Pro re nata or PRN is the Latin term used in medical sciences for the administration of medications only at the time of need.
People who are admitted to the hospital may sometimes notice in their hospital files that the medication orders are sometimes written with PRN orders.
PRN medications are medicines that are not used regularly in a day or in regular doses. They are only administered at the time of need. Whenever a medication has to be prescribed as PRN, it is mentioned clearly so the nurses can administer it only when an indication arises.
PRN medication is usually prescribed for a very short duration or in the case when intermittent intervention or management is required. We only give them in specific situations or a specific times.
Examples of PRN medications
Some of the most commonly prescribed medicines on a PRN basis are non-steroidal anti-inflammatory drugs and other analgesics. Some analgesics are known to be irritating gastric mucosa and they must be avoided for the same reason. PRN is the option in such cases. Some nighttime sedatives are also used on a PRN basis and regular intake is not recommended.
Laxatives are the drugs used for treating constipation. So, laxatives are also prescribed on a PRN basis because there is no indication for such drugs to be used on a regular basis. They are used only when a patient is complaining of constipation or gut motility is low for some reason. Once, the symptoms are relieved, these medications are discontinued.
What are the advantages of PRN medications?
PRN medications are especially advantageous if the patient needs some treatment for the long term and his physician is also interested in preventing the possible side effects of the drug as much as possible. It is also good to avoid unnecessary and excessive use of medications.
What is the protocol for administering PRN medications?
In medical practice, there is always a code for any practice. For PRN medication, there is always charting and this charting contains information about the nature of the prescription, complaints of the patient, and administration of medication at the time of need.
According to the PRN medication protocol, it is very important that a PRN medication record sheet contains the following information.
- The proper and clear name of the medication is important to mention. It is good if the generic name is mentioned.
- The proper dose of medication in milligrams or grams
- The route of administration must be mentioned very clearly. It is important to mention the route from which medicine has to be given.
- The frequency of medication is also mentioned. This also explains the maximum dose of the drug in a day.
- It is also important to mention the interval between the medication and the maximum dose which is allowed in a PRN order.
We can comprehend a PRN medication with an example. A patient, for example, complains of excessive pain after Surgery and the doctor is interested in giving PRN medicine. So he will mention that a tablet of paracetamol 1000 mg per oral can be given on a PRN basis only thrice a day.

