PRN and time-sensitive medicines

PRN medicines are prescribed to be taken when needed for symptoms such as pain, nausea, constipation, indigestion, anxiety, insomnia or breathlessness. Time-sensitive medicines must be given at the correct time for safety or to achieve the intended effect.

CQC's England PRN guidance expects services to have a PRN policy and a person-centred care plan that gives staff the information they need to give the medicine as the prescriber intended.

A strong PRN protocol should tell staff

• What it is for: the symptom or condition the medicine treats.
• When to offer it: signs, symptoms, cues or the person's own request.
• How much to give: exact dose or clear variable-dose rules.
• How often: minimum interval between doses and maximum in 24 hours.
• What else to try: comfort, repositioning, fluids, activity, reassurance or other non-medicine support where appropriate.
• What to record: reason, dose, time, effect and whether further advice is needed.
• When to escalate: ineffective relief, frequent use, non-use, confusion about dose, side effects or concern about overuse.

Examples of time-sensitive medicines include drugs that must be taken with or without food, medicines containing paracetamol, Parkinson's disease medicines, antibiotics, insulin, warfarin and medicines that should be taken at the same time each day. Parkinson's medicines are especially time-critical; CQC guidance advises that levodopa should be given within 30 minutes of the person's prescribed administration time.

PRN does not mean "give whenever". It means give according to a clear plan, record why it was given and check whether it worked.