A 70-year-old woman with a history of osteoporosis is admitted with a wedge fracture of L4. She has suffered a previous Colles fracture and a left fractured neck of femur and has been diagnosed with osteoporosis. She smokes 10 cigarettes per day. has a history of ischaemic heart disease, constipation and COPD. and was treated 4 weeks earlier for a bleeding duodenal ulcer. She is already taking regular paracetamol but is unable to mobilise due to pain.Investigations:<img src="https://up.zaixiankaoshi.com/9227692/question/c73955bd97027c7fdb8b6a91d1f568bf.png">Which of the following is the most appropriate additional option for analgesia?