What Is the Benzonatate Mechanism of Action: An Ultimate Guide 2023

The Benzonatate mechanism of action is critical for people who need this drug to treat cough. In this article, access more information about Benzonatate and how it takes effect. Other things you may be wondering about will also be mentioned here.

What is Benzonatate?  

Benzonatate is an oral medication used to suppress coughs. It has an anesthetic (numbing) effect similar to benzocaine, paralyzing the stretch sensors in the lungs. Breathing causes these sensors to stretch, causing coughing. It has no inhibitory effect on the respiratory center at recommended doses. The effect appears within 15-20 minutes after administration and the duration of action is approximately 3-8 hours. 

Benzonatate suppresses cough in acute and chronic respiratory diseases. It works by desensitizing stretch receptors in the lungs involved in the cough reflex. Clinical studies on benzoate are limited. However, previous studies have shown that experimentally induced cough and subjectively measured pathological cough are suppressed by benzoate.

Moreover, Benzonatate is unrelated to narcotics like codeine, which are commonly used to suppress coughs. (Dextromethorphan, another commonly used cough medicine, is found in many over-the-counter cough and cold remedies and is a derivative of narcotics.)  How can Benzonatate take effect? Learn the Benzonatate mechanism of action in the next part.

 Benzonatate Mechanism of Action

What is the Benzonatate mechanism of action? Benzonatate acts peripherally by anesthetizing stretch receptors of vagal afferent fibers in the alveoli of the lungs, bronchi, and pleura. The drug can also act centrally by inhibiting the transmission of the cough reflex at the medullary level, where vagal afferent impulses are transmitted to motor neurons. In patients with asthma, intravenous benzoate increased minute ventilation, respiratory rate, and respiratory depth.

However, total lung volume and expiratory flow were unchanged. Benzoate has no depressant effect on the respiratory center at recommended oral doses. However, in overdose, the pharmacology of benzoates becomes similar to that of other ester-type local anesthetics. Clinical effects include initial CNS stimulation, subsequent CNS depression, and airway compromise.

When applied topically, e.g., to the oropharynx before intubation or endoscopy, benzoates act like other local anesthetics. This drug blocks the generation and transmission of nerve impulses at the cell membrane level. Local anesthetics bind directly to the intracellular portion of voltage-gated sodium channels. This reduces the rate of membrane depolarization, thereby increasing the threshold for electrical excitation. Blockade affects all nerve fibers in the following order:

There are vegetative, sensory, and motor effects that decrease in reverse order. Loss of neurological function manifests clinically as Pain, temperature, touch, proprioception, and skeletal muscle tone.

Effective anesthesia requires direct penetration of the nerve membrane. This is accomplished by applying benzoate around the nerve trunks or ganglia that supply the area to be anesthetized. Benzonatates induce anesthesia in approximately 1-2 minutes after direct topical application to the oropharynx. This is clinically reflected in the loss of the gag reflex.  

Other FAQs about Benzonatate

1. What are the side effects of Benzonatate?

Although the Benzonatate mechanism of action works in many situations, it also has several side effects. The most common negative effects of Benzonatate are lethargy, headaches, slight lightheadedness, constipation, nausea, and vomiting. Other possible side effects that have been documented include nasal congestion, hallucinations, itching, skin irritation, indigestion, disorientation, and numbness in the chest.

If Benzonatate capsules are sucked or chewed instead of being swallowed, there is a risk of experiencing severe reactions to hypersensitivity, such as spasms in the airways or cardiovascular collapse. Moreover, it is not advisable to administer Benzonatate to children under the age of 10 because there have been reported incidents of accidental overdose and death in this age group.

1. How to store Benzonatate at home?

Keep capsules in a container out of reach of children and always keep them out of reach of children. Mix unused medicine with used coffee grounds or cat litter and discard in a sealable bag, empty jar, or container.  As for the temperature, store capsules at room temperature between 15°C and 30°C (59°F and 86°F). 

1. Is Benzonatate safe for pregnant women?

Little information is available about the effects of benzoate on the fetus. Doctors may use it during pregnancy if they determine that its benefits outweigh the potential but unknown risks.

It is unknown whether benzoate is excreted in breast milk.  

Conclusion:

The post has introduced the Benzonatate mechanism of action and other information about this drug. It has a great effect to heal cough. But it also has several side effects. You’d better follow the doctor's advice when using it.