The strongest prescription pain killer is morphine, as stated by NHS. Morphine is in the group of painkillers called opioids or opiates. There are both weak and strong opioids that a doctor may prescribe, depending on a person's condition.
Typically, opioids form the strongest group of pain killers. Some of the weak opioids include dihydrocodeine and codeine. Strong opioids include pethidine, morphine, methadone, diamorphine, tramadol, fentanyl and oxycodone, among others. Usually, a doctor will first give a patient weak painkillers, such as ibuprofen or paracetamol. If they do not work, he or she will prescribe opioids to a patient, as stated by Patient.