MAJOR — Use With Caution
FDA-documented interaction. CYP2D6 inhibition increases flecainide levels. Risk of pro-arrhythmic toxicity. Monitor flecainide levels and ECG.
Evidence level: STRONG
Prozac can increase flecainide (a heart rhythm medication) levels by blocking the enzyme that processes it. Since flecainide has a narrow safety range and can actually CAUSE heart rhythm problems at high levels, this is a dangerous combination.
Fluoxetine inhibits CYP2D6. Flecainide is metabolized by CYP2D6. Increased flecainide levels can cause pro-arrhythmic effects. FDA flecainide label warns about CYP2D6 inhibitors.
If prescribed both, your flecainide dose may need reduction. Report any new palpitations, dizziness, or visual disturbances. ECG monitoring is recommended.
Take Fluoxetine at the same time each day — morning is most common to avoid sleep disruption. Flecainide follows its prescribed schedule. SSRIs have a long half-life, so consistency matters more than the exact hour.
Higher risk for: elderly, those on multiple serotonergic drugs, people with liver impairment, CYP2D6 poor metabolizers, recent dose changes, or concurrent use of MAOIs or triptans.
New or worsening palpitations, dizziness, visual disturbances, fainting, worsening heart rhythm
Monitor flecainide levels and ECG. Consider CYP2D6-sparing antidepressant (sertraline, citalopram). Reduce flecainide dose if needed.
Discuss this combination with your prescriber. They may adjust timing, dosing, or switch to an alternative with fewer interaction risks. Never stop an antidepressant abruptly — taper under medical guidance.
Prozac can increase flecainide (a heart rhythm medication) levels by blocking the enzyme that processes it. Since flecainide has a narrow safety range and can actually CAUSE heart rhythm problems at high levels, this is a dangerous combination.
Take Fluoxetine at the same time each day — morning is most common to avoid sleep disruption. Flecainide follows its prescribed schedule. SSRIs have a long half-life, so consistency matters more than the exact hour.
New or worsening palpitations, dizziness, visual disturbances, fainting, worsening heart rhythm
Discuss this combination with your prescriber. They may adjust timing, dosing, or switch to an alternative with fewer interaction risks. Never stop an antidepressant abruptly — taper under medical guidance.
Monitor flecainide levels and ECG. Consider CYP2D6-sparing antidepressant (sertraline, citalopram). Reduce flecainide dose if needed.
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