Qelbree Side Effects: Sleep, Appetite, and Blood Pressure

Your prescriber suggested Qelbree because you want ADHD treatment without a stimulant. Then you read the label and hit a black box about suicidal thoughts. That’s a jarring thing to see on a medication meant to help you focus, and it deserves a clear explanation with the actual numbers.

According to a 2026 viloxazine review, viloxazine, the drug in Qelbree, blocks the reuptake of norepinephrine, a chemical messenger tied to attention, and also acts on serotonin receptors. It was first sold in Europe as an antidepressant in the 1970s. That targeted precision lets it treat ADHD without being a stimulant, and its side effects tend to involve your sleep, your appetite, and your heart rate.

The long-standing non-stimulant that works on the same transporter is atomoxetine (Strattera). The Strattera prescribing information carries a boxed warning for suicidal thoughts in children and teens, and it calls for the same kind of monitoring Qelbree’s label does: blood pressure and pulse checks, bipolar screening, and close observation early on. The same review found Qelbree’s effect sizes smaller than those of stimulants but comparable to atomoxetine’s. The results are real, and the science is well established.

But a boxed warning read without its numbers can scare people away from a reasonable option, and at Siggy we’d rather walk you through the data than leave you with a headline. This guide breaks down Qelbree’s side effects by age, explains exactly what the boxed warning found, and covers heart rate, appetite, and the interactions that raise risk. How often each side effect happens, and what you can do about it, is a question best answered by the clinical evidence.

What This Page Covers

• What Are the Most Common Qelbree Side Effects?
• Why Kids Get Sleepy and Adults Lie Awake
• The Qelbree Boxed Warning, Explained
• Does Qelbree Raise Heart Rate and Blood Pressure?
• Does Qelbree Affect Appetite or Weight?
• Who Should Use Qelbree Cautiously?
• How Long Do Qelbree Side Effects Last?
• When to Call Your Prescriber or 911

What Are the Most Common Qelbree Side Effects?

Qelbree is FDA-approved for ADHD in adults and children 6 and older, and its side effect pattern shifts with age. The rates below come from the short-term, placebo-controlled trials pooled in Qelbree’s prescribing information, shown as Qelbree versus placebo.

Side Effect	Ages 6 to 17	Adults
Sleepiness	16% vs 4%	6% vs 2%
Insomnia	4% vs 1%	23% vs 7%
Headache	11% vs 7%	17% vs 7%
Fatigue	6% vs 2%	12% vs 3%
Decreased appetite	7% vs 0.4%	10% vs 3%
Nausea	5% vs 3%	12% vs 3%
Irritability	3% vs 1%	4% vs 3%

Adults also reported dry mouth (10% versus 2%) and constipation (6% versus 1%). About 3% of children and teens and about 9% of adults stopped Qelbree because of a side effect. Label rates from separate trials can’t be compared directly with another drug’s, so use our Qelbree vs Strattera comparison for a side-by-side view.

Why Kids Get Sleepy and Adults Lie Awake

In children and teens, sleepiness rose with dose: 12% at 100 mg, 16% at 200 mg, and 19% at 400 mg. Adults flipped that pattern, with insomnia as their most common side effect. A phase 3 trial randomized 374 adults, and the average final dose was 504 mg a day.

What else you take matters too. In a phase 4 study of 56 children and teens who added Qelbree to a stimulant, sleepiness was nearly absent (1.8%), while insomnia reached 8.9%. Taking Qelbree in the morning or the evening didn’t appear to affect safety, response, or sleep improvement in that study, though it was small and open-label.

The label advises against driving or using heavy machinery until you know how Qelbree affects you. If sleep problems linger, our guide to ADHD sleep problems covers what else might be going on.

The Qelbree Boxed Warning, Explained

A boxed warning is the FDA’s strongest label warning. Here’s what Qelbree’s is based on:

• Children and teens: 9 of 1,019 on Qelbree (0.9%) reported suicidal thoughts, behavior, or both, versus 2 of 463 on placebo (0.4%).
• Adults: 3 of 189 on Qelbree (1.6%) reported suicidal thoughts, versus 0 of 183 on placebo.
• Outcomes: no completed suicides occurred, and no adults attempted suicide.

Atomoxetine’s boxed warning applies only to children and teens, and its label notes that a similar analysis in adults didn’t show increased risk. Qelbree’s covers adults too, based on those three adults in one trial.

