Cosentyx is a human monoclonal antibody, which is a man-made protein that may degrade (breakdown) if it has been left out of the refrigerator or exposed to heat, sunlight, or extreme cold. Even shaking Cosentyx may cause degradation. It is very important that you store your Cosentyx pen or prefilled syringe correctly in the refrigerator at 2ºC to 8ºC (36ºF to 46ºF) until you need to use it.