Is 600mg of Qelbree a High Dose?
Yes, 600mg is the maximum approved daily dose of Qelbree (viloxazine extended-release) for adults and represents the upper limit of the therapeutic range. 1
FDA-Approved Dosing Parameters
For adults (18-65 years):
- Starting dose: 200 mg once daily 2
- Titration: Increase by 200 mg increments at weekly intervals 2
- Maximum dose: 600 mg/day 2, 1
For adolescents (12-17 years):
- Maximum dose: 600 mg/day 3
For children (6-11 years):
- Maximum dose: 400 mg/day 3
Clinical Context from Trials
In the pivotal adult phase III trial, the mean dose at end of study was 504 mg, indicating most patients required doses below the 600 mg maximum 4. However, in the long-term extension study, 73% of adult participants used doses ≥400 mg/day during maintenance treatment, with 36% using the full 600 mg/day dose 5. This demonstrates that while 600 mg is the maximum, it is commonly needed for optimal therapeutic effect in a substantial proportion of adult patients.
In the pediatric long-term study, the median modal doses were 300 mg/day for children and 400 mg/day for adolescents, suggesting most younger patients achieve benefit at lower doses than the maximum 3.
Safety Profile at Maximum Dose
The most common adverse events in adults receiving flexible doses of 200-600 mg included insomnia (14.8%), fatigue (11.6%), nausea (10.1%), decreased appetite (10.1%), dry mouth (9.0%), and headache (9.0%) 4. The discontinuation rate due to adverse events was 9.0% in the viloxazine group versus 4.9% in placebo 4.
Important safety considerations at 600 mg:
- Monitor for cardiovascular effects including increased blood pressure and pulse 2
- Watch for suicidal thinking and behavior, particularly in patients through age 24 2
- Be vigilant for serotonin syndrome risk, especially when combined with other serotonergic agents 2, 6
- Common gastrointestinal symptoms (nausea, vomiting, abdominal discomfort) may be dose-related 2
Clinical Decision-Making
600 mg should be used when:
- Lower doses (200-400 mg) have been inadequate for symptom control 2
- The patient has tolerated dose escalation without significant adverse effects 1
- Weekly titration has been followed to assess response at each dose level 2
Avoid or use extreme caution with 600 mg when:
- Patient is taking MAOIs or within 2 weeks of MAOI discontinuation (contraindicated) 1
- Concurrent use of sensitive CYP1A2 substrates or those with narrow therapeutic range (contraindicated) 1
- Patient is taking other serotonergic agents (increased serotonin syndrome risk) 2, 6
- Significant adverse effects emerged at lower doses 1