Benzonatate or 2,5,8,11,14,17,20,23,26-nonaoxaoctacosan-28-yl para-butylaminobenzoate is a non-narcotic oral antitussive (cough suppressant) drug, taken orally, which works by anesthetizing the tissues of the lungs and pleura responsible for the cough reflex. It has a numbing action similar to that of benzocaine that calms the stretch sensors in the lungs. It is the stretching of these sensors with breathing that causes the cough. Benzonatate begins to work within 15 to 20 minutes. Its effects last for approximately 3 hours. It is sold under the brand name Tessalon Perles (gelcaps) or Tessalon Capsules. The medication must be swallowed whole. If the capsules are bitten into or sucked on, it may make the mouth numb and in some cases cause choking. It is chemically related to other ester anesthetics such as procaine. Benzonatate is unrelated to codeine and other narcotics that are frequently used to suppress coughs. (Another frequently used cough suppressant, dextromethorphan, which is found in many over-the-counter cough and cold preparations, is a derivative of the narcotics.) Benzonatate was approved by the FDA in 1958.