Key takeaways

Benzonatate is a prescription medication used to relieve cough in adults and children aged 10 years and older, and can cause side effects such as sedation, headache, and dizziness.
It is important to swallow benzonatate capsules whole to avoid releasing the medication in the mouth, which can lead to numbness and potentially life-threatening constriction of airways.
Benzonatate should be used with caution, stored properly to prevent accidental ingestion by children, and not combined with certain types of drugs due to potential interactions.
To minimize side effects, take benzonatate only as directed, avoid biting or chewing the capsule, and consult a doctor if coughing persists or if experiencing severe central nervous system impairments such as dizziness, confusion, or hallucinations.

Benzonatate is a generic non-opioid medication used for the relief of symptomatic or chronic cough in adults and children 10 years of age and older. Available as a generic medication or under the brand name Tessalon Perles, benzonatate is taken as a capsule three times a day as needed.

Benzonatate, which is chemically similar to topical anesthetics such as procaine and tetracaine, numbs receptors in the lungs that initiate the cough reflex. Besides treating cough, benzonatate is sometimes used off-label—applied as an anesthetic to the surfaces of the mouth and throat by a healthcare professional before intubation or an endoscopy. It is also used off-label to treat stubborn or unstoppable hiccups.

Like all medications, benzonatate can cause problems, so this article will review side effects, restrictions, drug interactions, and how to take the drug properly and safely.

RELATED: Learn more about benzonatate

Common side effects of benzonatate

The incidence of side effects when taking benzonatate is not known. The Food and Drug Administration (FDA) lists the most common side effects of benzonatate as:

Sedation
Headache
Dizziness
Itching
Skin rash
Nausea
Stomach upset
Constipation
Confusion
Visual hallucinations
Numbness in the chest
Nasal congestion (stuffy nose)
Eye irritation or burning
Chills

Serious side effects of benzonatate

Benzonatate’s most severe side effects are allergic reactions, which may be caused by biting, chewing, or sucking on the capsule. Benzonatate should always be swallowed whole so the medicine is not released into the mouth or the back of the throat.

Severe hypersensitivity reactions include:

Anaphylaxis, an allergic reaction that causes nausea, vomiting, skin rash, trouble breathing, and a rapid and potentially lethal drop in blood pressure (called shock)
Bronchospasm, or constricting of the lung’s airways
Laryngospasm, or a constriction of the vocal cords, making speaking or breathing difficult

Allergic reactions are rare but can be serious or life-threatening, so if you have any of the symptoms listed above, seek emergency medical treatment right away.

How long do benzonatate side effects last?

Many of the side effects of benzonatate will occur rapidly (within 15 minutes) after taking the drug, such as itching, chills, and eye irritation. Central nervous system (CNS) problems, such as headache, confusion, visual hallucinations, and dizziness, occur fairly early (within an hour) after taking a dose of benzonatate. These rapid or early side effects generally fade as the drug wears off in three to eight hours. Other common side effects, particularly digestive system problems, are delayed and may last longer. Severe allergic reactions require emergency medical treatment and persist for several hours or days.

Benzonatate contraindications & warnings

Benzonatate can cause problems in some people. More importantly, benzonatate is potentially lethal when taken incorrectly or given to children. This drug must be taken as prescribed and stored properly. Anyone taking benzonatate—even for a few days—should carefully learn the possible risks.

Abuse and dependence

Benzonatate does not cause dependence or withdrawal symptoms. It is not a drug with a known history of abuse or misuse. This distinguishes benzonatate from opioid or opioid-like cough drugs, like codeine or dextromethorphan.

Overdose

Benzonatate is potentially lethal at high doses. Death from swelling in the brain (cerebral edema) or a heart attack can occur within one hour after taking too much benzonatate.

Symptoms of overdose such as tremors and restlessness usually occur within 10–15 minutes of an overdose. Severe symptoms of benzonatate overdose can occur within the first hour and include:

Convulsions
Slow heart rate
Weak pulse
Slow breathing
Fainting
Coma

If an overdose is suspected, call a poison control center and get immediate medical attention. There is no antidote. Treatment will consist of emptying the stomach, monitoring, and support.

There are reports of death in young children caused by a benzonatate overdose. Benzonatate gel capsules look like candy, so children are particularly at risk for accidental overdose. Even a normal dose could harm a small child. For these reasons, benzonatate should always be stored in a sealed, child-resistant container out of reach of any children.

Restrictions

Benzonatate can only be used by people 10 years of age or older. It can not be used by anyone under the age of 10 years. The medication, however, may not be right for everyone.

Benzonatate is not given to people with hypersensitivity to PABA anesthetic medications or who cannot swallow the capsule. If the capsule is not properly swallowed, the medication can numb the mouth, create a choking hazard, and possibly cause life-threatening constriction of the larynx and airways.

Benzonatate has not been determined as safe to take while pregnant.Women should tell the doctor or healthcare provider about any pregnancy or pregnancy plans before taking this medication.

It is not known if benzonatate passes into breast milk or affects lactation. The American Academy of Pediatrics (AAP) has not issued a recommendation regarding benzonatate and breastfeeding. A doctor or other healthcare provider can provide medical advice to nursing mothers about the safety of benzonatate as well as information about alternative prescription or over-the-counter antitussives. Because of the lack of information on benzonatate and breastfeeding, a different medication may be preferred.

