II. Background
- Tessalon Perles appear candy-like and could be ingested by young children
- Capsules are toxic if broken open (e.g. chewed, sucked) or taken in Overdose
- Single capsule may be lethal to child if the capsule leaks its liquid contents into the mouth
- McLawhorn (2013) Pharmacotherapy 33:38-43 +PMID:23307543 [PubMed]
- Narrow therapeutic range
- A small handful of capsules in Overdose could be lethal in adults
- Lethal effects of Benzonatate have likely been underestimated in past
- Benzonatate is rapidly metabolized and only recently have its metabolites been tested in autopsy cases
III. Mechanism: Toxicity
- Sodium Channel Blocker
- Anesthetizes respiratory tract vagal stretch receptors
IV. Pharmacokinetics
- Adults
- Toxicity at >600 mg
- Young children
- Toxicity at >100 mg (esp. capsule chewed or crushed)
V. Signs: Toxicity
- Rapid onset of symptoms (within 30 minutes of ingestion)
- Respiratory
- Laryngospasm or Bronchospasm
- Aspiration
- Respiratory Arrest
- Cardiovascular
- Hypotension or cardiovascular collapse
- Tachycardia
- Ventricular Tachycardia
- Torsades de Pointes
- Ventricular Fibrillation
- Cardiac Arrest
- Gastrointestinal
- Neurologic
VI. Labs
- Benzonatate Levels are not typically available and unlikely to be useful (rapidly metabolized)
- See Unknown Ingestion
- Includes evaluation and management including general toxicology labs
VII. Management
-
Gastric Decontamination
- Not recommended unless polysubstance ingestion
- Benzonatate is rapidly absorbed
- Seizures
- Cardiovascular instability (Hypotension, dysrythmia)
- Hypotension with Wide QRS
- Sodium Bicarbonate 1-2 mEq/kg boluses until QRS narrows
- Other measures
- Intralipid (20% Lipid Emulsion) 1.5 ml/kg
- ECMO
- Hypotension with Wide QRS
- Disposition
- Admit all symptomatic patients
- Observe for 4-6 hours after intentional ingestion or pediatric ingestion >1 capsule
VIII. References
- Tomaszewski (2021) Crit Dec Emerg Med 35(7):32
- Bishop-Freeman (2017) J Anal Toxicol 41:461-3 [PubMed]