The U.S. Food and Drug Administration (FDA) has approved an update for the label for viloxazine ER (Qelbree) to now include new lactation data for breastfeeding women with attention-deficit/hyperactivity disorder (ADHD). The update to Section 8.2 of the label is based on a study involving 15 healthy lactating women. The study evaluated the pharmacokinetics of viloxazine and its major metabolite, 5-hydroxy viloxazine glucuronide (5-HVLX-gluc), in breastmilk and plasma, and calculated potential infant exposure. The study participants received 600 mg of viloxazine on Days 1, 2, and 3 at the same time each morning. Breastmilk and plasma samples were measured pre-dose and for 24 hours post-dose on Day 3.
Results showed that the estimated daily infant dose of viloxazine was 0.085 mg/kg, and the estimated daily infant dose of 5-HVLX-gluc was 0.00595 mg/kg. The relative infant dose of viloxazine and 5-HVLX-gluc was approximately 1% and 0.07%, respectively, of the weight-normalized maternal daily dose (8.58 mg/kg) of viloxazine. Lactation specialists interpret a relative infant dose <10% as generally safe for breastfeeding.
Additionally, the label update includes new pharmacodynamic data in Section 12.2. The updated label describes viloxazine’s partial agonist activity at the serotonin 5-HT2C receptor and its inhibition of the norepinephrine transporter, reinforcing its multimodal pharmacodynamic profile. Overall, viloxazine’s mechanism of action and efficacy in treating ADHD are proposed to result from NET inhibition and its activity at serotonin receptors, including partial agonism at 5-HT2C receptors, a unique feature not found in other currently prescribed ADHD treatments.
Viloxazine ER (Figure 1) is approved for use in patients ages 6 years and older with ADHD.