Benzonatate interactions

The FDA drug information for benzonatate products does not list any significant drug interactions. However, the Prescriber’s Digital Reference (PDR) advises that benzonatate not be used with certain types of drugs including:

Local anesthetics: Lidocaine, prilocaine, and similar drugs work like benzonatate by numbing the nerves. All these drugs, including benzonatate, have potential toxic effects, so doctors and other healthcare professionals are advised to use caution when combining them.
Monoamine oxidase inhibitors: MAO inhibitors are a small class of drugs that include some antidepressants (phenelzine, isocarboxazid, tranylcypromine), an antibiotic (linezolid), certain Parkinson’s disease medications (rasagiline and selegiline), and methylene blue, used to treat urinary infections or as a contrast dye for X-rays or surgery. Combining them with benzonatate may cause low blood pressure or worsen side effects involving the central nervous system.
Sedatives, benzodiazepines, opioids, muscle relaxants, antihistamines, and alcohol: The sedative effects of drugs that depress the central nervous system may be enhanced when combined with benzonatate.

These drug interactions are largely theoretical, that is, there are no published reports of benzonatate reactions with any other type of drug. The best advice is to discuss all the medications you take, including prescription, OTC, and vitamins or supplements, with your doctor. If you take a drug that may interact with benzonatate, monitor side effects. If there are problems, consult your doctor for medical advice or seek emergency treatment if required..

How to avoid benzonatate side effects

There are no published statistics on what percentage of people experience benzonatate side effects. Although the drug is usually only prescribed for a few days, side effects typically appear within minutes or hours of taking the medicine, rather than being caused by long-term use.

A few tips can help people taking benzonatate to avoid or minimize side effects:

1. Tell a doctor about all medical conditions and medications

There are only a few instances where a doctor or other healthcare professional will not prescribe benzonatate, but make sure the doctor knows about all medical conditions and medications, especially:

Allergies to topical anesthetics like lidocaine, procaine, or tetracaine (found in certain insect bite, numbing, and sunburn creams)
Difficulty swallowing
Pregnancy or breastfeeding
Any topical anesthetics being used

2. Take benzonatate as directed

Follow all the directions on the prescription label or provided by a healthcare professional. Follow the dosing schedule and do not take more or less of this medication than instructed.

3. Do not bite, chew, or suck on the capsule

Swallow the capsule whole. Do not bite, chew, or suck on the capsule. If you do, the medicine will be released and will instantly numb the mouth and throat. The numbness can make swallowing difficult. Eating or drinking with a numbed mouth and throat could cause choking.

4. Do not eat or drink if the mouth goes numb

If the mouth or throat are numbed by the medicine, do not drink or eat until the numbness goes away. Eating or drinking could cause choking. Wait until the numbness passes. If numbness persists for longer than a few hours, call a doctor or get medical attention.

5. Take the medicine only while coughing persists

To avoid possible side effects, only take this medicine when experiencing cough symptoms. When the cough clears up, don’t take additional doses “just to be sure.” Wait until cough symptoms reappear before taking another dose.

6. See a doctor if coughing persists for too long

Consult with your doctor if coughing persists for longer than seven days. It may be a sign of an underlying condition that should be treated instead of the cough symptoms.

7. Call a doctor if feeling dizzy, drowsy, or unusual

Benzonatate can cause central nervous problems such as dizziness, hallucinations, confusion, or extreme drowsiness. Call a doctor or other healthcare professional if benzonatate is causing serious CNS impairment. Medical help may also be necessary if experiencing side effects like chills or chest numbness.

8. Be cautious about driving or other risky activities

Benzonatate can cause central nervous system (CNS) problems like sleepiness and dizziness or, worse, hallucinations or mental confusion. The likelihood of experiencing these side effects is not known. Try to avoid driving or other risky activities until the effects of the medicine are well-known. If the medication causes central nervous system problems, avoid any risky activities while taking the medicine.

9. Keep benzonatate out of the reach of children

Young children have died from accidentally consuming benzonatate. Although all OTC and prescription drugs should be kept out of the reach of children, it is especially important to ensure that benzonatate is always stored in a sealed, child-resistant container out of the reach of children.

Discard any unused benzonatate. Do not save it for future use. Here is how to discard benzonatate:

Take the pills out of the prescription vial
Mix them with an unappealing substance like coffee grounds or kitty litter (this will make it less appealing to children or pets).
Place the medication in a sealable bag or empty can with a tight lid, and place in household trash.

10. Store benzonatate properly

All medicines come with storage instructions. While some people read and follow these instructions, others do not. For benzonatate capsules, it’s very important that they are stored in a sealed container at room temperature (between 68˚and 77˚F) away from heat, light, and humidity. If the gel capsules begin to dissolve in excess humidity, melt in the heat, or become brittle in temperatures below freezing, they are more likely to release the medicine in the mouth, causing numbness, difficulty swallowing, and possible severe adverse effects.

Resources:

Benzonatate, Epocrates
Benzonatate compound summary, U.S. National Library of Medicine
Benzonatate drug summary, Prescribers Digital Reference (PDR)
Benzonatate prescribing information, U.S. National Library of Medicine
FDA Drug Safety Communication: Death resulting from overdose after accidental ingestion of Tessalon (benzonatate) by children under 10 years of age, Food and Drug Administration (FDA)
Tessalon prescribing information, U.S. National Library of Medicine