Shakiness from Strattera: What to Expect
Yes, shakiness (tremor) is a recognized adverse effect of Strattera (atomoxetine), and while it typically appears early in treatment, it can persist for weeks to months depending on individual factors.
Understanding the Side Effect
Tremor is listed among the common adverse effects of atomoxetine in clinical trials 1. According to FDA labeling data, tremor was specifically reported in overdose cases but is also documented as occurring during standard therapeutic use 2. The drug works by increasing norepinephrine levels in the brain, which can lead to sympathetic nervous system activation—manifesting as tremor, along with other effects like increased heart rate and blood pressure 1.
Timeline: When It Starts and How Long It Lasts
Onset: Common adverse events with atomoxetine, including tremor, typically appear within the first week of treatment 3. This early onset is consistent across most patients starting the medication.
Resolution: Based on research examining adverse event resolution times, the median time for common side effects to resolve ranges from 3 to 53 days 3. However, this data reflects resolution after discontinuation of atomoxetine. If you continue taking the medication, tremor may:
- Diminish as your body adjusts (typically within 2-8 weeks)
- Persist throughout treatment in some individuals
- Worsen with dose increases
What You Should Do
Immediate actions:
- Do not stop the medication abruptly without consulting your prescriber
- Monitor the severity—mild tremor that doesn't interfere with daily activities may be tolerable
- Note if the tremor worsens, becomes disabling, or is accompanied by other concerning symptoms (severe agitation, confusion, hallucinations)
Clinical management options:
- Dose adjustment: Splitting the daily dose into morning and evening administration can reduce adverse effects 1
- Timing modification: Taking atomoxetine in the evening only may help if tremor is most problematic during daytime activities 1
- Medication reassessment: If tremor is severe or persistent beyond 6-8 weeks, your prescriber may consider switching to an alternative ADHD medication
Important Caveats
Watch for these red flags that require immediate medical attention:
- Tremor accompanied by confusion, disorientation, or hallucinations (may indicate toxicity) 2
- Severe agitation or aggressive behavior 2
- Signs of sympathetic overdrive: severe rapid heartbeat, very high blood pressure, extreme restlessness 2
Drug interactions matter: If you're taking SSRIs (like fluoxetine, paroxetine) or other medications that affect CYP2D6, your atomoxetine levels may be elevated, increasing the risk and severity of tremor 1. Approximately 7% of people are "poor metabolizers" who naturally have higher drug levels and more side effects 1.
Context from Guidelines
Atomoxetine is considered a second-line ADHD medication with generally less frequent and less pronounced adverse effects compared to other non-stimulants like clonidine or guanfacine 1. The therapeutic effects take 6-12 weeks to fully develop 1, so side effects may appear before you experience the full benefit of the medication.
Bottom line: Tremor from Strattera is normal but shouldn't be ignored. Most patients see improvement within 3-8 weeks of continued treatment. If it's interfering with your quality of life or persists beyond 2 months, contact your prescriber to discuss dose adjustment or alternative treatments.