Equianalgesic dosing of opioids is a two sided coin.

On one hand, it offers the ability to change one opioid for another.

This can alleviate any unwanted side effects or maximize a route of administration (e.g. oral morphine equivalents to a duragesic transdermal patch).

However, improper technique in dose conversion may lead to a patient with more pain, or an unwanted incidence of overdose or respiratory distress. 

In a recent study in Drug Safety by Haffey et al, the authors evaluated the accuracy and reliability of opioid conversion apps.

The authors identified apps across six mobile app stores during the month of February 2012, using search terms including: opioid, morphine, medical calculator, and conversions. Twenty-six apps were identified meeting the search criteria, with three subsequently excluded. Of the 23 apps identified, only 5 (22%) had the involvement of a named practitioner in the development of the app. Additionally, only 11 (48%) referenced their opioid conversion methods from journals, guidelines, or textbooks.

The most key parts of the study dealt with comparing the dosing conversions of the apps against a standard 1 mg of oral morphine. Conversion was done against: codeine (PO), morphine (IV/IM/SC), Fentanyl (IV), Oxycodone (PO), and Hydromorphone (PO). When conversions were conducted on each app and then compared, it was found there were a range in differences.

Some examples include a range of codeine equivalency of 3.3-12 mg, oxycodone 0.5-1 mg. Several apps also converted between morphine and methadone, though they had a range of 0.05-0.67 mg. However, this was not quantified statistically and not all of the apps included were capable of performing all the previously mentioned conversions. 43% of the apps analyzed took into account cross tolerance with a dosing tool, while the remainder did not provide any tool and only some recommended to the user to take this into consideration.

This is a rather interesting study as it elicits some questions that need to be answered. First, what process should be instituted in the development of a point-of-care app tool? Should some body of literature be followed? It would have been interesting if the authors had compared the apps with medical involvement against those without, and then determined if the range of dose conversions was substantially different. This would at least have demonstrated the importance of medical involvement in clinical app design.

Second, can federal oversight be enough to determine an apps credibility or accuracy? It would appear that some level of peer-review may be required to vet the effectiveness of these apps. However, as in previous studies, the authors did not mention what apps they identified. This leaves the readers unsure of which to perhaps avoid. Finally, how often could the use of these dose converters lead to unseen medical adverse events? It would be interesting to review events of an app that was consulted that led to patient harm.

While the aim of the iMedicalApps team is to review mobile medical apps and report to readers our experiences and identify questionable apps, perhaps what is also needed is a source for users to report apps of questionable nature for others to consult, sort of similar to a MedWatch, we need an AppWatch.

Haffey F, Brady RR, Maxwell S. A comparison of the reliability of smartphone apps for opioid conversion. Drug Saf. 2013;36(2):111-7.