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Viloxazine
Viloxazine is a morpholine-derived antidepressant1 used to treat attention deficit hyperactivity disorder (ADHD).2 It is classified as a non-stimulant medication3 and is described as a medication without evidence of drug dependence.3 It was approved for treating depression in adults in the UK in 1974, subsequently marketed there and in several European countries, and later repurposed for ADHD.4 It can increase heart rate and blood pressure,2 rarely cause suicidal thoughts or behaviors, and trigger mania or hypomania in people with bipolar disorder.
Dosage & Duration
Dosage
Doses are population estimates that vary widely between individuals.
Duration
Subjective Effects
Pharmacology
Pharmacodynamics
Viloxazine selectively inhibits the norepinephrine transporter, reducing norepinephrine reuptake and increasing its extracellular levels in several brain regions. It also enhances neuronal sensitivity to serotonin and increases brain serotonin levels; in vitro, it antagonizes 5-HT2B receptors and activates 5-HT2C receptors.5 Its 5-HT2B antagonism may promote serotonin release by reducing inhibitory control of serotonin neurons.5 Weak antagonism at 5-HT7, α1B-adrenergic, and β2-adrenergic receptors may also contribute to its action. Its overall mechanism remains incompletely understood, and evidence is insufficient to establish whether direct or indirect effects on dopamine contribute meaningfully.
Pharmacokinetics
Viloxazine is rapidly absorbed orally. The extended-release formulation has approximately 88% of the bioavailability of the immediate-release formulation,2 with peak concentrations and total exposure increasing proportionally over 100-600 mg once daily;2 reported peak concentrations range from 540 to 1,600 ng/mL. Metabolism primarily involves CYP2D6-mediated hydroxylation followed by glucuronidation through UGT1A9 and UGT2B15, and the parent drug can also undergo glucuronidation. Viloxazine inhibits CYP1A2, CYP2B6, CYP2D6, CYP3A4, and CYP3A5.2 After intravenous administration, viloxazine's volume of distribution was 0.73 ± 0.28 L/kg and clearance was 124 ± 11 mL/hour/kg.6 Elimination is mainly renal, with approximately 90% of a dose recovered in urine within 24 hours, less than 1% in feces, and approximately 12-15% eliminated unchanged. Immediate-release elimination half-life is reported as 2-5 hours, with 2-3 hours in the most reliable studies, while the extended-release mean is 7.02 ± 4.74 hours.
Caution
Use cautionThese combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.
Tolerance
Harm Potential
Addiction & Dependence
Psychological
Extremely LowViloxazine is not associated with abuse risk or known misuse liability.
Physical
Extremely LowViloxazine is described as lacking a risk of physical dependence.
Toxicity
Reported overdoses involved 1000–6500 mg, approximately 1.7–10.8 times the maximum recommended daily dose; these amounts are not established human lethal doses. Drowsiness was the most frequently reported symptom, with impaired consciousness, diminished reflexes, and increased heart rate also reported. There is no specific antidote.7
LD50 Data
| Species | Route | Value |
|---|---|---|
| Rat | Oral | 2000 mg/kg |
Viloxazine can increase heart rate and blood pressure;7 increased heart rate has also been reported in overdoses involving 1000–6500 mg.
Viloxazine overdoses involving 1000–6500 mg have produced drowsiness, impaired consciousness, and diminished reflexes.
Seizure Risk
Three seizure cases have been reported worldwide with viloxazine. Most animal studies and clinical trials that included people with epilepsy indicated anticonvulsant effects.
History & Culture
Discovery and antidepressant use
Viloxazine was discovered by scientists at Imperial Chemical Industries and was described in the scientific literature as early as 1972. It was first marketed as an antidepressant in Europe in 1974 and was not marketed in the United States at that time.…
Legality
By Country
United StatesPrescription only
United KingdomPrescription only
Article Status
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