Benzonatate: Indications, Mechanism of Action, Dosage, Side Effects, Warnings and Interactions

It is a non-narcotic oral antitussive chemically related to the anesthetic agents of the p-aminobenzoic acid class (e.g., tetracaine, procaine).

It shares with them several characteristics of its pharmacology and toxicology; it is considered a very effective alternative to opioid-type antitussives, as is the case of codeine.

So it seems to have a suppressive effect on cough more sustainably than other oral antitussives.

Derived from a long chain of polyglycol, it is structurally related to procaine, which relieves the symptoms of nonproductive cough produced by colds and by inhaling irritants.

Its effect starts at 20 min and lasts up to 8 h. It is well absorbed in the digestive tract, and its metabolites are eliminated in the urine.

Chemical formula

  • C30H53NO11.


  • Suppositories for pediatric use containing 50 mg Benzonatate.
  • Suppositories for adults containing 100 mg Benzonatate 100 mg.
  • Capsule containing 100 mg Benzonatate.
  • Pearls containing 100 mg Benzonatate.


It is indicated for the symptomatic relief of irritative cough associated with certain pleuropulmonary and bronchopulmonary conditions.

In conditions such as acute pneumonia and bronchitis, some chronic respiratory diseases include emphysema, bronchial asthma, pleuritis, pulmonary tuberculosis, pneumoconiosis, respiratory tract tumors, and cough of the common cold.


Mechanism of action

The mechanism of action of the Benzonatate is executed centrally and peripherally.

Benzonatate produces a local anesthetic effect by acting on the respiratory tract’s vagal receptors and fibers, blocking the cough reflex from where it originates.

At the central level, Benzonatate suppresses the cough reflex transmission at the medulla level.



  • Oral administration:  100 mg is prescribed every eighth. The maximum dose should never exceed 600 mg per day.
  • Rectal administration:  suppository of 50 or 100 mg is prescribed every eighth.


  • Oral administration: Dosage has not been established for children under ten. For children older than ten years, the dose of adults is administered.
  • Rectal administration: A suppository of 50 mg every 8 hours is prescribed for children older than ten years.

Side effects

Severe hypersensitivity reactions have been reported among the side effects of Benzonatate administration, including:

  • Bronchospasm, laryngospasm, and cardiovascular collapse are possibly related to local anesthesia that occurs when chewing or dissolving the capsule in the mouth instead of swallowing it completely.
  • In isolated cases, dermal reactions have been reported, such as the presence of pruritus and rash.
  • Also, minor gastrointestinal discomforts include nausea, constipation, and abdominal pain.
  • There are alterations in the central nervous system such as sedation, drowsiness, headaches, and dizziness.
  • Symptoms such as nasal congestion, a burning sensation in the eyes, and tightness in the chest have also been reported.
  • Isolated cases of strange behavior have been obtained, including mental confusion and visual hallucinations.
  • Moreover, in the use of suppositories, local irritation has occurred.

Warnings and contraindications

  • Do not administer the drug in case of hypersensitivity to Benzonatate or other substances linked to local anesthetics such as procaine and any formula components.
  • Benzonatate is contraindicated in children under six years of age.
  • When administering the pearl, it should be swallowed whole without chewing it.
  • It should not be administered in pregnant women since there have been no studies with Benzonatate, so it is unknown if the medicine can cause some damage to the fetus.
  • It is also unknown if it can affect reproductive capacity.
  • Neither should be administered during the lactation period; there is no information if the Benzonatate is excreted by breast milk.


The frequent use of Benzonatate can increase the effects of central nervous system depressant drugs.

Symptoms and management of overdose or accidental ingestion

An overdose of Benzonatate can be fatal.

If pearls are chewed or dissolved, oropharyngeal anesthesia will be produced very quickly in the case of pearls.

The effects of an overdose are the stimulation of the central nervous system and can cause restlessness and tremors with chronic seizures and deep depression of the central nervous system.

There is no known specific antidote.

The treatments generally consist of gastric lavage and the use of activated charcoal. If necessary, aspiration of gastric contents should be performed.

Seizures should be managed with intravenous barbiturates.

While the effects of the overdose last, no type of central nervous system stimulants should be used.

Cardiovascular, renal, and respiratory functions should be intensively managed in cases of overdose.

Other symptoms of an overdose are:
  • Giddiness .
  • Sickness.
  • Drunkenness
  • Depression of the central nervous system.
  • Respiratory insufficiencies.