I often hear nurses advising the physicians to change the PRN order (or “as needed” order) to a scheduled order so that the medication will be administered consistently. However, doing so also defeats the purpose of ordering as PRN.  PRN orders (“as needed” or “pro re nata” orders) are not meant  to be given routinely but only as needed for the specific reason, symptom or indication. This often applies to analgesics for pain relief and antipsychotics for behavioural and psychological symptoms in dementia. It also applies to other medications meant for symptoms management based on the nursing assessment such as scopolamine for excessive secretions, dimenhydrinate for nausea and vomiting and laxatives for constipation.  

By ordering the medication routinely, it bypasses the nursing assessment that is critical to determine if the medication is effective, if it is causing any  side effects or sometimes…. whether therapy requires optimization or tapering.

So why is it so difficult to order PRN and to execute these orders accurately and consistently by nurses?

There are many reasons. For one, it takes more time to administer.  Pizzi LJ et al. conducted a nursing time study for the administration of a PRN oral analgesic on an orthopedic postoperative unit.  In this study, the authors have determined that it took a mean time of 10.9 minutes to administer PRN analgesics on the unit.  If a unit with 30 patients all require an administration of one PRN dose, it would take at least 300 minutes or roughly 5 hours for the task!

It takes efforts.  It requires initial assessment, documenting the findings, deciding whether the PRN medication should be given, then give the medication and follow up to assess the effectiveness of the medication. In the same study by Pizzi LJ et al, the authors have determined that the following tasks were required when giving a PRN analgesic:

  1. Answer patient call
  2. Get pain medication
  3. Bar code + pain score + give med
  4. Reassess pain
  5. Return next task

In other units, the process may be different. For instance, patients with dementia may not be able to verbalize pain as easily, relying more on nurses and personal support workers for their observations and findings.  Depending on the facility or institution, there may be formalized pain assessment tool to complete, or behaviour monitoring tools that also take additional time to complete.

Pain is subjective. One nurse may feel the pain is severe and requires analgesics but another may perceive it as minor and only require non-drug measure. For behaviour and psychological symptoms of dementia, one nurse may find the chanting to be disruptive whereas another nurse may not be bothered by the noise. At times, it is unclear how the order should be executed. Sometimes, a patient may present with agitation as a result of untreated pain. So how do you determine if it is analgesic that is needed or antipsychotics to help calm the patient?

Gordon DB et al. have evaluated nurses’ opinions on appropriate administration of PRN range opioid analgesic orders for acute pain.  The authors have concluded there are significant variations in how nurses interpret dose range orders as well as determining the appropriate timing of administration.  The nursing practices were influenced by their opinions of order limits and knowledge of opioid titration.

So it may be easy to write a PRN order but there are many logistics, nursing and patient specific considerations that one should be aware of. It definitely requires more time and effort to administer but PRN orders are an important part of the overall management for the patient’s symptoms.

Here are few of my thoughts on ensuring PRN medications are administered as intended:

  • Write simple PRN orders. That’s not to say one should not write more complicated PRN orders involving dose range, time range and daily limits (e.g. Give Morphine 1-2mg q2-4h PRN Max 10mg/day). The greater the complexity of the order, the greater the chance that it may be interpreted inconsistently. If such an order will be written, additional education, training and communication may be necessary to ensure orders are correctly interpreted and understood.
  • Discontinue any unnecessary PRN orders.  Sometimes, PRN orders are left as active just because no one knows for sure if the patient may need the medication or not. If it has not been given for the last 3 months (e.g. in a nursing home) or they were part of some standing orders during the hospital admission that are no longer relevant, they should be discontinued to minimize confusion.
  • Provide clear indication(s) for PRN orders (e.g. hydromorphone 1mg po q6h PRN for pain score greater than 6, risperidone 1mg po daily PRN for hallucination). If clear reasons are given when the patient may require PRN orders, then nurses will understand exactly when these orders are to be administered.
  • Establish Objective tools for assessment.  The institution may want to determine one or two valid assessment tools to use for symptoms assessment. There are many pain assessment tools available. Some are long and research focused. Others are practical. It doesn’t matter which tool is decided, the key is that all nurses agree they can and will utilize the tool to ensure objective assessment for their patients.
  • Indicate when therapy should be evaluated.  Not all PRN orders are ongoing. When clinical status changes or symptoms improve, the PRN orders may not be necessary and should be discontinued promptly.  Likewise, some PRN orders should be optimized to be given routinely for optimal symptom management.
  • Any new and current PRNs should be clearly communicated during hand over to incoming nurses and relevant care providers (e.g. personal support workers) One of my pet peeves is that nurses and personal support workers don’t realize what PRN medications are available for symptoms management. If the existing medication administration system does not allow everyone to be aware of the PRNs, make a point to communicate these options to all relevant care providers.
  • Order PRN Judiciously. Finally, it is more time consuming and takes more effort to administer PRN medications. Clinicians should be cognizant of these challenges when writing PRN orders.  And write them judiciously.

I hope you find this post useful and thank you for reading my post!