The FDA has approved an updated label for viloxazine extended-release capsules (Qelbree; Supernus Pharmaceuticals Inc.) to include new pharmacodynamic data and information regarding lactation, enhancing the understanding and use of the drug in treating attention-deficit/hyperactivity disorder (ADHD). Viloxazine is approved for patients aged 6 years and older.
Pharmacodynamic Insights
The updated label incorporates data highlighting viloxazine's interaction with key neurotransmitter systems. According to Stephen M. Stahl, MD, PhD, DSc (Hon), from the University of California Riverside, the new data "deepens our understanding of Qelbree, providing valuable insights to help support treatment decision-making for people living with ADHD." Specifically, viloxazine binds to and inhibits the norepinephrine transporter (Ki = 0.13 μM) and exhibits partial agonist activity at the serotonin 5-HT2C receptor (Ki = 0.66 μM). The precise mechanism of action, however, remains under investigation.
Lactation Data
The updated label also includes new data on lactation, indicating a low transfer of viloxazine into breast milk. A study involving 15 healthy, lactating women found that the estimated infant dose of viloxazine and its metabolite, 5-HVLX-gluc, were 0.085 mg/kg and 0.00595 mg/kg, respectively. This translates to approximately 1% and 0.07% of the maternal daily dose, respectively, when considering an infant body weight of 6 kg. The label advises considering the developmental and health benefits of breastfeeding alongside the mother's clinical need for viloxazine and any potential adverse effects on the breastfed infant.
Clinical Efficacy
The efficacy of viloxazine in pediatric patients was demonstrated in three short-term studies (NCT03247530; NCT03247543; NCT03247517), while its efficacy in adult patients was shown in one study (NCT04016779). Pediatric studies revealed statistically significant improvements in ADHD Rating Scale scores for patients treated with viloxazine compared to placebo. Similarly, the adult patient study showed a statistically greater change from baseline in the ADHD Investigator Symptom Rating Scale for those treated with viloxazine versus placebo. Furthermore, the clinical global impression-severity of illness score was also statistically greater for adults treated with viloxazine compared to placebo.