The label flags insomnia, irritability, anxiety, agitation, panic attacks, and impulsive behavior as possible early warning signs. Monitoring matters most during the first few months and after any dose change, up or down. Real-world reports point the same way: a 2025 FAERS analysis of 546 viloxazine reports to the FDA found suicidal ideation among the most common reported events, with most events occurring within 30 days of starting. Voluntary reports can’t prove the drug caused them, but they reinforce why early check-ins matter.

Does Qelbree Raise Heart Rate and Blood Pressure?

Qelbree can raise both for some people. In the adult trial, 29% on Qelbree had a heart rate increase of 20 beats per minute or more at some point, versus 13% on placebo, and 13% had a diastolic rise of 15 mmHg or more, versus 9%. Among teens on 400 mg, 34% had that heart rate jump, versus 17% on placebo, and 25% had the diastolic rise, versus 13%.

This isn’t unique to Qelbree. A 2025 network meta-analysis notes that stimulants, atomoxetine, and viloxazine all have noradrenergic effects, and it advises monitoring blood pressure and pulse with any ADHD medication, not just stimulants. The label calls for checks before starting, after dose increases, and periodically during treatment.

Does Qelbree Affect Appetite or Weight?

Decreased appetite affected 7% of children and teens and 10% of adults. In 6- to 8-week trials, children ages 6 to 11 on Qelbree gained an average of 0.2 kg, versus 1 kg on placebo, and teens lost 0.2 kg, versus a 1.5 kg gain on placebo.

Over 12 months in an extension study, the average weight-for-age score dipped slightly, but there was no placebo group for comparison. The label recommends tracking weight during treatment, especially in kids.

Who Should Use Qelbree Cautiously?

Qelbree is a strong inhibitor of CYP1A2, a liver enzyme that clears several other drugs. Its Medication Guide says not to take it with alosetron, duloxetine, ramelteon, tasimelteon, tizanidine, or theophylline. It’s also off-limits with MAOI antidepressants, or within 14 days of stopping one, because of the risk of a dangerous blood pressure spike.

Other cautions from the label:

• Bipolar disorder: noradrenergic drugs like Qelbree may trigger a manic or mixed episode, so prescribers should screen first.
• Blood pressure or heart rate problems: tell your prescriber before starting.
• Pregnancy: the label says Qelbree may cause maternal harm, based on animal studies.
• Severe kidney disease: a lower dose is recommended.

How Long Do Qelbree Side Effects Last?

Qelbree reaches steady levels after about two days of daily dosing, and its half-life is about 7 hours. In a long-term extension trial of 1,100 children and teens with a median of 260 days on treatment, side effects were mostly mild or moderate. Sleepiness was reported by 9.5%, decreased appetite by 6.0%, and fatigue by 5.7%, and 8.2% stopped because of a side effect.

That’s lower than the 16% sleepiness rate in short-term trials, though the studies weren’t designed to compare directly. If a side effect isn’t easing after the first few weeks, tell your prescriber rather than stopping on your own.

When to Call Your Prescriber or 911

Call 911 if you or your child is in immediate danger of self-harm, or has chest pain, fainting, or a racing heartbeat that won’t settle. Call or text 988 for thoughts of self-harm or suicide. Contact your prescriber promptly for:

• New or worsening depression, anxiety, panic attacks, or irritability
• Trouble sleeping, agitation, or unusual restlessness
• Extreme energy, racing thoughts, or reckless behavior
• Blood pressure or pulse readings higher than usual

With Qelbree, the first few months are exactly when check-ins matter most, for mood, sleep, appetite, and blood pressure alike.

Qelbree’s side effects are real, but most people in its trials didn’t stop because of them. Sleep changes, lower appetite, and a faster pulse top the list, and the boxed warning calls for close attention early on rather than fear. Knowing the numbers helps you and your prescriber spot problems early. If you’re still weighing non-stimulant options, our guide to non-stimulant ADHD medications compares Qelbree with Strattera and Wellbutrin.

Ready to take control of your mental health? Start your anonymous intake with Siggy and get your plan reviewed by a licensed prescriber.

This article is for education only and isn’t a substitute for personal medical advice. Don’t start, change, or stop a medication without talking to your prescriber, except in an emergency described here. It was reviewed for clinical accuracy and reflects sources available as of September 2026.