Part VII – Interpreting PDMP Visualizations
BY JIM HUIZENGA, M.D. AND CHIEF CLINICAL OFFICER OF APPRISS HEALTH
Series Introduction – Appriss Health has long held that chronic pain and addiction (substance use disorder) are separate medical conditions and that each deserve a unique clinical approach. We have spent years developing clinical decision support tools and in doing so have obtained the feedback from countless medical professionals, including many pain providers. Through those providers we have also heard (directly and indirectly) from many chronic pain patients as well.
To continue this conversation, over a long series of blog posts, we will explore our approach to benefit/risk assessment, data presentation, and clinical support…and how they relate to our goal of creating a usable and balanced, clinical viewpoint that protects access to care while highlighting areas of risk that clinicians and patients should be aware of.
Details really matter.
I finished our last post with a comment that I saw something concerning in the example PDMP report, and it wasn’t just the number of providers the patient had seen. In fact, the patient’s recent use of multiple overlapping providers is something that deserves further evaluation. In Blog V I explained the multiple provider episodes (MPEs) metric is intended to identify patients at risk because they may have obtained more medication than is appropriate, for any number of reasons. While this isn’t always the case, I believe the details in this PDMP report indicate this is one of those times.
Let’s look at the graph again and reconstruct the timeline of care for this patient to explain why:
- The patient has been getting 150 hydrocodone/acetaminophen tablets regularly from Dr. Garcia. Here’s the first important detail that matters: The strength is noted as 10-325 and what that means is each pill has 10mg of hydrocodone and 325mg of acetaminophen. The prescription is for 25 days so that means the patient is supposed to be taking 6 pills per day.
- The patient was prescribed 90 clonazepam tablets, 1mg each, for 30 days…or 3 pills per day. This would be considered a relatively dangerous overlap of medication as opioids and sedatives (especially benzodiazepines) shouldn’t be co-prescribed, especially at higher doses.
- On 7/22 the patient saw Dr. Fields for the first time and received a 20 day prescription for tramadol. Tramadol is an opioid type of medication and adding it to hydrocodone/acetaminophen isn’t a bad choice if the patient needed some extra pain control, as tramadol tends to have less respiratory depression, so I can see why Dr. Fields might have prescribed it.
- On 8/6 the patient saw Dr. Webb and received 80 additional hydrocodone tablets at the same strength as her usual dose, prescribed for 6 days. That equates to 13-14 pills per day. Importantly, the patient hadn’t yet run out of the tramadol that was prescribed so at this time there are three active opioid prescriptions and an active sedative prescription.
Let’s pause here a minute…isn’t that a potential problem?
But perhaps for some reasons you may not immediately be aware of. I see something of concern in this scenario that has clinical risk beyond what you may be thinking or assume…
As we learned earlier, patients who take chronic opioids may become dependent on them and also tolerate them over time so it’s possible that a higher dose may be required at some point. Perhaps this is one of those times when the patient’s pain required a higher dose. Perhaps.
However, one of the “bigger problems” here is in the hidden risk of acetaminophen toxicity.
Let’s count things up.
Taken as prescribed on 8/6 – the patient would have taken:
- 6 hydrocodone/acetaminophen 10-325 tablets
- 4 tramadol tablets
- 3 clonazepam tablets
- 13 or 14 hydrocodone/acetaminophen 10-325 tablets
That’s 19 (or 20) doses of 325mg of acetaminophen in a single day. The maximum recommended daily dose of acetaminophen is 3,000mg per day. This patient is being prescribed 6,500mg per day. More than twice the recommended daily limit, and that could be a big problem.
Because acetaminophen in larger doses is toxic to the liver and hundreds of people per year die from an acetaminophen overdose.
Again, details matter…
In medical school I learned that 140mg/kg of acetaminophen is a toxic dose and I’ve taken care of some petite patients who have weighed around 100lbs and got shockingly close to a lethal overdose taking just 12 extra strength (500mg) acetaminophen tablets.
Here’s the math:
- 100lbs* 1kg/2.2lbs x 140mg/kg = 6,363mg (lethal dose).
- 12 extra strength tablets x 500mg/tablet = 6,000mg.
If this PDMP report belongs to one of those petite patients, then 6,500mg could be a lethal dose depending on how it was taken.*
Looking at this report, I have to surmise that Dr. Webb either (1) didn’t know the patient was already taking the same medication from another provider OR… Perhaps (2), the patient no longer had the prescription from Dr. Garcia and Dr. Webb was replacing the medication (perhaps the patient’s medications were lost or stolen?). Regardless of the actual reason, it would have been highly inappropriate for Dr. Webb to knowingly prescribe 14 more pills on top of the 6 pills the patient was already taking.
What do I do in a situation like this (and I’ve been here many times with my emergency department patients)? Simple, talk to the patient and find out what’s been going on, and make sure to discuss the potential for liver damage with high doses of acetaminophen. Sometimes there are legitimate (and safe) explanations…and sometimes the patient is engaging in dangerous self-medication. Details matter.
I’ll wrap up with one last detail about the prescription graph. You may have noticed that the graph doesn’t appear to have doses and you may be thinking that a provider needs to do some mental gymnastics to find out exactly what medicines were being prescribed when and by whom but that isn’t the case. Our graph is interactive and clicking (or dragging on it) shows all of the necessary prescription detail all in one place.
*Acetaminophen toxicity of 140mg/kg is most relevant when taken as a single large dose. In this particular example, I’m extending the risk into a 24-hour dosing period to make the point that sometimes there are real, but unexpected risks, buried in the prescription detail.
In the next post we’re going to begin discussing the benefits of scoring the PDMP data in an objective and intuitive manner, with the goal of raising provider awareness when risk is relatively high, and reassuring providers when risk is relatively low. This is a series about chronic pain and substance use disorder (addiction) and how they are different. As we will see, chronic pain patients generally have lower scores because they generally have lower risk. Conversely, patients with PDMP risk factors associated with substance use disorder generally have higher scores because… you guessed it… they have a higher risk of bad things happening (overdose, addiction, death, etc.).
Thank you. Again, these details really matter.
To read more on this series:
- Part I – Benefit and Risk
- Part II – Risk Defined
- Part III – Dependence and Addiction
- Part IV – PDMPs
- Part V – Multiple Provider Episodes
- Part VI – PDMP Visualization
- Part VII – Interpreting PDMP Visualizations
- Part VIII – Scoring PDMP Data
- Part IX – Understanding How PDMP Data is Scored
- Part X – Machine Learning
- Part XI – Epilogue