What the FDA labels say about taking them together
Flecainide and mexiletine
Mexiletine's FDA label of May 14, 2026 names flecainide in its warnings section; the flecainide label PlainMeds reads does not name mexiletine.
Check it at the source: the flecainide FDA label on DailyMed (effective June 11, 2026, Amneal Pharmaceuticals of New York LLC); the mexiletine FDA label on DailyMed (effective May 14, 2026, Macleods Pharmaceuticals Limited).
What does the flecainide label say about mexiletine?
Flecainide's label (effective June 11, 2026) does not name mexiletine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Flecainide Acetate), Amneal Pharmaceuticals of New York LLC, effective June 11, 2026 (SPL set ee9595d5-08a1-4529-9215-ddc3c7f929c4), via openFDA; the full label on DailyMed
What does the mexiletine label say about flecainide?
Mexiletine label, warningsWARNINGS BOXED WARNING WARNINGS Mortality In the National Heart, Lung and Blood Institute’s Cardiac Arrhythmia Suppression Trial (CAST), a long-term, multicentered, randomized, double-blind study in patients with asymptomatic non-life-threatening ventricular arrhythmias who had a myocardial infarction more than six days but less than two years previously, an excessive mortality or non-fatal cardiac arrest rate (7.7%) was seen in patients treated with encainide or flecainide compared with that seen in patients assigned to carefully matched placebo-treated groups (3.0%).
Source: FDA drug label (Mexiletine Hydrochloride), Macleods Pharmaceuticals Limited, effective May 14, 2026 (SPL set a61a07f6-0b48-4dcd-ad42-5d90f6e69ab1), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Flecainide | Mexiletine | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.171 per tablet 100 mg tablet | $0.222 per capsule 150 mg capsule |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once