Qelbree Side Effects

Generic name: viloxazine

Medically reviewed by Philip Thornton, DipPharm. Last updated on Jan 27, 2025.

Note: This document provides detailed information about Qelbree Side Effects associated with viloxazine. Some dosage forms listed on this page may not apply specifically to the brand name Qelbree.

Applies to viloxazine: oral capsule extended release.

Precautions

It is very important that your doctor check your or your child's progress at regular visits to make sure this medicine is working properly and to decide if you should continue to take it. Blood tests may be needed to check for unwanted effects.

Do not take viloxazine (the active ingredient contained in Qelbree) with or within 14 days of taking a drug with monoamine oxidase (MAO) inhibitor activity (eg, isocarboxazid [Marplan®], phenelzine [Nardil®], procarbazine [Matulane®], selegiline [Eldepryl®], or tranylcypromine [Parnate®]). If you do, you may develop extremely high blood pressure.

Do not use this medicine if you are using alosetron (Lotronex®), duloxetine (Cymbalta®), ramelteon (Rozerem®), tasimelteon (Hetlioz®), theophylline (Theo-24®), or tizanidine (Zanaflex®).

Tell your doctor right away if you or your family notice any unusual changes in behavior, such as an increase in aggression, hostility, agitation, irritability, or suicidal thinking or behavior. Also tell your doctor if you or your child see, hear, or feel things that are not there, or have any unusual thoughts, especially if they are new or getting worse quickly.

You will also need to have your or your child's blood pressure and heart rate measured before starting this medicine and while you are using it. If you notice any change in your or your child's blood pressure, call your doctor right away. If you have questions about this, talk to your doctor.

This medicine may make you drowsy, sleepy, or tired. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines, and especially those for appetite control, asthma, colds, cough, hay fever, allergies, or sinus problems.

Serious side effects of Qelbree

Along with its needed effects, viloxazine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking viloxazine:

Other side effects of Qelbree

Some side effects of viloxazine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

For healthcare professionals

Applies to viloxazine: oral capsule extended release.

General adverse events

The most reported adverse reactions have included somnolence, decreased appetite, fatigue, nausea, vomiting, insomnia, and irritability. The adverse reactions most commonly associated with discontinuation were somnolence, nausea, headache, irritability, tachycardia, fatigue, and decreased appetite.^[Ref]

Nervous system

• Very common (10% or more): Somnolence (16%), headache (11%)

In short-term, placebo-controlled clinical trials, somnolence (including lethargy and sedation) was reported in 16% of treated patients compared to 4% of placebo patients.

Cardiovascular

• Very common (10% or more): Increase in heart rate (22%), increase in blood pressure (25%)

In patients 6 to 11 years (n=154), 22% of patients treated with this drug at 100 mg/day had a 20 beat per minute (bpm) or greater increase in heart rate at any time point in the clinical trial, compared to 9% of placebo patients (n=159). For the 200 mg dose, an increase in bpm was found in 31% (84/268) of patients receiving the drug compared to 15% (39/262) in the placebo group. These number were 28% (28/100) and 23% (24/103) for patients receiving 400 mg/day and placebo, respectively. For patients 12 to 17 years receiving 200 mg/day, 22% (22/99) had a 20 bpm increase in heart rate at any point in the clinical trial compared to 15/104 (14%) of patients who received placebo. For the 400 mg dose, the percentages were 34% (69/205) and 17% (35/201) in treated patients and placebo, respectively. For patients 12 to 17 years, 25% (52/205) of patients receiving 400 mg/day had a 15 mmHg or greater increase in diastolic blood pressure at any time in the clinical trial, compared to 13% (26/201) of patients in the placebo group.

Other

• Common (1% to 10%): Fatigue, pyrexia

Metabolic

• Common (1% to 10%): Decreased appetite
• Frequency not reported: Weight changes

In short-term, controlled studies (6 to 8 weeks), patients 6 to 11 years gained an average of 0.2 kg compared to a gain of 1 kg in same-aged patients who received placebo. For patients 12 to 17 years, an average of 0.2 kg was lost compared to a weight gain of 1.5 kg in same-aged patients who received placebo.

Respiratory

• Common (1% to 10%): Upper respiratory tract infection

Gastrointestinal

• Common (1% to 10%): Abdominal pain, nausea, vomiting

Psychiatric

• Common (1% to 10%): Insomnia, irritability
• Uncommon (0.1% to 1%): Suicidal ideation, behavior, or both

In short-term trials, a total of nine patients (0.9%) reported suicidal ideation (n=6), behavior (n=1) or both (n=2). Eight patients reported suicidal ideation or behavior on the Columbia Suicide Severity Rating Scale (C-SSRS), a validated scale that assesses suicide risk. An additional patient treated with this drug reported suicidal behavior during the clinical trials but did not report it on the C-SSRS. Among 463 patients treated with placebo in these studies, two patients (0.4%) reported suicidal ideation on the C-SSRS. No patients treated with placebo reported suicidal behavior. No completed suicides occurred in these trials.

See also:

Frequently asked questions

• Qelbree vs. Strattera: How do they compare?
• Qelbree vs Adderall: What's the difference between them?
• Should I take Qelbree morning or night?

Further information

Qelbree side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

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