Qelbree Side Effects: What to Know Before and During Treatment 

Qelbree is a nonstimulant medication for ADHD, and people commonly look up its side effects because they are considering treatment or have started taking it and noticed something unexpected. 

This guide covers what the prescribing information reports, which side effects are common, which are serious, and what should prompt a call to your prescriber. 

This article explains general information about a prescription medication. It does not contain dosing instructions and cannot replace the medication guide that comes with your prescription. Do not start, stop, or change the dose of Qelbree on your own. 

The boxed warning comes first

Qelbree carries an FDA boxed warning for suicidal thoughts and behaviors. In clinical trials, these were reported more often in patients treated with Qelbree than in patients treated with placebo. Anyone taking Qelbree should be monitored closely for clinical worsening and for the emergence of suicidal thoughts and behaviors, especially during the initial months of treatment and at times of dosage changes. 

A boxed warning is the strongest warning the FDA issues. It is worth understanding what the numbers behind it look like. According to the prescribing information, among 1,019 pediatric patients exposed to Qelbree in short-term trials, nine patients (0.9%) reported suicidal thoughts or behavior. No completed suicides occurred in these trials. 

Although the percentage was small, the finding is clinically important and is the reason for the FDA boxed warning. The prescribing information recommends close monitoring for clinical worsening and the emergence of suicidal thoughts and behaviors, particularly when treatment begins and when the dosage changes. 

Tell your prescriber promptly about new or worsening depression, anxiety, agitation, irritability, unusual changes in behavior, or any thoughts of suicide or self-harm. Family members and caregivers may notice changes that the person taking the medication does not notice, so it helps if someone close to you knows what to watch for. 

What Qelbree is, and is Qelbree a stimulant?

Qelbree is the brand name for viloxazine extended-release capsules. It is not a stimulant and is not a controlled substance, which distinguishes it from medications such as Adderall, Concerta, and Vyvanse. 

Qelbree is a selective norepinephrine reuptake inhibitor, although its mechanism of action in the treatment of ADHD is not fully understood. It is FDA-approved for ADHD in adults and pediatric patients ages 6 and older, and it is taken once daily. 

As a nonstimulant medication, Qelbree has a different adverse-effect profile from stimulant medications. 

Common side effects

The prescribing information defines the most common adverse reactions as those occurring in at least 5% of patients and at least twice the rate observed with placebo. 

• Somnolence, which can include sleepiness, sedation, or lethargy 
• Decreased appetite 
• Fatigue 
• Nausea 
• Vomiting 
• Trouble sleeping 
• Irritability 

In adults, the most common adverse reactions also include insomnia, headache, somnolence, fatigue, nausea, decreased appetite, dry mouth, and constipation. How long side effects last varies from person to person. If a side effect is persistent, severe, or interfering with daily activities, discuss it with your prescriber. 

Qelbree side effects in adults compared with children

The prescribing information reports different adverse-reaction patterns in pediatric and adult clinical trials. Information about Qelbree side effects often focuses on pediatric treatment, even though Qelbree is also approved for adults. 

Reported in clinical trials	Children ages 6 to 17	Adults
Somnolence	Reported in 16% of patients treated with Qelbree, compared with 4% on placebo	Reported in 6% of patients treated with Qelbree, compared with 2% on placebo
Fatigue	Reported in 6% of patients treated with Qelbree, compared with 2% on placebo	Reported in 12% of patients treated with Qelbree, compared with 3% on placebo

In the clinical trials, somnolence was reported in 16% of pediatric patients and 6% of adults, while fatigue was reported in 6% of pediatric patients and 12% of adults. Both can affect alertness. Do not drive or operate hazardous machinery until you know how Qelbree affects you. 

Serious warnings beyond the boxed warning

Increased heart rate and blood pressure 

Qelbree can increase heart rate and blood pressure. The prescribing information directs clinicians to assess both before starting treatment, after any dose increase, and periodically during treatment. Tell your prescriber about any cardiovascular condition or history of high blood pressure before starting treatment. 

Activation of mania or hypomania 

Qelbree may induce a manic or mixed episode in people with bipolar disorder. The prescribing information recommends screening patients for bipolar disorder and monitoring for manic or mixed episodes. It also calls for attention to personal or family history of suicide, bipolar disorder, depression, mania, or hypomania. This is one reason a complete psychiatric history is important before treatment. 

Somnolence and fatigue 

Somnolence and fatigue are specifically addressed in the prescribing information because they can affect alertness. Do not drive or operate hazardous machinery until you know how Qelbree affects you. 

Drug interactions that matter

Qelbree has several clinically important drug interactions that should be reviewed before treatment. 

Viloxazine is a strong CYP1A2 inhibitor. This can significantly increase exposure to certain medications that are metabolized by CYP1A2, which in turn raises the risk of side effects from those medications. 

Qelbree is contraindicated with sensitive CYP1A2 substrates and CYP1A2 substrates with a narrow therapeutic range. Examples of medications identified in the prescribing information include alosetron, duloxetine, ramelteon, tasimelteon, tizanidine, and theophylline. Qelbree is contraindicated with monoamine oxidase inhibitors and within 14 days after discontinuing an MAOI because of the risk of hypertensive crisis. 

Give your prescriber and pharmacist a complete list of everything you take, including over-the-counter medicines and supplements. This medication has clinically important drug interactions, so provide your prescriber and pharmacist with a complete list of everything you take. 

Qelbree, weight, and appetite

Decreased appetite is among the commonly reported side effects, and the prescribing information directs that patients be monitored for changes in weight during treatment. 

