Injection site reactions (pain/swelling/redness), diarrhea, upset stomach, nausea, or vomiting may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
Flu-like symptoms such as headache, tiredness, fever, chills, and muscle aches may occur, especially when you first start this medication. These symptoms usually last about 1 day after the injection and improve or go away after a few months of continued use. You can reduce these side effects by injecting this medicine at bedtime and using a fever reducer/pain reliever such as acetaminophen before or after each dose. Consult your doctor or pharmacist for more information.
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 right away if you have any serious side effects, including: lightheadedness, fainting, mental/mood changes (e.g., confusion, depression), shaking (tremors), trouble walking, slow/fast/irregular heartbeat, shortness of breath, swelling of the ankles/feet, increasing tiredness, joint pain, butterfly-shaped rash on the face, easy bleeding/bruising, persistent nausea/vomiting, seizures, signs of infection (e.g., fever, persistent sore throat), stomach/abdominal pain, black/tarry stools, dark urine, change in the amount of urine, yellowing eyes/skin.
Get medical help right away if any of these rare but very serious side effects occur: chest/jaw/left arm pain, weakness on one side of the body, slurred speech, sudden vision changes, pain/redness/swelling of the arms/legs, calf pain/swelling that is warm to the touch, coughing up blood.
A very serious allergic reaction to this drug is rare. However, get medical help right away 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.