Thanks for your question. Co-codamol is a highly addictive drug and is not advised to take for a long. It can cause restlessness and irritation feeling when you are to stop using them. So, it is not advised to take it for more than three days at a stretch to avoid addiction and related side effects. Anyway, your doctor knows you better and can decide how long you may use it for the treatment of your illness. It is better to follow his directions strictly.