Weight gain is not listed among the common adverse reactions in the prescribing information. Weight changes can occur for different reasons, including changes in appetite or other factors. If your weight is changing in a way that concerns you, tell your prescriber rather than adjusting your eating or your medication on your own. Regular monitoring is part of routine treatment and can help identify clinically important changes. 

How long does Qelbree take to work?

Qelbree may require time for its effects to become clear, so prescribers generally assess response over time. 

Prescribers may adjust treatment based on response and tolerability. The time needed to assess response varies from person to person, and your prescriber can tell you when to follow up. Your prescriber can tell you what to expect and when to check in. Side effects and benefits do not always appear on the same timeline, which is worth knowing before you judge the medication too early. 

Qelbree compared with Strattera 

Both are nonstimulant ADHD medications, but they work differently. Qelbree affects norepinephrine signaling, while atomoxetine selectively inhibits norepinephrine reuptake. They are sometimes discussed together because both are nonstimulant ADHD medications. Strattera is the brand name for atomoxetine. 

They are different medications with different interaction profiles and different labelling, and neither medication is established as the best option for every patient. Both medications carry warnings about suicidal thoughts and behaviors, although their prescribing information and clinical evidence should be considered separately. If a prescriber has suggested one over the other, the reasoning usually involves your other medications, your medical history, and your previous experience with ADHD treatment. 

What to tell your prescriber before starting

• Any personal or family history of suicide attempts, bipolar disorder, or depression 
• Any cardiovascular condition, or a history of high blood pressure 
• Every medication you take, including over-the-counter medicines and supplements 
• Whether you are pregnant, planning a pregnancy, or breastfeeding 
• Any kidney condition or other significant medical condition 
• How you responded to previous ADHD medications, including side effects 

The prescribing information states that viloxazine may cause maternal harm based on animal reproduction studies. The prescribing information states that Qelbree should be discontinued when pregnancy is recognized unless the benefits of treatment outweigh the potential risk to the mother. Discuss this before starting rather than after. 

If you are breastfeeding or plan to breastfeed, discuss this with your prescriber. Viloxazine and its metabolite are present in human breast milk, and the prescribing information states that there are no data on effects in the breastfed infant or on milk production. 

When to seek care

If you are in the U.S. and have thoughts of suicide or self-harm, call or text 988 to reach the 988 Suicide & Crisis Lifeline, or go to the nearest emergency department. If you are in immediate danger, call 911. Seek emergency medical care for chest pain, severe agitation, confusion, a seizure, or other serious or rapidly worsening symptoms. 

Contact your prescriber promptly, rather than waiting for your next appointment, for new or worsening depression or anxiety, unusual agitation or irritability, or a racing heartbeat. The same applies to unusually elevated mood or energy, sleepiness that interferes with driving or work, or persistent nausea or vomiting. 

Frequently asked questions

Is Qelbree a controlled substance? 

No. Qelbree is not a stimulant and is not a controlled substance. 

Do Qelbree side effects go away? 

Some side effects may become less noticeable over time, while others may persist. If a side effect is severe, persistent, or interfering with daily activities, contact your prescriber. Report what you are experiencing rather than waiting it out indefinitely, because a prescriber has options. 

Can I drink alcohol while taking Qelbree? 

Alcohol can contribute to sleepiness or fatigue, which are also associated with Qelbree. Ask your prescriber or pharmacist about alcohol use while taking Qelbree. 

What happens if I miss a dose? 

Follow the instructions provided with your prescription or ask your pharmacist what to do. Do not take an extra dose unless your prescriber specifically tells you to. 

Can I stop Qelbree suddenly? 

Talk with your prescriber before stopping Qelbree so they can advise you based on your treatment plan and medical history. Do not stop treatment without discussing it with your prescriber. 

Is Qelbree safe for adults with ADHD? 

Qelbree is FDA-approved for adults as well as for children aged 6 and older. Whether Qelbree is appropriate for a particular person depends on their medical history, other medications, response to treatment, and appropriate monitoring. 

This information is for educational purposes and is not a substitute for individualized medical advice, diagnosis, or treatment. 

Talking with a prescriber about ADHD medication

Nonstimulant medications may be considered when stimulant medications are not effective, are not tolerated, or are not appropriate for a particular patient. That decision should take into account your medical history, other medications, symptoms, treatment response, and potential risks. PsychPlus provides ADHD evaluation and medication management through in-person visits and telehealth. 

If you are already taking Qelbree and something has changed, tell your prescriber what you noticed, when it started, and whether it followed a dose change. You can also learn more about the conditions our clinicians treat on our What We Treat page and read about how care works for patients. 

Whether you prefer virtual or in-person care, we are here to help. We can help you understand your symptoms and find the right support. Book an appointment to get started. 

Sources

• QELBREE (viloxazine extended-release capsules), prescribing information. Supernus Pharmaceuticals, Inc. DailyMed, U.S. National Library of Medicine. 

• QELBREE (viloxazine extended-release capsules), Prescribing Information. U.S. Food and Drug Administration. Revised January 2025. 

• Mental Health Medications. National Institute of Mental Health. 

• ADHD in Adults. Centers for Disease Control and Prevention, United States. 

• Attention deficit hyperactivity disorder: diagnosis and management. NICE guideline NG87. National Institute for Health and Care Excellence, United Kingdom. 

Medication labeling and warnings can change over time. PsychPlus reviews this article at least annually and updates it when relevant labeling, evidence, or clinical guidance changes.