Three examples of strong painkillers only available on a doctor's prescription. Lyrica (pregabalin) is an antiepileptic medicine which is also used to treat neuropathic pain caused by nerve sensitivity or nerve damage such as shingles or sciatica. Amitriptyline, which is an tricyclic antidepressant medicine, is also used in smaller doses to relieve nerve pain. Codeine phosphate is an opioid analgesic which is prescribed to relieve moderate to severe pain. Continued use for long periods is not advised as opioids are highly addictive