Benzonatate

What it is

Benzonatate is a synthetic prescription cough medicine, a polyethylene-glycol ester of para-aminobenzoic acid that is chemically related to the local anaesthetics procaine and tetracaine. It is supplied as liquid-filled capsules (100 mg and 200 mg in the United States) that are meant to be swallowed whole, because releasing the liquid in the mouth numbs the mouth and throat. It is not a narcotic and is not related to codeine or dextromethorphan.

What the research says

The evidence base for benzonatate is thin and old. A 2023 systematic review of the entire literature from 1956 to 2022 found 37 articles, only 5 of them experimental, with high risk of bias throughout, and concluded that the drug's approval rests on evidence that would not pass current regulatory review. Mechanistically it is described as numbing stretch receptors in the airways and lungs so that the cough reflex is less easily triggered. What is firmly documented is the harm side: overdose, including accidental ingestion of a small number of capsules by young children, has caused seizures and cardiac arrest within minutes and has been fatal.

Evidence grade: Limited evidence.

How it works

Drug class: Non-narcotic peripherally acting antitussive; a polyethylene-glycol ester of para-aminobenzoic acid, chemically related to the ester local anaesthetics (procaine, tetracaine)

Benzonatate is described as acting on the airway itself rather than on the brain: it numbs (anaesthetises) the stretch receptors in the breathing passages, lungs and the lining of the lung, so those receptors fire less and the cough reflex is harder to trigger. The label states it starts working in 15 to 20 minutes and lasts 3 to 8 hours. This description comes from the manufacturer's prescribing information, not from a modern mechanistic study. (Source 1)

What it is used for

• This is the only approved use. A 2023 systematic review searching four databases back to 1956 found only 37 studies, 5 of them experimental, all judged at high risk of bias, and said the evidence base has substantial limitations. No modern randomised placebo-controlled outcome trial was identified in the sources reached. Evidence: limited. (Source 2)
• Benzonatate is prescribed to children even though safety and effectiveness below age 10 have never been established, and accidental ingestion has killed children. US poison centres logged 4,689 paediatric benzonatate exposures between 2010 and 2018, most of them unintentional and most in children aged 0 to 5. Evidence: not-supported. (Source 3)
• Not a human use. A 2023 rat study showed benzonatate does produce sensory and motor nerve blockade when injected, but also caused significant inflammation and muscle damage even at low concentrations. This is animal work only and does not support any human use. Evidence: not-supported. (Source 4)

Interactions

• Other prescribed medicines (central nervous system effects) (case reports): Cases of strange behaviour, mental confusion and seeing things that are not there have been reported in people taking benzonatate together with other prescribed drugs. The label does not name which drugs, and no interaction study is cited. (Source 3)
• Para-aminobenzoic-acid ester local anaesthetics (procaine, tetracaine) (theoretical): Benzonatate is chemically in the same family as procaine and tetracaine. The label links its nervous-system side effects either to a previous sensitivity to those related anaesthetics or to interaction with another medicine being taken at the same time. This is a chemical-class inference, not a measured interaction. (Source 5)
• Central nervous system stimulants (in overdose management) (label): In benzonatate overdose the label instructs clinicians not to give CNS stimulants, because the pattern of poisoning is early stimulation followed by deep depression of the nervous system. (Source 6)

Stopping it

• No withdrawal syndrome, rebound or taper is described for benzonatate in the material we reached. The label frames it as an as-needed cough medicine taken up to three times a day, and the patient information tells people to skip a missed dose rather than double up, which is consistent with stopping it outright when the cough settles. (Source 7)
• The only stopping guidance in the label concerns the mouth-numbing effect: if the tongue, mouth, throat or face goes numb or tingly, people are told not to eat or drink until it has passed and to seek medical attention if it worsens or persists. (Source 8)

What goes wrong

In an FDA review of adverse-event reports from 1969 to 2010, 20 of 31 reported benzonatate overdoses were fatal, and five of those deaths were accidental ingestions by children aged 2 years or younger. (Source 9)

• Case series, Low certainty.
• Size: 31 overdose cases in the FDA AERS database; 12 emergency department visits in NEISS-CADES.
• Who: any patient with a reported benzonatate adverse event, 1969-2010 (AERS) and 2004-2009 (NEISS-CADES)
• How long: 41 years of spontaneous reporting.
• Result: 20/31 AERS overdose cases fatal; 5 of those fatalities were accidental ingestions in children aged 2 years and younger; 12 emergency department visits for accidental ingestion in children aged 1-3 years; symptoms began in some patients within 15 minutes.
• Funding: independent (US Food and Drug Administration authors)

Of 31 overdose cases involving benzonatate reported in the AERS database, 20 had a fatal outcome, and five of these fatalities occurred from accidental ingestions in children 2 years of age and younger.

