Weight Loss with Qelbree (Viloxazine ER)
Qelbree is associated with modest weight loss in adolescents (average 0.2 kg loss over 6-8 weeks) and minimal weight changes in children (average 0.2 kg gain over 6-8 weeks), which is significantly less than the weight gain seen with placebo (1.0-1.5 kg gain). 1
Short-Term Weight Effects (6-8 Weeks)
The FDA-approved labeling provides the most definitive data on weight changes with Qelbree:
- Children (6-11 years): Qelbree-treated patients gained an average of 0.2 kg, compared to a 1.0 kg gain in placebo-treated patients 1
- Adolescents (12-17 years): Qelbree-treated patients lost an average of 0.2 kg, compared to a 1.5 kg gain in placebo-treated patients 1
This represents a relative difference of approximately 0.8 kg less weight gain in children and 1.7 kg difference (favoring weight loss) in adolescents compared to placebo over the short-term treatment period 1.
Long-Term Weight Effects (12 Months)
In the long-term open-label extension trial with 1,100 pediatric patients:
- Among 338 patients evaluated at 12 months, the mean change from baseline in weight-for-age z-score was -0.2 (standard deviation of 0.5) 1
- The FDA label notes that "in the absence of a control group, it is unclear whether the weight change observed in the long-term open-label extension was attributable to the effect of Qelbree" 1
- The long-term trial showed median exposure of 260 days, with decreased appetite reported in 6.0% of participants 2
Adult Weight Data
For adults, specific weight loss data from clinical trials is not provided in the available evidence. The FDA label for adults lists "decreased appetite" as occurring in 10% of patients (compared to 3% with placebo), but quantitative weight change data is not reported 1.
Clinical Context and Comparison
Qelbree's weight effects are minimal compared to FDA-approved obesity medications, which typically produce 5-10% total body weight loss 3. For context:
- Semaglutide 2.4 mg produces 10.76% more weight loss 3
- Phentermine produces approximately 6.0 kg weight loss at 28 weeks 3
- Liraglutide 3.0 mg is approved specifically for weight management 3
Important Caveats
Qelbree is not indicated or approved for weight loss - it is an ADHD medication where weight changes are monitored as a safety parameter 1, 4. The weight effects observed are:
- Modest in magnitude (less than 0.5 kg difference from baseline in most patients) 1
- Variable by age group (minimal gain in children vs. minimal loss in adolescents) 1
- Confounded by natural growth patterns in pediatric populations, making interpretation challenging 1
- Not systematically studied as a primary outcome in clinical trials 5, 6, 4
The most common adverse effect related to weight is decreased appetite, occurring in 8% of pediatric patients (vs. 0.4% with placebo) and 10% of adults (vs. 3% with placebo) 1. This appetite suppression appears to be the mechanism for any weight effects observed 4.