What is Benzonatate and How Does It Work?
Benzonatate is a non-narcotic, prescription antitussive medication used for the symptomatic relief of cough. Approved by the FDA since 1958, this anesthetic drug is chemically related to other local anesthetics like procaine and tetracaine. The medication is typically marketed as small, liquid-filled capsules, sometimes called “perles”.
The primary mechanism of action involves a peripheral effect on the respiratory system.
Benzonatate's Mechanism of Action
- Anesthetizes Stretch Receptors: After being swallowed whole, the active ingredient is absorbed and travels through the bloodstream to the lungs. Here, it acts as a local anesthetic, numbing the stretch receptors of the vagal afferent fibers in the bronchi, alveoli, and pleura.
- Dampens Cough Reflex: By desensitizing these nerves in the lower airways and lungs, benzonatate reduces the signals that trigger the cough reflex.
- Central Effect: The drug is also believed to have a central effect, suppressing the cough center in the medulla, located in the brainstem.
- Non-Sedating at Therapeutic Doses: Unlike some other cough suppressants, benzonatate does not typically depress the central nervous system or respiratory function when used as prescribed.
Indications and Uses for Benzonatate
Benzonatate is prescribed to relieve non-productive cough associated with various respiratory conditions. It is only approved for use in individuals 10 years of age and older.
Common Applications
- Acute respiratory conditions: This includes coughs caused by the common cold, flu, bronchitis, and pneumonia.
- Chronic respiratory conditions: It has also been used for coughs related to pulmonary emphysema, bronchial asthma, and chronic obstructive pulmonary disease (COPD).
- Opiate-resistant cough: In some cases, it may provide relief for patients with coughs that do not respond to opioid-based antitussives.
It is crucial to note that benzonatate should not be used for chronic coughs that produce a large amount of mucus or phlegm, such as those associated with smoking.
Benzonatate vs. Other Common Cough Medications
Benzonatate is one of several types of antitussive and cough relief medications. Here is a comparison with two common alternatives, dextromethorphan and guaifenesin, based on information from GoodRx.
| Feature | Benzonatate (e.g., Tessalon Perles) | Dextromethorphan (e.g., Delsym) | Guaifenesin (e.g., Mucinex) |
|---|---|---|---|
| Availability | Prescription only | Over-the-counter (OTC) | OTC and prescription |
| Mechanism of Action | Peripheral anesthetic effect, numbing nerves in the lungs and airways | Central nervous system depressant, works on the cough center in the brain | Expectorant, thins mucus to make coughs more productive |
| Best For | Dry, non-productive coughs | Dry coughs | Chest congestion and productive coughs |
| Administration | Swallow capsules whole; never chew, crush, or dissolve | Various forms: tablets, liquids, extended-release | Various forms: tablets, liquids, extended-release |
| Age Range | 10 years and older | Children and adults (age varies by product) | 12 years and older for extended-release products |
| Key Risks | Fatal overdose in children, serious allergic reactions if chewed | Serotonin syndrome risk when combined with MAOIs | Generally well-tolerated; often found in multi-symptom products |
Crucial Safety Warnings and Proper Administration
Due to its potential for serious side effects and overdose, especially in children, benzonatate carries a boxed warning from the FDA. Proper administration is not only important for effectiveness but is critical for safety.
Serious Risks and Warnings
- Fatal Overdose in Children: Accidental ingestion of benzonatate by young children can be fatal, with deaths reported in children under 10 years of age, sometimes after ingesting only one or two capsules. Signs of overdose can appear within 15 to 20 minutes and may include restlessness, tremors, convulsions, coma, and cardiac arrest.
- Serious Hypersensitivity: If a capsule is chewed or dissolved in the mouth, it can release a local anesthetic effect that numbs the mouth and throat. This can lead to serious hypersensitivity reactions, such as bronchospasm, laryngospasm, and cardiovascular collapse.
- Psychiatric Effects: In rare cases, bizarre behavior, including mental confusion and hallucinations, has been reported. This risk may be higher for individuals taking certain mental health medications.
- Drug Interactions: Additive central nervous system (CNS) depression can occur when benzonatate is combined with other sedating substances, including alcohol, opioids, and antihistamines.
Proper Administration Guidelines
To minimize risks, patients must follow these guidelines strictly:
- Swallow the capsules whole with a glass of water.
- Do not break, chew, dissolve, cut, or crush the capsules under any circumstances.
- If accidental chewing occurs and numbness develops, avoid eating or drinking until the feeling returns to prevent choking.
- Always store benzonatate in its child-resistant container and keep it out of reach of children.
- In case of accidental ingestion, immediately contact Poison Control and seek emergency medical attention.
Conclusion
Benzonatate is unequivocally used as a drug, specifically as a prescription antitussive for controlling cough in patients aged 10 and older. Its unique mechanism of action, numbing the peripheral cough receptors, makes it a valuable option for certain respiratory conditions. However, its effectiveness is balanced by significant safety considerations, most notably the high risk of fatal overdose in children and serious adverse reactions if the capsule is improperly administered. By adhering to strict proper use guidelines, patients can utilize the drug's benefits while minimizing its inherent risks. As with any prescription medication, a thorough discussion with a healthcare provider is essential to determine if benzonatate is the right treatment option for your specific condition.