A 2021 systematic review of severe benzonatate poisonings found cardiac arrest in 29 of 36 cases and seizures in 24, with only 5 patients surviving neurologically intact. (Source 10)

• Systematic review, Low certainty.
• Size: 36 cases (17 from the US National Poison Data System 2000-2018, 19 from published reports)
• Who: patients with severe benzonatate poisoning; median age 17 years (IQR 11-29); 22 of 36 female; 28 of 36 self-harm ingestions.
• How long: onset of toxicity rapid, under 5 minutes in 9 cases.
• Result: Cardiac arrest 29/36; seizures 24/36; dysrhythmias 24/36; intubation 26; CPR 28; vasopressors 20; return of spontaneous circulation 23/28, but only 5 survived with a good neurologic outcome.
• Funding: not stated.

Most common symptoms included cardiac arrest (29), seizures (24), and dysrhythmias (24).

The same review concluded that benzonatate overdose can cause rapid, severe toxicity and that even patients who are resuscitated often end up with poor outcomes. (Source 11)

• Systematic review, Low certainty.
• Size: 36 cases.
• Who: severe benzonatate poisoning.
• How long: not applicable.
• Result: Qualitative: rapid onset, short duration of direct toxicity, frequent neurologic devastation.
• Funding: not stated.

Duration of directly toxic effects is short, but dramatic with neurologic devastation and resuscitated patients often still have a poor outcome.

US poison centres recorded 4,689 paediatric benzonatate exposures between 2010 and 2018, most unintentional and concentrated in children aged 0 to 5, although the proportion with serious effects was low. (Source 12)

• Survey study, Low certainty.
• Size: 4,689 paediatric exposure cases; 3,727 single-substance.
• Who: US children reported to poison control centres, 2010-2018.
• How long: 9 years of surveillance.
• Result: 3,727/4,689 (80%) single-substance; 3,590 (77%) unintentional; 2,718 of those (83%) in children aged 0-5; 59 misuse/abuse cases (61%) in children aged 10-16; proportion of cases with serious adverse effects described as low.
• Funding: not stated.

Limit of this finding: The paper's percentages do not all match the numbers they sit beside. 3,727 of 4,689 is 80 percent, which is right. But '3,590 cases (77%)' is 77 percent of all 4,689 cases, not of the 3,727 that 'of these' points at, and 2,718 children aged 0 to 5 described as 83 percent matches neither figure (it is 76 percent of 3,590 and 73 percent of 3,727). Take the counts as reported and the percentages as unreliable. These are also calls to poison centres, not diagnosed poisonings, and the prescribing trend in the first sentence comes from a separate prescription database with no denominator given.

Among the 4689 pediatric benzonatate exposure cases reported to US poison control centers from 2010 to 2018, 3727 cases (80%) were for single-substance exposures. Of these, 3590 cases (77%) were unintentional exposures and most involved children 0 to 5 years old (2718 cases, 83%).

The label records severe hypersensitivity reactions including bronchospasm, laryngospasm and cardiovascular collapse, linked to sucking or chewing the capsule rather than swallowing it. (Source 3)

• Official position, Low certainty.
• Size: not quantified (spontaneous postmarketing reports)
• Who: patients taking benzonatate.
• How long: not applicable.
• Result: No rates given; severe reactions have required vasopressors and supportive measures.
• Funding: industry-funded (manufacturer label)

Severe hypersensitivity reactions (including bronchospasm, laryngospasm and cardiovascular collapse) have been reported which are possibly related to local anesthesia from sucking or chewing the capsule instead of swallowing it.

