Error Alert
Institute for Safe Medication Practices, Horsham, PA
This month, we at ISMP wish to bring attention to two important problems we have encountered. These two possible medication errors, which involve issues with formulating and explaining dosages, have the potential to cause serious overdosages in patients but can be avoided with proactive planning and prescription labeling.
Topiramate oral solution concentrations
A new oral solution, Eprontia (topiramate—Azurity), was recently approved for the treatment of certain seizure disorders in patients 2 years and older as well as for the prevention of migraines in patients 12 years and older.
The concentration of this new product is 25 mg/mL, which differs from commonly compounded concentrations prepared by a pharmacy.
The American Society of Health-System Pharmacists’ Standardize 4 Safety Initiative and the Michigan Pediatric Safety Collaboration recommend 20 mg/mL as the standard concentration. However, some organizations compound 6 mg/mL for smaller children to make doses easier to measure.
We are concerned about the risk of errors as pharmacies transition patients to the new commercially available 25 mg/mL topiramate concentration. This is especially concerning for patients prescribed the 6 mg/mL concentration, as an error could lead to a significant overdose.
Organizations should establish a proactive plan to convert to the commercially available product. This plan should include identifying patients currently receiving an extemporaneous formulation of topiramate to ensure all active patients are converted to the new concentration in a defined period of time.
Conversion charts should be prepared and checked, and the new strength and volume of each dose should be communicated to providers and patients/families before any prescription conversion.
Eprontia doses should be prescribed in mg-based, not mL-based doses, and practitioners should clarify and discuss Eprontia doses based on the mg dose. Consider tagging prescriptions for Eprontia for mandatory patient education, especially if the patient was previously using a different concentration.
Educate patients and/or caregivers about the new concentration, the corresponding volumetric dose, and how to measure each dose with an oral syringe.
Nonspecific PRN medication administration
If a medication is ordered QID PRN, might a practitioner or patient interpret this to mean that all 4 allowable doses that day could each be given at any frequency interval—say, just one hour apart? What if oxycodone was ordered that way, or ibuprofen?
Technically, the answer is yes!
Practitioners or patients have interpreted QID PRN to mean that 4 doses a day (QID) could be given at any frequency interval (as needed [PRN]) as long as it is administered just 4 times a day. If you are servicing or practicing in a setting that utilizes an electronic health record (EHR) system, this means the EHR might allow these doses to be documented as such.
However, this may not be the prescriber’s intended meaning of the medication’s frequency and it may not be safe for patients, depending on the medication involved.
Frequencies such as BID PRN, TID PRN, and QID PRN do not provide clear directions regarding the interval between doses of a medication. They allow ambiguity that can foster practitioner-to-practitioner and patient-to-patient variability in interpretation and may result in harmful outcomes. Such errors have been reported to ISMP.
We recommend eliminating the use of nonspecific PRN frequencies in all care settings (e.g., inpatient, long-term care, other outpatient settings). Instead, the prescriber should specifically define the minimum time (e.g., hours) between PRN doses within the order.
Frequencies such as “every 8 hours PRN” or “every 12 hours PRN,” for example, provide specific directions regarding when medications can be administered by clearly defining the amount of elapsed time between doses. Prescribing and EHR systems should not allow nonspecific PRN frequencies as part of an order. Also, all PRN medication prescriptions should include the purpose for the drug and the specific dosing parameters.
Both prescribers and pharmacists also should provide patients with clear, specific directions both verbally and in writing. When counseling a patient about a medication, use the teach-back method to verify that they understand the information and will be able to use the drug correctly. ■