The Right Drug at the Wrong Dose in 4 Out of 10 Americans

It’s a “deficit of information” we should correct, says FDA Commissioner Robert Califf. He is speaking about the gap in information about how to correctly dose drugs for people living with obesity. Karen Weintraub, reporting for USA Today, tells us this gap might mean that doctors are prescribing the right drug at the wrong dose for up to four out ten Americans.

A Dose That Would Not Work in a Time of Crisis

This problem affects real people. Weintraub spoke with Courtney Gilbert, who was suffering from depression and thoughts of suicide. For treatment, Gilbert received brexpiprazole (Rexulti) and told us, “I did not find Rexulti effective at all.”

Rexulti is a drug that requires different dosing in people with obesity in order to be effective. But it was independent researchers who discovered this only after the drug received approval. So the drug’s labeling does not reflect this information. Doctors have almost no way of knowing because the information hides away in a pharmacology journal where few clinicians will ever see it.

Weintraub describes the problem well:

“For her part, Gilbert said she naturally assumed because her medication had been prescribed by a doctor that it had been researched and dosed properly. Luckily, she got through her period of suicidal thinking without acting on it, but other people, given an ineffective dose, might not.”

Harvard’s Fatima Cody Stanford describes the problem more starkly:

“There are so many layers of badness that can happen here if it’s not tested well and doesn’t reach effective levels in people with obesity. This is a recipe for disaster in a condition that’s not well understood, even if it is well treated.”

Two Burning Questions

All this leaves us with two questions. When will FDA start making pharma at least take a look to assure they don’t leave a gap in dosing instructions for people with obesity?

More urgently, why doesn’t Otsuka (the maker of Rexulti) simply update the drug’s labeling to give doctors adequate information for using this drug safely in people with obesity?

Click here for Weintraub’s excellent reporting in USA Today and here for further perspective.

Courtney Gilbert, still image from research interview / ConscienHealth

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October 23, 2023