON® A (In-tron-aye)
(Interferon alfa-2b, recombinant)

Read this Medication Guide before you start taking INTRON A, and each time you get a refill. There may be new information. This information does not take the place of talking with your healthcare provider about your medical condition or your treatment.

If you are taking INTRON A with REBETOL, also read the Medication Guide for REBETOL® (ribavirin) Capsules and Oral Solution.

INTRON A alone is a treatment for certain types of cancers and hepatitis B virus. INTRON A by itself or with REBETOL is a treatment for some people infected with hepatitis C virus.

What is the most important information I should know about INTRON A?

INTRON A can cause serious side effects that:

Tell your healthcare provider right away if you have any of the symptoms listed below while taking INTRON A. If symptoms get worse, or become severe and continue, your healthcare provider may tell you to stop taking INTRON A permanently. In many, but not all people, these symptoms go away after they stop taking INTRON A.

Heart problems. Some people who take INTRON A may develop heart problems, including:
  • low blood pressure
  • fast heart rate or abnormal heart beats
  • trouble breathing or chest pain
  • heart attacks or heart muscle problems (cardiomyopathy)
Stroke or symptoms of a stroke. Symptoms may include weakness, loss of coordination, and numbness. Stroke or symptoms of a stroke may happen in people who have some risk factors or no known risk factors for a stroke.
Mental health problems, including suicide. INTRON A may cause you to develop mood or behavior problems that may get worse during treatment with INTRON A or after your last dose, including:
  • irritability (getting upset easily)
  • depression (feeling low, feeling bad about yourself, or feeling hopeless)
  • acting aggressive, being angry or violent
  • thoughts of hurting yourself or others, or suicide
  • former drug addicts may fall back into drug addiction or overdose
If you have these symptoms, your healthcare provider should carefully monitor you during treatment with INTRON A and for 6 months after your last dose.
New or worsening autoimmune disease. Some people taking INTRON A develop autoimmune diseases (a condition where the body's immune cells attack other cells or organs in the body), including rheumatoid arthritis, systemic lupus erythematosus, sarcoidosis, and psoriasis. In some people who already have an autoimmune disease, the disease may get worse while on INTRON A.
Infections. Some people who take INTRON A may get an infection. Symptoms may include:
  • fever
  • chills
  • bloody diarrhea
  • burning or pain with urination
  • urinating often
  • coughing up mucus (phlegm) that is discolored (for example yellow or pink)

While taking INTRON A, you should see a healthcare provider regularly for check-ups and blood tests to make sure that your treatment is working and to check for side effects.

What is INTRON A?

INTRON A is a prescription medicine that is used:

Who should not take INTRON A?

Do not take INTRON A if you:

Talk to your healthcare provider before taking INTRON A if you have any of these conditions.

What should I tell my healthcare provider before taking INTRON A?

Before you take INTRON A, tell your healthcare provider if you:

Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. INTRON A and certain other medicines may affect each other and cause side effects.

Especially tell your healthcare provider if you take:

Know the medicines you take. Keep a list of them and show it to your healthcare provider and pharmacist when you get a new medicine.

How should I take INTRON A?

What are the possible side effects of INTRON A?

INTRON A may cause serious side effects including:

You may need to have a chest X-ray or other tests if you develop fever, cough, shortness of breath, or other symptoms of a lung problem during treatment with INTRON A.

Tell your healthcare provider right away if you have any of the symptoms listed above.

The most common side effects of INTRON A include:

Tell your healthcare provider if you have any side effect that bothers you or that does not go away.

These are not all the side effects of INTRON A. For more information, ask your healthcare provider or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

How should I store INTRON A?

INTRON A Solution for Injection:

INTRON A Powder for Injection:

Before mixing, store in the refrigerator between 36°F to 46°F (2°C to 8°C).

Keep INTRON A and all medicines out of the reach of children.

General Information about INTRON A

Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use INTRON A for a condition for which it was not prescribed. Do not give INTRON A to other people, even if they have the same symptoms that you have. It may harm them.

This Medication Guide summarizes the most important information about INTRON A. If you would like more information, ask your healthcare provider. You can ask your healthcare provider or pharmacist for information about INTRON A that was written for health care professionals.

What are the ingredients in INTRON A?

Active ingredient: interferon alfa-2b

Inactive ingredients:

Revised: 2/2016
Merck Sharp & Dohme Corp.