The label lists sedation, headache, dizziness, mental confusion, visual hallucinations, constipation, nausea, itching and rash as possible reactions, with no frequencies attached and no placebo comparison. (Source 13)

• Official position, Very low certainty.
• Size: not stated.
• Who: patients taking benzonatate.
• How long: not stated.
• Result: No numerical rates are given anywhere in the label's adverse reactions section, and there is no drug-versus-placebo comparison.
• Funding: industry-funded (manufacturer label)

Limit of this finding: The run-together words in the quotation - 'CNS:sedation', 'GI:constipation' - are in the electronic label itself, where the bold category headings abut the text with no space. They need a space inserted before display; nothing has been added or removed from the wording.

CNS:sedation; headache; dizziness; mental confusion; visual hallucinations. GI:constipation; nausea; GI upset.

This is animal work, not a human study: benzonatate injected at the sciatic nerve of rats produced nerve blockade but also caused significant inflammation and muscle damage even at low concentrations. (Source 14)

• Animal study, Low certainty.
• Size: Sprague-Dawley rats (number not stated in the abstract)
• Who: Sprague-Dawley rats, benzonatate injected at the sciatic nerve.
• How long: single injection with histology.
• Result: Concentration-dependent sensory and motor nerve blockade; significant inflammation and myotoxicity on histology even at subtherapeutic concentrations.
• Funding: not stated.

Limit of this finding: The quoted sentence does not say so, but every result in this paper comes from rats. The paper's Methods section reads 'Benzonatate was injected at the sciatic nerve of Sprague-Dawley rats.' It is also about injecting the drug next to a nerve, which is not how benzonatate is taken; it says nothing about swallowing a capsule.

Histologic assessment showed significant inflammation and myotoxicity from benzonatate injection, even at low concentrations.

What the evidence supports

The manufacturer's prescribing information states an onset of 15 to 20 minutes and a duration of 3 to 8 hours, which is a regulatory position rather than trial evidence. (Source 1)

• Official position, Very low certainty.
• Size: not stated.
• Who: adults and children over 10 years.
• How long: single dose.
• Result: Onset within 15 to 20 minutes; effect lasting 3 to 8 hours; no inhibitory effect on the respiratory centre at labelled doses.
• Funding: industry-funded (manufacturer label)

It begins to act within 15 to 20 minutes and its effect lasts for 3 to 8 hours. Benzonatate has no inhibitory effect on the respiratory center in recommended dosage.

What the evidence does not support

The whole published literature on benzonatate's effectiveness consists of 37 articles, only 5 of them experimental, and the reviewers judged the body of evidence at high risk of bias with very small study populations. (Source 2)

• Systematic review, Very low certainty.
• Size: 37 articles (21 cohort studies, 5 experimental studies, 11 case studies and series)
• Who: any population in original research on benzonatate effectiveness, tolerability or safety.
• How long: literature from January 1956 through August 2022.
• Result: No pooled effect estimate was possible; the review reports 37 included articles with quality assessment flagging high degrees of bias related to limited sample size, data collection, generalizability and study design.
• Funding: not stated.

The selection process resulted in 37 articles consisting of 21 cohort studies, 5 experimental studies, and 11 case studies and series. Initial clinical studies exploring potential therapeutic benefits collected data from very small populations and limited clinical settings.

The same systematic review found substantial limitations in the evidence for both safety and clinical effectiveness and called for large observational studies or randomised trials. (Source 15)

• Systematic review, Very low certainty.
• Size: 37 articles.
• Who: as above.
• How long: 1956-2022.
• Result: No effect size; the review's own verdict is that existing evidence has substantial limitations.
• Funding: not stated.

This review reveals substantial limitations within existing evidence pertaining to the safety and clinical effectiveness of benzonatate and thus, a need for large observational studies or randomized trials to better characterize its role and value in modern medical practice.

The reviewers stated that benzonatate's approval rests on evidence that would not meet today's regulatory standard. (Source 16)

• Systematic review, Very low certainty.
• Size: 37 articles.
• Who: as above.
• How long: 1956-2022.
• Result: Qualitative verdict only.
• Funding: not stated.

Rising safety concerns should bring closer scrutiny upon the prescription of benzonatate whose approval is founded upon evidence that would not stand up to current regulatory review.

