My most helpful "prn" or "take as needed" med is a pain med meant for quicker relief for breakthrough pain. It is hydromorphone. It is taken in addition to a daily pain meds which are taken 24/7. I am fortunate to have access to this med, as it has made life possible, often.
The oral doses are nothing like the IV form given in ERs or inpatient medical settings. Less potent.



DejaVu