Is Tessalon Safe in Patients with Heart Conditions?
Benzonatate (Tessalon) can be used cautiously in patients with stable heart conditions at therapeutic doses, but carries significant cardiac risks in overdose and requires careful patient selection and education.
Cardiac Safety Profile at Therapeutic Doses
Benzonatate is structurally similar to local anesthetics (tetracaine, procaine) and can affect cardiac conduction, though serious cardiac events are rare at prescribed doses 1, 2
At therapeutic plasma concentrations, benzonatate causes partial blockade of cardiac ventricular non-myelinated nerve endings and attenuates cardiovascular reflex responses 3
The drug has endoanesthetic effects on left ventricular receptors similar to lidocaine, which could theoretically affect cardiac function in patients with underlying heart disease 3
Critical Contraindications and High-Risk Populations
Avoid benzonatate in patients with:
Significant cardiac conduction abnormalities - The drug's local anesthetic properties can impair cardiac conduction, similar to other agents in this class 1, 3
Patients taking medications that alter cardiac conduction - Insufficient safety data exists for concurrent use with antiarrhythmic drugs or other conduction-altering medications 4
Severe bradycardia or heart block - Given the drug's effects on cardiac receptors and conduction, these conditions represent relative contraindications 3
Overdose Risks Are Severe
Benzonatate overdose can cause rapid cardiac arrest within 1-2 hours of ingestion, even in previously healthy individuals 1, 2
Cardiac arrest has been documented with ingestion of as few as 10 capsules (2000 mg), with total downtime of 30 minutes and development of bradyarrhythmias 1
Fatal outcomes have been reported in both children and adults, with death occurring within 1 hour of ingestion in suicide attempts 2, 5
The risk is not fully appreciated by the public despite benzonatate being one of the most widely prescribed antitussives 1, 2
Clinical Decision Algorithm
For patients with stable coronary artery disease or controlled hypertension:
- Benzonatate may be prescribed at standard doses (100-200 mg three times daily) with appropriate patient education 1
- Ensure patients understand the importance of not exceeding prescribed doses 2
For patients with active cardiac conditions requiring close monitoring:
- Heart failure with reduced ejection fraction - Consider alternative antitussives; if benzonatate is necessary, use lowest effective dose 6
- Recent myocardial infarction or acute coronary syndrome - Defer use until patient is stabilized on guideline-directed medical therapy 6
- Significant arrhythmias or conduction disease - Avoid benzonatate; choose alternative cough suppressants 4, 3
For patients on multiple cardiac medications:
- Exercise particular caution in patients taking beta-blockers, calcium channel blockers, or antiarrhythmic drugs due to potential additive effects on cardiac conduction 6, 4
- Patients on warfarin or anticoagulants should be monitored closely, as cardiac events could complicate anticoagulation management 6
Essential Patient Safety Measures
Provide explicit overdose warnings - Educate patients that even modest overdoses can be rapidly fatal 1, 2
Prescribe limited quantities - Avoid large prescriptions that could enable intentional or accidental overdose 2
Counsel on proper storage - Keep away from children, as pediatric ingestions have resulted in fatalities 5
Advise against alcohol co-ingestion - Combined use increases risk of adverse cardiac events 1
Common Pitfall to Avoid
The primary clinical error is underestimating benzonatate's cardiac toxicity potential. While it appears to be a "safe" over-the-counter-like medication, its structural similarity to local anesthetics means it carries genuine cardiac risks, particularly in overdose or in patients with pre-existing conduction abnormalities 1, 2, 3. The narrow therapeutic-to-toxic window demands respect and careful patient selection.