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Medications That May Trigger or Worsen Atrial Fibrillation

Atrial fibrillation (AFib) is a common heart rhythm disorder characterized by an irregular and often rapid heartbeat. While AFib can be caused by a variety of health conditions, certain medications and substances may also trigger episodes or worsen symptoms in people who are susceptible.

If you have been diagnosed with AFib or are at risk, it’s important to know which medications and over-the-counter products could affect your heart rhythm — and to discuss all drugs and supplements with your healthcare provider.

How Medications Influence AFib

AFib occurs when the electrical signals in the upper chambers of the heart (atria) become disorganized, leading to an irregular heartbeat. Certain medications and substances can:

  • Increase heart rate or blood pressure
  • Stimulate the nervous system
  • Alter electrolyte balance
  • Interact with other heart medications

All of these factors can potentially trigger an AFib episode or make existing symptoms worse.

Medications and Substances That May Trigger or Worsen AFib

1. Decongestants and Cold Medications

Over-the-counter drugs that contain pseudoephedrine or phenylephrine (commonly found in cold, flu, and allergy medications) are known stimulants that can increase heart rate and blood pressure. These may trigger AFib, especially in sensitive individuals.

Examples:

  • Sudafed
  • DayQuil
  • NyQuil Severe
  • Some combination allergy meds

Tip: Look for “heart-safe” or non-stimulant alternatives and consult your doctor before using cold medications.

2. Stimulants and Weight Loss Medications

Stimulant drugs can increase adrenaline and put stress on the heart, potentially leading to arrhythmias like AFib.

Common triggers include:

  • Amphetamines (used for ADHD or narcolepsy)
  • Ephedra (banned in the U.S. but still found in some supplements)
  • Some over-the-counter weight loss pills or energy boosters

Examples:

  • Adderall
  • Ritalin
  • Caffeine-containing weight loss supplements

3. Certain Antidepressants and Antipsychotics

Some psychiatric medications can affect heart rhythm, particularly those that prolong the QT interval or alter electrical conduction in the heart.

Examples:

  • Tricyclic antidepressants (e.g., amitriptyline)
  • Certain SSRIs or SNRIs (e.g., citalopram at high doses)
  • Antipsychotics like haloperidol or risperidone

Always inform your psychiatrist or prescribing doctor of any heart rhythm history, including AFib.

4. Corticosteroids

Steroid medications used to treat inflammation (e.g., for asthma, autoimmune disease, or allergies) can sometimes cause electrolyte imbalances or elevate blood pressure — both of which can contribute to AFib onset.

Examples:

  • Prednisone
  • Methylprednisolone (Medrol)

Short-term use may carry less risk, but long-term or high-dose use should be monitored.

5. Thyroid Medications

Too much thyroid hormone — whether from the body or medication — increases metabolism and heart rate, raising the risk for AFib.

Example:

  • Levothyroxine (especially if dosed too high)

A simple thyroid blood test can help ensure proper dosing if you’re on thyroid medication and experiencing palpitations or irregular heartbeats.

6. Certain Chemotherapy Drugs

Some cancer treatments can affect the heart’s electrical system, causing arrhythmias as a side effect.

Examples:

  • Doxorubicin
  • Ibrutinib
  • Trastuzumab

Oncology teams typically monitor heart function closely during treatment, especially in patients with known heart issues.

7. Alcohol and Recreational Drugs

Though not prescription medications, alcohol and certain illicit drugs (like cocaine or methamphetamine) are well-known AFib triggers. Even moderate alcohol intake can trigger "holiday heart syndrome" — a form of AFib that occurs after heavy drinking.

What to Do If You’re Concerned

If you suspect a medication is triggering or worsening your AFib, follow these steps:

  • Don’t stop the medication abruptly without medical guidance.
  • Track symptoms, noting when they occur and what medications you’ve taken.
  • Consult your healthcare provider, especially a cardiologist or electrophysiologist, to review your medication list.
  • Ask about safer alternatives or dose adjustments.
  • Bring a complete list of prescriptions, supplements, and over-the-counter products to every appointment.

Final Thoughts

While many medications are safe and effective, some can increase the risk of atrial fibrillation in people who are predisposed. By being proactive and working closely with your healthcare provider, you can manage your AFib and avoid unnecessary triggers.