A 2021 review of antitussive medicines in young children states that cough and cold remedies are sold in enormous volume despite a lack of evidence that they work. (Source 17)

• Expert review, not systematic, Low certainty.
• Size: not stated (narrative review of OTC and prescription antitussives)
• Who: young children with acute cough.
• How long: not applicable.
• Result: No effect size reported; the review's position is that evidence of efficacy is lacking and that OTC antitussives should not be routinely used under age 2.
• Funding: not stated.

Limit of this finding: This is an expert review article, not a study. It reports no effect estimate of its own, and the recommendation it states against routine use of over-the-counter cough medicines in children under 2 is the authors' summary rather than a named regulator's or professional body's formal position.

Cough and cold remedies generate billions of dollars in annual sales in the United States, despite a lack of evidence of their efficacy and multiple warnings by the US Food and Drug Administration.

Where the research disagrees

Whether benzonatate should still be prescribed at all, given how weak the efficacy evidence is and how lethal overdose can be

• Authors of the 2023 Annals of Pharmacotherapy systematic review, systematic-review: Rising safety concerns should bring closer scrutiny upon the prescription of benzonatate whose approval is founded upon evidence that would not stand up to current regulatory review. (Source 16)
• FDA authors of the 2013 Pharmacotherapy overdose analysis, case-series: Although benzonatate has a long history of safe use, accumulating cases of fatal overdose, especially in children, prompted the FDA to notify health care professionals about the risks of benzonatate overdose. (Source 18)
• Authors of the 2022 Pediatrics exposure study, cross-sectional: Rational prescribing and improved provider and caregiver awareness of benzonatate toxic effects may reduce risks associated with benzonatate exposure. (Source 19)

How much

• Reference intake: There is no reference intake for a prescription drug. Dose is set by the prescriber. As a position, the US label states the usual dose for adults and children over 10 years is one 100 mg or 200 mg capsule three times a day as needed for cough, and that capsules must be swallowed whole (Time Cap Laboratories label, SPL effective 7 September 2026). (Source 7)
• Upper limit: No tolerable upper intake level exists for a drug. As a position, the label's patient information sets a ceiling of 200 mg in a single dose and 600 mg in a day (Time Cap Laboratories label, SPL effective 7 September 2026). (Source 8)
• Studied: The sources reached did not yield extractable trial doses: the 2023 systematic review searched PubMed, Embase, the Cochrane Library and Scopus from January 1956 to August 2022 and found only 5 experimental studies, in very small populations, at high risk of bias. (Source 20)

A common belief, and what the research shows

The belief: Benzonatate is a well-proven cough medicine, and because it is not a narcotic it is a safe choice to have in the house.

What the research shows: Neither half of that holds up. On effectiveness, the 2023 systematic review of everything published from 1956 to 2022 found that "The selection process resulted in 37 articles consisting of 21 cohort studies, 5 experimental studies, and 11 case studies and series. Initial clinical studies exploring potential therapeutic benefits collected data from very small populations and limited clinical settings." On safety, being non-narcotic does not make it benign in overdose: the label states "Accidental ingestion of benzonatate resulting in death has been reported in children below age 10. Signs and symptoms of overdose have been reported within 15-20 minutes and death has been reported within one hour of ingestion."

Questions and answers

What is it?

Benzonatate is a prescription-only cough medicine, not a vitamin, mineral or food substance. Chemically it is a long polyethylene-glycol chain attached to a para-aminobenzoic acid ester, which puts it in the same family as the numbing drugs procaine and tetracaine. In the United States it comes as liquid-filled 100 mg and 200 mg capsules. It is non-narcotic, so it is not related to codeine. (Source 21)

What does it do in the body?

It is described as working on the airway rather than the brain. It numbs the stretch receptors in the breathing passages, lungs and the lining of the lung, so those receptors fire less and the cough reflex is harder to set off. The manufacturer's information puts onset at 15 to 20 minutes and duration at 3 to 8 hours. This account comes from the label, not from a modern mechanistic study, and no randomised placebo-controlled outcome trial was found in the sources we reached. (Source 1)

Is it good or bad for you?

