What happens if you overdose on benzonatate

LAs will act on bronchial smooth muscle at non-overdose concentrations and may impact respiratory function at near overdose concentrations Like other LAs, benzonatate is a potent voltage-gated sodium channel inhibitor, yet other unknown mechanisms may be at work 7 , 10 , As an oral antitussive agent, it acts by anesthetizing the pulmonary stretch receptors with a 15—min onset of action for a duration of 3—8 h 7 , 8 , 21 , Adverse reactions to benzonatate include nausea, dizziness, headache, sedation, somnolence and, in some cases, numbness of the tongue.

Some of these systemic symptoms are analogous to the pre-convulsive effects of systemic local anesthetic toxicity which escalate to visual disturbances, muscle twitching and tremors 16 , 19 , With further increase above a therapeutic concentration, the convulsive phase may begin with a generalized tonic-clonic episode that can deteriorate into CNS depression resulting in respiratory arrest; additionally, these LAs have dose-related negative cardiovascular effects including conduction changes, hypotension and cardiac arrest Related symptoms may also occur due to unintended local anesthetic effect in the esophageal cavity.

When a therapeutic dose, administered as a single capsule, is chewed or crushed, there is potential for bronchospasm, laryngospasm, seizures and cardiovascular collapse which mimics the systemic toxicity seen at high doses 6 , 15 , 19 , A narrow safety margin for benzonatate has been demonstrated by overdose case studies 13 , 20 , 22 , In several of the published over-ingestion cases, as well as those observed in our office, only a small handful of pills was enough to cause seizures, a cardiac event and death.

Interestingly, the product insert directs one to not double up a missed dose of benzonatate and only take a maximum of mg at a time.

If supportive care is administered rapidly, intravenous lipid emulsion ILE may be successful in resolving some benzonatate toxicity cases 13 , 20 , 23 , Benzonatate, 4- butylamino benzoic acid BABA metabolite and structurally related tetracaine. Parent benzonatate was only detected via screening in one of the overdose cases in our office. It appeared as a late-eluting compound after trazodone in the base screen and was quantitated by a reference laboratory using traditional HPLC methodology.

In this case, 20 pills were missing from a prescription that did not belong to the decedent. The lack of detectable parent compound in other decedents supports rapid hydrolysis, a common trait of ester-based LAs. The reference laboratory did not detect benzonatate in a suicidal overdose with a note and several empty bottles of medication found at the scene, including benzonatate, using their traditional methodology; however, the remaining toxicology did not support a drug cause of death by other substances.

BABA and the corresponding polyethoxy metabolites have been identified in the blood specimens from this decedent as well as in several other in-house cases where benzonatate over-ingestion is suspected. In-house analysis of benzonatate capsules obtained from two different manufacturers Ascend Laboratories and Zydus Pharmaceuticals indicate that the average abundance of 7—9 repeating units is generally expected, but is not uniform between manufacturers, similar to reports in the literature 7 , 10 , The reference standard for benzonatate, available from USP, is a mixture of n -ethoxy analog compounds with an average molecular weight of Evans et al.

Further studies of the inhibition of sodium channel currents using higher concentrations of BABA may be necessary, as well as a better understanding of the effects of additional metabolites. Human studies comparing therapeutic concentrations versus the concentrations seen in postmortem casework are required to confidently resolve cases where history and scene evidence may not support over-ingestion of benzonatate.

The pseudocholinesterase deficient portion of the population may be prone to increased sensitivities of this cough medication 16 because of diminished ability to hydrolyze the parent compound and thus potential prolongation of increased benzonatate activity. Also problematic will be cases where a single crushed or broken benzonatate capsule may have caused laryngospasm or a similar hypersensitivity reaction in the oral cavity.

Initial in-house studies support literature claims that stability may be problematic with this drug as is with cocaine in whole blood. Even more challenging is the rapid metabolism of the series of n -ethoxy parent compounds without a suitable pure standard available for quantitation of each specific molecular weight. Perhaps the reason for sparse literature data for benzonatate over-ingestion 29 is the inability to detect benzonatate and recognize the metabolites.

The recommendation in The Medical Letter warning indicates that opioid-containing antitussives may be a safer choice Based on the narrow safety margin, the lack of reliable human-subject studies, and the undetermined in-house cases in North Carolina waiting for quantitation, that may be a logical assessment.

Reynolds , S. Trend in Pharmacological Sciences , 25 , — Google Scholar. Dicpinigaitis , P. Respiratory Medicine , , — Current Opinion in Pharmacology , 22 , 24 — Understanding the Epidemic.

Drug Overdose deaths in the United States hit record numbers in Pharmacotherapy , 33 , 38 — Evans , M. Neuropharmcology , , — Pfizer, Inc. Baselt , R. Disposition of Toxic Drugs and Chemicals in Man , 9th edition. Google Preview. Crouch , B. Clinical Toxicology , 36 , — Food and Drug Administration. FDA Drug Safety Communication: death resulting from overdose after accidental ingestion of Tessalon benzonatate by children under 10 years of age.

Abramowicz, Mark In brief: benzonatate warning. The Medical Letter on Drugs and Therapeutics , 53 , 9. Signs and symptoms of benzonatate overdose can occur rapidly after ingestion within minutes and may include restlessness, tremors, convulsions, coma, and cardiac arrest. Benzonatate capsules are to be swallowed whole and are not to be broken, chewed, dissolved, or crushed. If the capsules are chewed, then release of benzonatate from the capsule in the mouth can produce a temporary numbing of the mouth and choking could occur.

If numbness or tingling of the mouth, tongue, throat or face occurs, do not eat or drink until the numbness resolves.

If the symptoms worsen or persist, seek medical attention. Overdose of benzonatate has been reported in adults and adolescents.

If you miss a dose of benzonatate, skip that dose and take the next dose at the next scheduled time. Do not take more than mg of benzonatate at one time. Patients and caregivers should dispose of any leftover benzonatate in their household trash see Federal Drug Disposal Guidelines : Take the medication out of its original container and mix it with an undesirable substance, such as used coffee grounds or kitty litter.

The medication will be less appealing to children and pets, and unrecognizable to people who may intentionally go through your trash. Put the medication in a sealable bag, empty can with a tight lid, or other container to prevent it from breaking out of a garbage bag. Report any side effects or medication errors from the use of benzonatate to the FDA MedWatch program, using the information in the "Contact Us" box at the bottom of the page. Additional Information for Healthcare Professionals Advise patients to keep benzonatate in a child-resistant container and to store it out of reach of children.

Counsel patients about how to properly dispose of leftover benzonatate after they have stopped taking the medication see Federal Drug Disposal Guidelines. Advise parents and caretakers to call the Poison Control Center and to seek medical attention immediately if a child accidentally ingests benzonatate. Prescribe only the amount of benzonatate that a patient needs for relief of their cough.

Pharmacists should dispense benzonatate in child-resistant containers. Recognize the signs and symptoms of benzonatate overdose, which may include restlessness, tremors, convulsions, coma, and cardiac arrest. A recently published report describes the case of a year-old female patient who experienced seizures and cardiac arrest following toxic ingestion of benzonatate, a commonly prescribed nonnarcotic antitussive agent.

The patient, who was previously healthy, was brought to the emergency department ED after being found unresponsive on her couch. An unmarked pill bottle was found nearby and brought to the ED by responding emergency medical services personnel. Return of spontaneous circulation was achieved after advanced cardiac life support was executed. It was later determined that the patient had ingested less than 30 benzonatate capsules mg each in addition to alcohol approximately 2 hours before presenting to the ED.