— 7 deaths and over 100 serious adverse events reported to FDA after treatment with Vykat XR
August 12, 2026
• 2 min read
Prader-Willi syndrome experts are warning of potential safety risks associated with extended-release diazoxide choline (Vykat XR), a drug approved last year for treating the extreme bouts of hunger experienced by patients with the rare genetic condition.
As of July 31, seven deaths and more than 100 serious adverse events have been reported to the FDA’s Adverse Event Monitoring System, according to a statement released Tuesday from the Foundation for Prader-Willi Research, International Prader-Willi Syndrome Organization, and Prader-Willi Syndrome USA.
Most reports involved edema, respiratory problems, and cardiac complications. Severe or fatal cases typically involved complex health conditions, multiple prescriptions, and pre-existing obesity.
“The intention of this statement is to increase awareness of the risks for people with Prader-Willi syndrome when starting diazoxide choline/Vykat XR,” the groups stated.
Beyond the drug’s standard prescribing guidelines, the groups advised that clinicians conduct individualized baseline assessments, monitor patients closely, and consider slowing the dose titration process. The groups recommended additional safety evaluations, such as echocardiograms or fluid retention assessments, before and during treatment, particularly during dose increases.
Prescribers were also urged to watch for warning signs, including worsening edema, orthopnea, dyspnea, and unexpected weight gain.
Approved in March 2025, extended-release diazoxide choline was the first drug indicated for hyperphagia — the hallmark feature of Prader-Willi syndrome characterized by an intense, persistent sensation of hunger — in affected patients 4 years and older.
Drugmaker Neurocrine Biosciences told MedPage Today that diazoxide choline “has a compelling risk-benefit profile in the context of a very serious disease. Neurocrine conducted extensive diligence on the safety profile, including adverse event data.”
Edema was among the most common adverse events reported in clinical trials, occurring in at least 10% of participants and at a rate at least 2% higher than with placebo. The drug’s label warns of the risk of fluid overload.
The company added that it is “closely engaged with the FDA, patient advocacy communities, and prescribers to continue to assess all available data from postmarketing surveillance as the prescribing population expands.”
Tuesday’s statement emphasized that adverse event reports do not establish direct cause and effect, nor do they account for other medications patients were taking that may have contributed to severe outcomes or death.
Medical complications are inherently common in Prader-Willi syndrome, which is the most common genetic cause of life-threatening childhood obesity. Compared with the general population, mortality is higher across all age groups, with an annual mortality rate of 1% to 3%. Developmental delays and behavioral and emotional regulation difficulties are also common features.
Clinicians are urged to familiarize themselves with the complexities of managing Prader-Willi syndrome before prescribing the drug. Individuals with the condition often do not report pain or discomfort in standard ways, the expert statement advised. “If the prescriber is not highly experienced in caring for individuals with Prader-Willi syndrome, they may wish to consult with a more experienced provider prior to starting therapy.”
