Can Benzonatate Cause Diarrhea?

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Can Benzonatate Cause Diarrhea?

By Your Health Magazine Health Information Team

Benzonatate is not generally known to cause diarrhea. Diarrhea is not listed among the recognized gastrointestinal side effects in current official prescribing information. However, people can have unexpected reactions to medicines, and diarrhea that begins after taking benzonatate should be monitored. An infection, another medication, a food-related illness, or the condition causing the cough may be a more likely explanation.

What the Official Side-Effect Information Says

Benzonatate is the active ingredient in a prescription, non-narcotic cough suppressant. It is supplied as a capsule or liquid-filled capsule and works by reducing the cough reflex in the lungs and airways. It may be sold as a generic medication or under brand names such as Tessalon.

The DailyMed prescribing information for benzonatate, revised in December 2025, lists the following potential gastrointestinal effects:

• Nausea
• Constipation
• General gastrointestinal upset

Diarrhea is not specifically listed. The MedlinePlus benzonatate drug information also lists nausea and constipation, rather than diarrhea, among the medication’s expected digestive side effects.

This does not prove that benzonatate could never contribute to loose stools in an individual. Medication labels cannot describe every symptom reported by every patient. Still, if diarrhea is the only new symptom, it is reasonable to consider other causes rather than assuming benzonatate is responsible.

Why Diarrhea May Develop While Taking Benzonatate

Several problems can occur at the same time as a cough and may explain diarrhea more convincingly than benzonatate itself:

• A viral infection: Some viruses cause both respiratory and digestive symptoms.
• Food poisoning or a separate stomach infection: The timing may happen to overlap with starting the medicine.
• Other medications: Antibiotics, magnesium-containing antacids, certain supplements, and some liquid medicines can cause diarrhea.
• Diet changes: Sugar-free cough drops and syrups may contain sugar alcohols that loosen stools in some people.
• An existing digestive condition: Food intolerances, irritable bowel syndrome, inflammatory bowel disease, and other gastrointestinal disorders may contribute.

If digestive symptoms are occurring along with heartburn or regurgitation, it may also help to understand the possible relationship between acid reflux and diarrhea. Reflux itself is not usually a direct cause, but associated illnesses, dietary triggers, or treatments may affect bowel habits.

Can Benzonatate Cause Dizziness?

Yes, benzonatate can cause dizziness. Dizziness, headache, drowsiness, sedation, confusion, and visual hallucinations are among the potential nervous-system effects included in official drug information.

If you are wondering whether benzonatate causes dizziness because you have both dizziness and diarrhea, either symptom could have a different explanation. Benzonatate may directly cause dizziness, while frequent diarrhea can also make a person lightheaded by causing dehydration.

If dizziness occurs, sit or lie down until it passes and avoid driving or operating machinery while impaired. Contact a healthcare professional if dizziness is persistent, severe, or accompanied by fainting, confusion, weakness, chest pain, or difficulty breathing.

What to Do If Diarrhea Starts After Benzonatate

1. Check the timing. Note when the diarrhea began, when benzonatate was started, and whether symptoms appear after each dose.
2. Review everything you are taking. Include antibiotics, over-the-counter cold remedies, antacids, vitamins, supplements, and sugar-free products.
3. Watch for dehydration. Warning signs include dry mouth, intense thirst, dark urine, urinating less often, unusual tiredness, dizziness, or lightheadedness.
4. Replace fluids. For mild diarrhea, drinking fluids can help replace losses. People with kidney, heart, or other conditions that affect fluid intake should follow guidance from their healthcare professional.
5. Consult a pharmacist or prescriber. They can assess whether the timing suggests a medication reaction and advise you without making an unsafe change to your prescription.

Do not stop or change a prescription medicine solely because of an online article. A clinician or pharmacist can consider your complete medication list, health history, and symptoms. General medication information is also available through the MedlinePlus drug information resource.

Use Benzonatate Safely

Benzonatate capsules must be swallowed whole. Breaking, chewing, crushing, dissolving, or sucking a capsule can release the medication in the mouth, causing rapid numbness of the tongue or throat, choking, and potentially severe reactions.

Keep benzonatate securely out of children’s sight and reach. Safety and effectiveness have not been established for children younger than 10, and accidental ingestion can cause seizures, cardiac arrest, coma, or death very quickly. If a child swallows benzonatate, seek emergency help immediately rather than waiting for symptoms.

When to Seek Care

Contact a healthcare professional promptly if diarrhea lasts longer than two days, occurs six or more times in one day, or is accompanied by a high fever, frequent vomiting, severe abdominal or rectal pain, black stools, blood or pus in the stool, or signs of dehydration. The National Institute of Diabetes and Digestive and Kidney Diseases provides additional guidance on diarrhea symptoms and when medical evaluation is appropriate.

Get emergency help for difficulty breathing or swallowing, throat tightening, collapse, a seizure, severe confusion, hallucinations, or inability to awaken the person. For a suspected overdose or accidental ingestion, call 911 when severe symptoms are present and contact Poison Control at 1-800-222-1222 immediately.

In summary, diarrhea is not an expected or commonly listed side effect of benzonatate, while dizziness is a recognized potential effect. New, persistent, or severe symptoms should be discussed with a pharmacist or prescribing healthcare professional so that medication effects and other possible causes can be evaluated safely.