What cough medication can a patient with a history of atrial fibrillation (afib), Watchman device, and taking anastrazole (Arimidex) take?

Safe Cough Medication Options for Patients with Atrial Fibrillation, Watchman Device, and Anastrozole

For this patient, benzonatate (Tessalon Perles) is the safest first-line cough suppressant, as it has no cardiac effects, no QT prolongation risk, and no drug interactions with antiarrhythmic medications or anastrozole. 1

Primary Recommendation: Benzonatate

• Benzonatate is FDA-approved for symptomatic relief of cough and works peripherally by anesthetizing stretch receptors in the respiratory tract, avoiding any cardiac effects. 1
• This medication has no impact on heart rate, rhythm, or QT interval, making it ideal for patients with atrial fibrillation regardless of their rate control or rhythm control medications. 1
• There are no known interactions with anticoagulants (which this patient likely takes given the Watchman device history) or with anastrozole. 1
• Typical dosing is 100-200 mg three times daily as needed for cough. 1

Alternative Option: Dextromethorphan

• Dextromethorphan is a widely available over-the-counter cough suppressant that can be used as a second-line option, though evidence for its efficacy in clinically significant cough is limited. 2, 3
• Dextromethorphan works centrally to suppress the cough reflex and has demonstrated objective reduction in cough frequency in some studies, though subjective improvement may not differ significantly from placebo. 3, 4
• Importantly, dextromethorphan has no significant cardiac effects and does not prolong the QT interval, making it safe in patients with atrial fibrillation. 2, 5
• The typical dose is 10-30 mg every 4-6 hours, with a maximum of 120 mg per day. 2, 6
• At therapeutic doses, dextromethorphan is safe and non-narcotic, though abuse at very high doses (>1500 mg/day) can cause psychosis. 7

Critical Medications to AVOID

Avoid Medications with Antimuscarinic/Anticholinergic Properties

• Many combination cough and cold preparations contain antihistamines (diphenhydramine, chlorpheniramine) or anticholinergics that can potentially prolong the QT interval and worsen arrhythmias in patients with atrial fibrillation. 8
• These agents pose particular risk if the patient is taking antiarrhythmic drugs like amiodarone, dofetilide, or quinidine for rhythm control. 8

Avoid Decongestants

• Pseudoephedrine and phenylephrine should be avoided as they can increase heart rate and potentially trigger atrial fibrillation episodes. 9
• These sympathomimetic agents can interfere with rate control strategies and increase cardiovascular risk. 9

Special Considerations for This Patient

Watchman Device Context

• The presence of a Watchman device (left atrial appendage closure device) indicates this patient has a history of atrial fibrillation with elevated stroke risk but may have contraindications to long-term anticoagulation. 9
• Cough medications should not interfere with any antiplatelet therapy (typically dual antiplatelet therapy for 45 days post-Watchman, then aspirin alone). 9
• Neither benzonatate nor dextromethorphan affects platelet function or interacts with antiplatelet agents. 1, 2

Anastrozole Considerations

• Anastrozole is an aromatase inhibitor used for breast cancer treatment and has no significant drug interactions with benzonatate or dextromethorphan. 1, 2
• There are no contraindications to using standard cough suppressants in patients on anastrozole therapy. 1, 2

Common Pitfalls to Avoid

• Do not assume all over-the-counter cough medications are safe—always check the active ingredients for sympathomimetics, antihistamines, or other agents that may affect cardiac rhythm. 8
• Avoid combination products that contain multiple active ingredients, as these often include decongestants or anticholinergics that pose cardiac risks. 8
• If the cough is related to an ACE inhibitor (if the patient is taking one for heart failure or hypertension), the only effective treatment is discontinuation of the ACE inhibitor and switching to an ARB. 9

When to Investigate Further

• If cough persists despite appropriate suppressant therapy, evaluate for ACE inhibitor-induced cough (resolves 1-4 weeks after discontinuation, though may take up to 3 months in some patients). 9
• Consider pulmonary causes including heart failure-related pulmonary congestion, pulmonary embolism (given atrial fibrillation history), or infectious etiologies. 9
• Assess medication list for other potential causes of cough beyond ACE inhibitors. 9