What are the possible side effects of abarelix?

In some cases, the use of abarelix has resulted in serious allergic reactions. An allergic reaction may occur after any injection of the medication, including, but not limited to the first dose. Patients should be observed in the doctor's office for at least 30 minutes following each dose so that immediate treatment of an allergic reaction can be obtained if needed.

Other, less serious side effects may be more likely to occur. Talk to your doctor if you experience
hot flashes;
sleep disturbances;
breast enlargement or pain;
diarrhea or constipation;
swelling;
nausea;
dizziness;
headache;
fatigue; or
changes with or difficulty urinating.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.