 Headaches are very common adverse effects, occurring in more than 10% of people who take the drug.Common adverse effects (occurring in between 1% and 10% of people who take the drug) include infections (pneumonia, upper respiratory tract infection, colds, and urinary tract infection), loss of white blood cells, loss of red blood cells, anaphylactic reaction, hypersensitivity reaction, loss of appetite, mood changes like depression and anxiety, a sense of tingling or numbness, blurred vision, vertigo, ringing in the ears, heart palpitations, high blood pressure, low blood pressure, vascular damage, peritonitis, constipation, upset stomach, swollen belly, itchy skin, increased sweating, blotches from small bleeds under the skin and skin redness, hives, muscle spasms, bone pain, back pain, neck pain, swollen joints, kidney damage, painful urination, spontaneous erections, general edema, chest pain, weakness, pain at the infusion site, and elevated transaminases.Eculizumab specifically binds to the terminal complement component 5, or C5, which acts at a late stage in the complement cascade.