From the Guidelines
Atomoxetine typically takes 6-12 weeks to show full therapeutic effects in adults at a 40 mg dose, though some patients may notice initial improvements within a few weeks. The medication works by inhibiting norepinephrine reuptake in the brain, which gradually builds to therapeutic levels over time 1. Unlike stimulants that provide immediate effects, atomoxetine requires consistent daily dosing to reach steady-state plasma concentrations. Patients should be aware that the 40 mg dose may be adjusted based on response and tolerability, with the recommended target dose often being 80 mg daily or higher for adults (up to 100 mg) 2. Some key points to consider when prescribing atomoxetine include:
- Common side effects during the initial weeks include nausea, vomiting, fatigue, decreased appetite, abdominal pain, and somnolence 2
- Atomoxetine can be administered in the morning or evening, and the daily dose can be split into two equal doses if needed 1
- Regular follow-up with a healthcare provider is recommended to assess response and adjust dosing as needed, as premature discontinuation may prevent achieving optimal therapeutic effects
- Atomoxetine may be considered as a first-line treatment option in certain comorbidities, such as disruptive behavior disorders, tic disorder, Tourette's syndrome, and substance use disorders 1
From the Research
Time to Effect for Atomoxetine 40 mg in Adults
- The provided studies do not directly address the time to effect for atomoxetine 40 mg in adults.
- However, study 3 mentions that patients were randomized to receive either placebo or atomoxetine (60-100 mg) for 24 weeks, following a 2-week on-label (40 mg for 3 days then 80 mg) or slow (40 mg for 7 days then 80 mg) titration, and that Conners' Adult ADHD Rating Scale Total ADHD Symptoms score reduction was greater with atomoxetine over placebo at 12 weeks.
- Study 4 reports that improvements in ADHD symptoms were seen in adults with ADHD treated with atomoxetine (60, 90 or 120 mg/day) compared to placebo, but does not specify the time to effect for a 40 mg dose.
- Study 5 investigates the dosing patterns of atomoxetine monotherapy in adult patients with ADHD, but does not provide information on the time to effect for a specific dose.
- Study 6 compares the effects of pharmacological treatments for ADHD on haemodynamic values and electrocardiogram (ECG) parameters, but does not address the time to effect for atomoxetine 40 mg.
- Study 7 reviews the long-term efficacy and safety of treatment with stimulants and atomoxetine in adult ADHD, but does not provide specific information on the time to effect for a 40 mg dose of atomoxetine.