De mest alvorlige bivirkninger er gastrointestinale perforationer (huller i tarmen), fistler (unormale røragtige forbindelser mellem organerne), blødning og arteriel tromboemboli (blodpropper i arterierne).
The most serious side effects are gastrointestinal perforations (holes in the gut), fistulae (abnormal tube-like connections between organs), haemorrhage (bleeding), and arterial thromboembolism (blood clots in the arteries).