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When required (PRN) medicines

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Medicines with a PRN (pro re nata) or ‘when required’ dose can treat many different conditions.

Examples include nausea and vomiting, pain, indigestion, anxiety or insomnia.

People with long term conditions may also use when required medicines. For example, inhaled reliever medicines for people with asthma.

Care plans

A care plan should contain enough information to support staff to administer when required medicines as intended by the prescriber. This should include:

  • details about what the medicine is for
  • symptoms to look out for and when to offer the medicine
  • whether the person can ask for the medicine or if they need prompting or observing for signs of need. For example, non-verbal cues
  • when to review the medicine and how long the person should expect to take it
  • where there is more than one option available, the plan should make clear the order to try them. For example, when using multiple painkillers, you might try paracetamol first then codeine

Keep this information with the medicines administration record (MAR).

Care plans for when required medicines should be person-centred. They should detail how to offer the medicine (such as outside the normal medicine round). The plan should also tell your staff what records to make. For example, glyceryl trinitrate spray is occasionally used for chest pain in angina. You might record this only when needed.

Another example is pain relief that you assess at each medicine round. You might record this each time you assess it. Or you might only record when it’s given. This will depend on the requirements laid out in the care plan.


There should be a care home policy for when required medicines which includes:

  • the reasons for giving the when required medicine
  • how much to give if a variable dose has been prescribed
  • what the medicine is expected to do
  • the shortest time to wait between doses if the first dose has not worked
  • offering the medicine when needed and not just during medication rounds
  • when to check with the prescriber if there is any confusion about which medicines or doses to give
  • recording when required medicines in the resident's care plan

You would normally keep when required medicines in their original packaging.

Offer medicines in a person-centred manner. Offer the medicines to the person when they are experiencing the symptoms. Do not limit the offers to medicines rounds or times printed on MARs. Make a record of the exact time and the amount of medicine given.

Your records will show if you're regularly giving someone a when required medicine. If this happens, you should refer the person to the prescriber to consider a medicines review. The prescriber may need to change the person's treatment.

If medicines do not have the expected effects (such as effective pain relief), contact the prescriber.

Keep a record of responses from prescribers about queries to medicines.

Important points to consider

Does the medication policy and procedure cover the administration of when required medicines?

Do care plans provide detailed information on medicines prescribed as 'when required'?

Do staff understand what the medicines are for?

Do staff know when to give the medicine or ask the person if they need it? Do they know what symptoms to look out for? Is the maximum amount to be given in a day or the time to leave between doses recorded?

Are when required medicines given regularly? If so, has a medicines review taken place?

Are accurate records of administration made?

Are when required medicines held in suitable quantities and within their expiry dates?

Do you take a person-centred approach? Is the person offered the medicine at times other than the usual medication rounds?

Last updated:
02 December 2019