What are the side effects of tocilizumab?

In patients with rheumatoid arthritis, systemic juvenile idiopathic arthritis, juvenile idiopathic polyarthritis, giant cell arteritis, or cytokine release syndrome, the most common side effects of tocilizumab (which may affect up to 1 in 10 patients) are upper respiratory tract infection, nasopharyngitis, headache, hypertension, and liver function test abnormalities, and the most serious side effects are serious infection, diverticulitis complications, and allergic reactions. Among COVID-19 patients, the most common side effects (which may affect up to 1 in 10 patients) are high levels of aminotransferases in the blood (which may be a sign of liver problems), constipation, and urinary tract infections.