Finding the proper words could. Writing your prescription as a PRN order essentially gives the patient the option to take the drug when needed. Pin On First Aid Emergency Medicine 25 Perfect Words to Help Describe Your Pain and Suffering. . Categories Etiquette advice. In that case your instructions would read Take 1 tablet by mouth every six hours as. Business Email Writing. Words to Friends. Lets say that you would like your patient to be able to take one 650 mg tablet of acetaminophen every six hours when he or she has a headache. It is never easy to find the right words to describe pain especially in different situations.