The honest answer is that the benefit is poorly documented and the harm in overdose is well documented. A 2023 systematic review covering 1956 to 2022 found the evidence for both effectiveness and safety has substantial limitations and called for proper trials. Against that, 20 of 31 overdose cases reported to the FDA were fatal, and the reported overdose cases show seizures and cardiac arrest beginning within minutes. At labelled doses in adults who swallow the capsule whole, serious reactions appear uncommon, but the margin for error is small, especially around children. (Source 15)

How do you get more of it?

Does not apply in the usual sense. Benzonatate is a manufactured medicine, not a nutrient, so there is no way to get more of it from food or lifestyle. The only source is a prescription, at the dose the prescriber sets; the label's stated usual range for adults and children over 10 is one 100 mg or 200 mg capsule three times a day as needed for cough, with capsules swallowed whole. (Source 7)

If it is harmful, what reduces it?

Benzonatate is cleared by the body on its own once dosing stops, and no taper is described. In overdose it is a medical emergency: the label says to seek medical attention immediately, empty the stomach and give large amounts of activated charcoal, treat seizures with a short-acting intravenous barbiturate, and specifically not to give stimulants. (Source 6)

Why might someone be low in it or missing it?

Does not apply. Benzonatate is not something the body makes or needs, so nobody can be deficient in it. The only reason someone would not have it in their system is that it has not been prescribed, or the prescription has finished. It is a synthetic chemical manufactured into capsules. (Source 21)

Which whole foods contain it or feed it?

None. No whole food contains benzonatate and nothing in the diet feeds or boosts it; it is a synthetic ester manufactured as a drug. The sources we reached document no food or drink that interacts with it either, although people are told not to eat or drink while the mouth is numb after a capsule has been chewed or dissolved by mistake. (Source 8)

What happens if you do not have it?

Nothing happens physiologically, because benzonatate is not a substance the body requires. Someone who does not take it simply has an untreated cough. How much is lost by not taking it is genuinely unclear: the 2023 systematic review found the entire effectiveness literature amounted to 37 articles, only 5 of them experimental, in very small populations and at high risk of bias. (Source 2)

How can you test for it?

There is no clinical blood or urine test for benzonatate and no monitoring test is described. The 2023 systematic review, which searched PubMed, Embase, the Cochrane Library and Scopus from 1956 to 2022, found that safety is judged from overdose and misuse cases rather than from any laboratory measure. (Source 2)

We searched: Europe PMC searches for benzonatate plus monitoring, assay, blood level, therapeutic drug monitoring and systematic review; the 2023 Annals of Pharmacotherapy systematic review's four-database search (PubMed, Embase, Cochrane Library, Scopus, 1956-2022); the full Time Cap Laboratories benzonatate SPL, which contains no monitoring or laboratory-test section

