How Purdue Used Misleading Charts to Hide OxyContin's Addictive Power

A case filed by the Commonwealth of Kentucky against Purdue Pharma sheds new light on the origin of an infamously misleading chart showing that OxyContin stays in patients' blood levels over time, when in fact levels of the drug drop off sharply in users, triggering withdrawal symptoms and addiction. The chart was later used by Purdue as a marketing tool to convince doctors that OxyContin was less addictive than it actually was, the case claims.
The suit is unusual because Kentucky isn't just seeking reimbursement for Medicaid payments it made based on misleading marketing for the drug. It's seeking all costs it incurred associated with OxyContin abuse, including millions spent in drug abuse education and prevention, and the "investigation, apprehension, prosecution and incarceration of individuals, who, due to the fraudulently concealed addictive nature of OxyContin, have resorted to criminal means to continue their addiction." Forty people in Pike County, Ky., have died from OxyContin abuse, the case claims. Damages could potentially reach into the billions of dollars.

A version of the chart surfaced in a petition demanding the FDA remove the chart from OxyContin's official labeling. The chart appears to show that OxyContin doses peak quickly and then plateau in the blood stream, providing constant levels of pain relief (click to enlarge images):

But the chart is in logarithmic scale, not linear scale. In a log scale, each point on the vertical axis is a multiple of the point below it. On a linear scale -- the scale most people are accustomed to seeing in charts -- the points represent equal intervals. The same data on a linear scale looks like this, showing that OxyContin doses peak quickly and then fall off after a few hours:

The Kentucky case claims that Purdue first developed the chart in a study in the mid 1990s. The chart compared a controlled-release version of the drug taken every 12 hours with an immediate release version taken every six hours. The CR version featured fewer "peaks and valleys," Purdue claimed, and the study represented the levels on a linear scale:

In 1995, however, Purdue applied to the FDA to use the same data for the controlled release version in its marketing materials for doctors, but on a log-scale chart:

The log scale flattened the curve in the graph, and it carried the caption: "Fewer 'peaks and valleys' than with immediate-release oxycodone." After reviewing it, the FDA told the company on Dec. 20, 1995:

If [Purdue ] wishes to compare blood levels in the text, then DDMAC suggests that the blood levels for both dosage forms be presented in the graphic so that the reader can accurately interpret this claim.
Purdue withdrew the chart from the promotional materials, but the log scale chart remains in OxyContin's official labeling -- you can see it on page 6 of this document.

Purdue opposes the case. The Kentucky attorney general successfully petitioned to transfer the complaint from a New York federal court to Kentucky state court on Sept. 26.