Skipped Beats After Discontinuing SNRI
If you experience skipped beats (palpitations) after discontinuing an SNRI, this is likely part of SNRI discontinuation syndrome, which requires immediate medical evaluation to rule out cardiac complications, followed by consideration of restarting the medication with a slower taper. 1
Understanding SNRI Discontinuation Syndrome
SNRI discontinuation syndrome is a well-recognized phenomenon that occurs when these medications are stopped abruptly or tapered too quickly. 1 The syndrome includes:
- Autonomic symptoms: Increased blood pressure, increased pulse, tachycardia, diaphoresis (sweating), shivering 1
- Cardiovascular symptoms: Palpitations (skipped beats), arrhythmias 1
- Physical symptoms: Dizziness, headache, nausea, vomiting, diarrhea, fatigue, lethargy, myalgias 1
- Neurological symptoms: Sensory disturbances, paresthesias (electric shock sensations), tremor, imbalance, vertigo 1
- Psychological symptoms: Anxiety, irritability, agitation, insomnia, confusion 1
Symptoms typically emerge within a few days of discontinuation and can last several weeks, though late onset and longer persistence can occur. 2, 3
Immediate Clinical Action Required
You need urgent medical evaluation to distinguish discontinuation syndrome from potentially serious cardiac arrhythmias. 1 Your clinician should:
- Obtain an ECG to evaluate for actual arrhythmias, QT prolongation, or other cardiac abnormalities 1
- Monitor vital signs including pulse and blood pressure, as SNRIs can cause sustained hypertension and increased pulse 1
- Assess for serotonin syndrome features (though less likely after discontinuation): mental status changes, neuromuscular hyperactivity (tremors, clonus, hyperreflexia), and autonomic hyperactivity (hypertension, tachycardia, arrhythmias) 1
Management Strategy
The recommended approach is to restart the SNRI at the previously prescribed dose to resolve symptoms, then implement a much slower tapering schedule. 1, 4
Reinitiation and Gradual Taper
- Resume the previously prescribed SNRI dose if symptoms are intolerable 4
- Once symptoms resolve, begin a gradual dose reduction rather than abrupt cessation 1
- Use non-linear dose-reduction steps (smaller decrements as you approach lower doses) if you have risk factors for withdrawal 5
- Adjust the tapering speed based on emergence of symptoms 5
Risk Factors for Severe Discontinuation Symptoms
You are at higher risk for discontinuation syndrome if: 5
- You experienced withdrawal symptoms with missed doses or non-compliance previously
- A previous attempt to stop was unsuccessful
- You were taking higher than the smallest effective dose
- You were taking venlafaxine (which has higher prevalence of withdrawal symptoms compared to other SNRIs) 2
Important Caveats
Venlafaxine has been specifically associated with more severe discontinuation symptoms and overdose fatalities compared to other SNRIs. 1 If you were taking venlafaxine, extra caution is warranted.
The sensation of "skipped beats" could represent: 1
- Benign premature atrial or ventricular contractions (common in discontinuation syndrome)
- Actual arrhythmias requiring treatment
- Heightened awareness of normal heartbeat variations due to anxiety from discontinuation
Do not attempt to manage this on your own—medical supervision is essential for both cardiac evaluation and safe medication tapering. 1, 4
Monitoring During Taper
When restarting and tapering, your clinician should monitor: 1
- Height, weight, pulse, and blood pressure at each visit
- Emergence of physical symptoms (dizziness, sensory disturbances, GI symptoms)
- Psychological symptoms (anxiety, irritability, mood changes)
- Cardiac symptoms (palpitations, chest discomfort)
The gradual tapering approach minimizes risk of discontinuation symptoms, though the long elimination half-lives of some SNRIs (duloxetine, venlafaxine extended-release, desvenlafaxine) may provide some natural protection. 1