11 Benzonatate Side Effects You Should Know About

If you have a cough and have already tried over-the-counter (OTC) cough medications, one prescription-only option is benzonatate (Tessalon). Benzonatate is a cough suppressant. It lowers your urge to cough by temporarily numbing certain areas in your lungs and airways.

Benzonatate is generally well tolerated, but you may still experience side effects while taking it. Below, we review what to expect when you’re taking benzonatate and what to do if you experience serious side effects.

Benzonatate side effects at a glance

Like all medications, benzonatate has the potential to cause side effects. But in general, the medication is well tolerated. Taking benzonatate as directed can help prevent or minimize side effects.

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Common benzonatate side effects include:

• Drowsiness

• Dizziness

• Headaches

• Constipation

• Nausea

• Upset stomach

• Feeling cold or chilly

• Stuffy nose

Rare but serious benzonatate side effects include:

• Confusion

• Visual hallucinations (seeing things that others don’t)

• Numbness of the mouth, throat, or chest

• Trouble swallowing

• Burning in the eyes

• Severe allergic reactions

• Death in children younger than 10 years old

Keep in mind that this list doesn’t include all possible benzonatate side effects. Below, you’ll find detailed information about 11 benzonatate side effects and how to manage them.

1. Drowsiness

Drowsiness is a mild benzonatate side effect. It should be less noticeable than the sleepiness caused by prescription cough syrups that contain codeine. But it’s still important to be aware that benzonatate can make you feel sleepy.

When you first start taking benzonatate, it’s a good idea to avoid driving and other activities that require you to be alert. Wait to see how the medication affects you before resuming these activities. 

EXPERT PICKS: WHAT TO READ NEXT

• How to take benzonatate: Taking the benzonatate dosage recommended by your prescriber can help limit side effects.

• Avoiding interactions: Pharmacists review notable benzonatate interactions and how to manage them.

• Is your cough serious? Here’s when to see a healthcare professional for a cough.

Avoid combining benzonatate with other medications and substances that cause drowsiness, such as opioids, benzodiazepines, and alcohol. You may also want to forgo taking medications that contain older antihistamines, such as doxylamine (Unisom SleepTabs) and diphenhydramine (Benadryl, ZzzQuil). These can also cause drowsiness.

If you’re only taking benzonatate once a day, try taking it at bedtime. This can help limit coughing at night and drowsiness during the day.

If you’re taking benzonatate more than once a day and drowsiness is interfering with your daily activities, talk to your prescriber. The maximum recommended benzonatate dosage is 600 mg total per day, so you may need a lower dosage or a different medication to manage your cough.

2. Dizziness

Another mild benzonatate side effect is dizziness. If you have any health conditions that cause dizziness, benzonatate may worsen this symptom.

If you experience dizziness, find a safe place to sit or lie down. This can help prevent you from falling if you lose your balance. Staying hydrated and eating regularly can also help limit or prevent dizziness.

Dizziness from benzonatate usually stops once the medication wears off. But if you notice excessive or persistent dizziness, stop taking benzonatate and contact your prescriber.

3. Headaches

Headaches are another mild benzonatate side effect. But keep in mind that headaches can also be a symptom of illnesses that commonly cause coughing, such as the flu. So if you’re experiencing headaches, it’s possible they’re not related to taking benzonatate.

Regardless of the cause, there are some home remedies you can try for headache relief:

• Drink plenty of water and other fluids.

• If you can, exercise or try to add more movement into your daily routine.

• Take steps to optimize your sleep routine so you get adequate rest.

• Try to lower your stress levels with calming activities or breathing exercises.

You can also ask a healthcare professional about taking an OTC pain reliever, like ibuprofen (Advil, Motrin) or acetaminophen (Tylenol). If your headaches are severe or don't improve with these tips, talk to a healthcare professional about next steps.

4. Constipation

Constipation is another potential benzonatate side effect. Like the side effects discussed above, constipation related to benzonatate typically only lasts while you’re taking the medication.

To relieve constipation at home, try increasing your daily consumption of fluids and fiber. If this doesn't work, ask a healthcare professional about OTC medications for constipation. They may recommend trying a laxative or stool softener.

As with other side effects, check in with a healthcare professional if you have constipation that doesn’t improve after a few days. And if it’s severe or painful at any point, it’s best to be evaluated right away.

5. Nausea

Nausea is a possible side effect of many medications, including benzonatate. But nausea related to benzonatate should be mild and resolve after you’ve finished taking the medication. Taking your doses with food may help prevent nausea from happening.

