Conditions and symptoms
What Is an Arrhythmia? Why Medicine Labels Mention It
Arrhythmia · say it: uh-RITH-mee-uhAlso written: irregular heartbeat, dysrhythmia, abnormal heart rhythm
Short answer
An arrhythmia is a heartbeat that is too fast, too slow or irregular, because the heart's electrical signals are not working in their usual pattern.
What it means
The heart beats in response to electrical signals. An arrhythmia is any change from the usual rhythm: too fast, too slow, or uneven. Some are harmless and common, such as occasional extra beats. Others, such as atrial fibrillation, need treatment. A rhythm problem with fainting, chest pain or severe breathlessness needs urgent medical help.
Medicine labels mention arrhythmia because some medicines can affect the heart's electrical system, for example by causing QT prolongation, a slow heart rate or low potassium. Labels may ask you to tell your doctor if you have a heart rhythm problem, or to report palpitations, dizziness or fainting.
Palpitations are the feeling of your heartbeat; they are a symptom, not a diagnosis. Tachycardia means a fast rate and bradycardia a slow rate; both can be types of arrhythmia.
Where you may see it
- 'Warnings' sections of labels for some antibiotics, antidepressants and anti-nausea medicines
- Patient leaflets: 'Tell your doctor if you have an irregular heartbeat'
- ECG reports and cardiology letters
📄 How it looks on a report
Use with caution in patients with a history of cardiac arrhythmias.
🙅 What it does not mean
- An arrhythmia warning on a label does not mean the medicine will affect your heart.
- Not every arrhythmia is dangerous; some extra beats are common in healthy people.
- Feeling your heart beat strongly is not always an arrhythmia.
🗒️ Questions to ask your doctor
💊 Medicines whose labels mention “Arrhythmia”
Plain-English explanations of each medicine, from its official FDA label.
- Albuterol
A bronchodilator (a medicine that opens the airways) of the beta-2 adrenergic type. The FDA class is not listed, so this description comes from the label's own wording.
- Amitriptyline
An antidepressant of the tricyclic type
- Amlodipine
a calcium channel blocker, a type of medicine that relaxes blood vessels
- Apixaban
A factor Xa inhibitor, a blood thinner medicine (anticoagulant)
- Atenolol
a beta-blocker (beta-adrenergic blocker). The label describes it as a beta 1-selective, or cardioselective, blocking agent.
- Azithromycin
a macrolide antibacterial (antibiotic) medicine
- Bisoprolol Fumarate
a beta-blocker, which the label describes as a synthetic, beta 1-selective (cardioselective) adrenoceptor blocking agent
- Carvedilol
A beta-blocker. The FDA lists it as both an alpha-adrenergic blocker and a beta-adrenergic blocker.
- Ciprofloxacin
a fluoroquinolone antibacterial medicine
- Citalopram
a selective serotonin reuptake inhibitor (SSRI), a type of antidepressant medicine
🔗 Read more from trusted sources
- “Arrhythmia” on MedlinePlus ↗
US National Library of Medicine
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