References

1. DailyMed / US Food and Drug Administration (Time Cap Laboratories, Inc); SPL effective 7 September 2026 (version 1). BENZONATATE 100 MG (BENZONATATE) CAPSULE, LIQUID FILLED / BENZONATATE 200 MG (BENZONATATE) CAPSULE, LIQUID FILLED - FDA prescribing information (Structured Product Label). 2026. Read the source
2. The Annals of pharmacotherapy. Benzonatate Safety and Effectiveness: A Systematic Review of the Literature.. 2023. PMID 36688284, DOI 10.1177/10600280221135750. Read the source
3. DailyMed / US Food and Drug Administration (Time Cap Laboratories, Inc); SPL effective 7 September 2026 (version 1). BENZONATATE 100 MG (BENZONATATE) CAPSULE, LIQUID FILLED / BENZONATATE 200 MG (BENZONATATE) CAPSULE, LIQUID FILLED - FDA prescribing information (Structured Product Label). 2026. Read the source
4. PloS one. Benzonatate as a local anesthetic.. 2023. PMID 37043508, DOI 10.1371/journal.pone.0284401. Read the source
5. DailyMed / US Food and Drug Administration (Time Cap Laboratories, Inc); SPL effective 7 September 2026 (version 1). BENZONATATE 100 MG (BENZONATATE) CAPSULE, LIQUID FILLED / BENZONATATE 200 MG (BENZONATATE) CAPSULE, LIQUID FILLED - FDA prescribing information (Structured Product Label). 2026. Read the source
6. DailyMed / US Food and Drug Administration (Time Cap Laboratories, Inc); SPL effective 7 September 2026 (version 1). BENZONATATE 100 MG (BENZONATATE) CAPSULE, LIQUID FILLED / BENZONATATE 200 MG (BENZONATATE) CAPSULE, LIQUID FILLED - FDA prescribing information (Structured Product Label). 2026. Read the source
7. DailyMed / US Food and Drug Administration (Time Cap Laboratories, Inc); SPL effective 7 September 2026 (version 1). BENZONATATE 100 MG (BENZONATATE) CAPSULE, LIQUID FILLED / BENZONATATE 200 MG (BENZONATATE) CAPSULE, LIQUID FILLED - FDA prescribing information (Structured Product Label). 2026. Read the source
8. DailyMed / US Food and Drug Administration (Time Cap Laboratories, Inc); SPL effective 7 September 2026 (version 1). BENZONATATE 100 MG (BENZONATATE) CAPSULE, LIQUID FILLED / BENZONATATE 200 MG (BENZONATATE) CAPSULE, LIQUID FILLED - FDA prescribing information (Structured Product Label). 2026. Read the source
9. Pharmacotherapy. Analysis of benzonatate overdoses among adults and children from 1969-2010 by the United States Food and Drug Administration.. 2013. PMID 23307543, DOI 10.1002/phar.1153. Read the source
10. Human & experimental toxicology. A description of the clinical course of severe benzonatate poisonings reported in the literature and to NPDS: A systematic review supplemented with NPDS cases.. 2021. PMID 34219543, DOI 10.1177/09603271211030560. Read the source
11. Human & experimental toxicology. A description of the clinical course of severe benzonatate poisonings reported in the literature and to NPDS: A systematic review supplemented with NPDS cases.. 2021. PMID 34219543, DOI 10.1177/09603271211030560. Read the source
12. Pediatrics. Benzonatate Exposure Trends and Adverse Events.. 2022. PMID 36377394, DOI 10.1542/peds.2022-057779. Read the source
13. DailyMed / US Food and Drug Administration (Time Cap Laboratories, Inc); SPL effective 7 September 2026 (version 1). BENZONATATE 100 MG (BENZONATATE) CAPSULE, LIQUID FILLED / BENZONATATE 200 MG (BENZONATATE) CAPSULE, LIQUID FILLED - FDA prescribing information (Structured Product Label). 2026. Read the source
14. PloS one. Benzonatate as a local anesthetic.. 2023. PMID 37043508, DOI 10.1371/journal.pone.0284401. Read the source
15. The Annals of pharmacotherapy. Benzonatate Safety and Effectiveness: A Systematic Review of the Literature.. 2023. PMID 36688284, DOI 10.1177/10600280221135750. Read the source
16. The Annals of pharmacotherapy. Benzonatate Safety and Effectiveness: A Systematic Review of the Literature.. 2023. PMID 36688284, DOI 10.1177/10600280221135750. Read the source
17. Journal of the American College of Emergency Physicians open. Use of antitussive medications in acute cough in young children.. 2021. PMID 34179887, DOI 10.1002/emp2.12467. Read the source
18. Pharmacotherapy. Analysis of benzonatate overdoses among adults and children from 1969-2010 by the United States Food and Drug Administration.. 2013. PMID 23307543, DOI 10.1002/phar.1153. Read the source
19. Pediatrics. Benzonatate Exposure Trends and Adverse Events.. 2022. PMID 36377394, DOI 10.1542/peds.2022-057779. Read the source
20. The Annals of pharmacotherapy. Benzonatate Safety and Effectiveness: A Systematic Review of the Literature.. 2023. PMID 36688284, DOI 10.1177/10600280221135750. Read the source
21. DailyMed / US Food and Drug Administration (Time Cap Laboratories, Inc); SPL effective 7 September 2026 (version 1). BENZONATATE 100 MG (BENZONATATE) CAPSULE, LIQUID FILLED / BENZONATATE 200 MG (BENZONATATE) CAPSULE, LIQUID FILLED - FDA prescribing information (Structured Product Label). 2026. Read the source