Eating smaller meals and avoiding greasy or spicy foods can help keep nausea from getting worse. You can also try eating only bland foods for a short amount of time, as these may be easier on the stomach.

If you have nausea that seems severe or causes vomiting, contact a healthcare professional. This isn’t typical of nausea related to benzonatate, so there may be another cause.

6. Stuffy nose

Nasal congestion is another mild benzonatate side effect. But it’s also a common symptom of illnesses that cause coughing, such as COVID-19. So benzonatate may not be the reason you have a stuffy nose.

Talk to a pharmacist before purchasing OTC products that are labeled for congestion relief. Some OTC cold medications interact with benzonatate, especially combination products. Your pharmacist can help recommend congestion treatments that are safe to combine with benzonatate.

Nasal spray decongestants, such as oxymetazoline (Afrin), and oral decongestants, such as pseudoephedrine (Sudafed), are typically safe to combine with benzonatate. But these products aren’t right for everyone and should only be used for a few days in a row.

If nasal decongestants aren’t an option for you, there are medication-free home remedies for congestion you can try. Using a humidifier and breathing in steam are two common strategies.

7. Hallucinations or confusion

Some medications can cause hallucinations. Hallucinations occur when a person sees, hears, or feels things that others don’t. Visual hallucinations and confusion are rare benzonatate side effects. These side effects haven’t been well studied, so we don’t know if certain people have a higher risk for them.

Tell your prescriber if you have a history of confusion or hallucinations or are taking medication for these symptoms. Get medical help right away if you notice unusual thoughts or behaviors while taking benzonatate. You’ll likely need to stop taking benzonatate and switch to a different cough medication.

8. Numbness of the mouth or throat

As mentioned earlier, benzonatate works by temporarily numbing your lungs and airways. When taken correctly, this won’t affect your ability to swallow or breathe. But if benzonatate capsules are chewed or opened, the medication can numb your mouth, throat, or chest. This can also lead to a more serious allergic reaction, which we cover below.

Always swallow benzonatate capsules whole, and try to swallow them quickly. Holding the capsules in your mouth increases the likelihood of them opening before they’re supposed to. Don’t take capsules that appear damaged.

Mild mouth or throat numbness should resolve on its own after benzonatate wears off (about 3 to 8 hours after a dose). But keep in mind that you may be at higher risk of choking if your mouth or throat is numb. Avoid eating or drinking anything until your symptoms resolve. And seek emergency medical help if you have numbness that seems severe or you’re having trouble breathing.

9. Burning in the eyes

There’s another reason not to open benzonatate capsules: The medication can be dangerous if it touches your eyes. Eye exposure can cause burning, blurred vision, and even eye damage.

Although dangerous, this benzonatate side effect can generally be avoided by properly handling the capsules. Store benzonatate at room temperature, away from light and moisture. And make sure your hands are dry before touching the capsules.

Wash your hands thoroughly if you’ve handled broken or leaking benzonatate capsules. If the medication touches your eyes, immediately flush them with water and get medical help from an eye care professional.

10. Allergic reactions

In rare cases, severe allergic reactions from benzonatate have been reported. Symptoms of an allergic reaction to benzonatate can include spasms of the lungs and throat or even sudden cardiac arrest (when the heart suddenly stops beating). Chewing or sucking on benzonatate capsules raises your risk of experiencing these potentially life-threatening symptoms.

Taking benzonatate as directed can reduce your chances of having an allergic reaction. Always swallow the capsules whole. Never open, chew, or dissolve the capsules in your mouth. And avoid taking capsules that look broken or are leaking.

11. Death in children under 10

Benzonatate should be stored out of the reach of children. There have been reports of serious benzonatate side effects in children under 10 years old. These include seizures, coma, and cardiac arrest. There have also been reports of death.

These serious side effects are related to benzonatate toxicity (overdose). Symptoms can appear quickly — within 15 to 20 minutes of accidental ingestion. Death can happen as soon as 1 hour after an overdose.

If you think a child under 10 has taken benzonatate, call 911 or go to the nearest emergency room. This type of overdose needs to be treated quickly in children to prevent serious complications.

Taking too much benzonatate can also be dangerous for adolescents and adults. If you or someone else has taken too much benzonatate, call Poison Control at 1-800-222-1222.

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Written by:

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP, has over a decade of experience as a pharmacist, professor, and researcher. She was a full-time clinical professor in the pharmacy practice department at D’Youville School of Pharmacy before subsequently joining the faculty of the pharmacy practice department at the University at Buffalo School of Pharmacy and Pharmaceutical Sciences.

Edited by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Reviewed by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

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