A 68-year-old man with advanced metastatic lung cancer has severe constant chest pain despite regular oral Paracetamol. He is opioid-naïve. Renal function is normal. What is the most appropriate next step in analgesia?AStart high-dose IV Morphine as needed onlyBStart regular oral Morphine modified-release with oral immediate-release Morphine for breakthrough painCUse only non-opioid adjuvants such as AmitriptylineDGive a single stat dose of PethidineEAvoid opioids due to addiction riskCheck my answer