After absorption and circulation to the respiratory tract, benzonatate acts as a local anesthetic, decreasing the sensitivity of vagal afferent fibers and stretch receptors in the bronchi, alveoli, and pleura in the lower airway and lung. This dampens their activity and reduces the cough reflex. Benzonatate also has central antitussive activity on the cough center in central nervous system at the level of the medulla. However, there is minimal inhibition of the respiratory center at a therapeutic dosage. Pharmacokinetics
The antitussive effect of benzonatate begins within 15 to 20 minutes after oral administration and typically lasts between 3 and 8 hours.Benzonatate is hydrolyzed by plasma butyrylcholinesterase (BChE) to the metabolite 4-(butylamino)benzoic acid (BABA) as well as polyethylene glycol monomethyl esters. Like many other local anesthetic esters, the hydrolysis of the parent compound is rapid. There are concerns that those with pseudocholinesterase deficiencies may have an increased sensitivity to benzonatate as this hydrolysis is impaired, leading to increased levels of circulating medication. Chemical structure
Benzonatate is a butylamine, structurally related to other polyglycol ester local anesthetics such as procaine and tetracaine. The molecular weight of benzonatate is 603.7 g/mol. However, the reference standard for benzonatate is a mixture of n-ethoxy compounds, differing in the abundance of 7-9 repeating units, with an average molecular weight of 612.23 g/mol. There is also evidence that the compound is not uniform between manufacturers. Society and culture
Benzonatate was first made available in the U.S. in 1958 as a prescription medication for the treatment of cough in individuals over the age of 10.
Benzonatate, sold under the brand name Tessalon among others, is a medication used to try to help with the symptoms of cough and hiccups. It is taken by mouth. Use is not recommended in those under the age of ten. Effects generally begin within 20 minutes and last up to eight hours.Side effects include sleepiness, dizziness, headache, upset stomach, skin rash, hallucinations, and allergic reactions. Excessive doses may cause seizures, irregular heartbeat, and death. Chewing or sucking on the capsule can lead to laryngospasm, bronchospasm, and circulatory collapse. It is unclear if use in pregnancy or breastfeeding is safe. It works by numbing stretch receptors in the lungs and suppressing the cough reflex in the brain.Benzonatate was approved for medical use in the United States in 1958. It is available as a generic medication. It is not available in many countries. In 2019, it was the 105th most commonly prescribed medication in the United States, with more than 6 million prescriptions. Medical uses
Cough
Benzonatate is a prescription non-opioid alternative for the symptomatic relief of cough. It has been shown to improve cough associated with a variety of respiratory conditions including asthma, bronchitis, pneumonia, tuberculosis, pneumothorax, opiate-resistant cough in lung cancer, and emphysema.Benzonatate also reduces the consistency and volume of sputum production associated with cough in those with chronic obstructive pulmonary disorder (COPD).Compared to codeine, benzonatate has been shown to be more effective in reducing the frequency of induced cough in experiments.Benzonatate does not treat the underlying cause of the cough.