Pro re nata*is a*Latin*phrase meaning*in the circumstances*or*as the circumstance arises.[1]*It is commonly used in*medicine*to mean*as needed*or*as the situation arises. It is generally abbreviated to*in reference to dosage of*prescribed*medication that is not scheduled; instead, the decision of when to administer the drug is left to the*nurse,*caregiver*or the patient's prerogative.[2]*Such administration of medication is not meant to imply, and should never allow for, exceeding a given daily dosage.