Commonly reported reactions are nausea, anxious sweating, dizziness, itchy skin, redness and or swelling of injection site, palpitations (a fast or fluttering heart beat) and facial flushing (may also include arms and torso), but should disappear within a few hours.[1][2] Rarely seen, but serious side effects include rash, fainting, headache, blurred vision, severe swelling, severe dizziness, trouble breathing, irregular heartbeat.[6]