Mild pain/swelling/bleeding at the injection site and chills may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor immediately if any of these unlikely but serious side effects occur: symptoms of liver damage (e.g., severe nausea/vomiting, stomach/abdominal pain, dark urine, yellowing eyes/skin).Rarely, this medication may increase the risk of developing cancer. Tell your doctor immediately if you develop symptoms such as: unusual lumps, swollen glands, skin sores/spots that are new or change appearance.This medication can lower the body's ability to fight an infection. Tell your doctor promptly if you develop any signs of an infection such as fever, muscle aches, or persistent sore throat.A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.