Atomoxetine Can Cause Heart Pounding (Tachycardia)
Yes, atomoxetine can cause heart pounding (tachycardia) as it increases norepinephrine levels, which can affect cardiovascular function. 1 This is a recognized cardiovascular side effect that requires monitoring during treatment.
Mechanism of Action and Cardiovascular Effects
Atomoxetine is a selective norepinephrine reuptake inhibitor that:
- Increases synaptic noradrenaline by binding to the norepinephrine transporter 2
- Increases both noradrenaline and dopamine in the prefrontal cortex 2
- Can lead to cardiovascular effects due to its noradrenergic activity 3
Clinical Evidence of Cardiovascular Effects
The FDA drug label specifically mentions cardiovascular effects:
- Tachycardia was identified in 0.3% of pediatric patients and 1.5% of adult patients taking atomoxetine compared to 0% and 0.5% of placebo patients, respectively 1
- Palpitations occurred significantly more frequently in adult patients taking atomoxetine (3.7%) compared to placebo (0.8%) 1
- Mean heart rate increases of 5 beats/minute in extensive metabolizers (EM) and 9.4 beats/minute in poor metabolizers (PM) have been observed 1
Risk Factors for Increased Heart Rate Effects
Certain patient factors increase the risk of experiencing heart pounding:
- Poor metabolizers of CYP2D6 (approximately 7% of the population) experience significantly higher heart rate increases (11 beats/minute vs 7.5 beats/minute in extensive metabolizers) 1
- Patients with pre-existing cardiovascular conditions 1
- Patients with autonomic nervous system dysfunction, particularly central autonomic failure 4
Monitoring Recommendations
Guidelines recommend:
- Baseline blood pressure and heart rate measurement before initiating therapy 5
- Regular monitoring of pulse and blood pressure following dose increases and periodically during treatment 1
- Watching for significant increases in blood pressure (>140/90 mmHg), headache, chest pain, palpitations, and signs of cardiovascular distress 5
Clinical Implications
The cardiovascular effects of atomoxetine:
- Typically occur early in therapy and tend to stabilize over time 3
- Usually return toward baseline upon drug discontinuation 3
- Are generally considered small and of limited clinical significance in most patients 3
- May require dose adjustment or discontinuation if symptoms are severe or persistent 1
Cautions and Contraindications
Atomoxetine should be used with caution in:
- Patients with underlying medical conditions that could be worsened by increases in blood pressure or heart rate 1
- Patients with hypertension, tachycardia, or cardiovascular disease 1
- Patients with severe cardiac or vascular disorders (contraindicated) 1
Management of Cardiovascular Side Effects
If heart pounding or other cardiovascular symptoms occur:
- Consider dose reduction
- Monitor more frequently
- Evaluate for other causes
- If symptoms are severe or persistent, consider switching to an alternative medication 5
In most cases, the cardiovascular effects of atomoxetine are mild and manageable with appropriate monitoring. However, patients should be informed about this potential side effect and advised to report any concerning symptoms promptly.