Cepastat Sore Throat & Cough Side Effects: What You Should Know

Cepastat Sore Throat & Cough is an over-the-counter lozenge used to temporarily relieve sore throat pain and suppress coughs. Like any medication—even OTC ones—it can cause side effects. Most are mild and go away on their own, but there are a few rare reactions you should know about.

This guide covers the common and serious side effects of Cepastat Sore Throat & Cough, who's most at risk, and when you should seek medical attention.

What Is Cepastat Sore Throat & Cough?

Cepastat Sore Throat & Cough is a sugar-free cherry lozenge containing three active ingredients:

• Benzocaine (6 mg) — a local anesthetic that numbs sore throat tissue
• Dextromethorphan HBr (5 mg) — a cough suppressant that works on the brain's cough center
• Menthol (10 mg) — provides a cooling sensation and additional pain relief

For a deeper look at how these ingredients work, see our guide on how Cepastat Sore Throat & Cough works. For full details on the product, read What Is Cepastat Sore Throat & Cough?

Common Side Effects

Most people tolerate Cepastat Sore Throat & Cough well. The most frequently reported side effects are mild and typically resolve without intervention:

Numbness of the Mouth or Throat

This is actually the intended effect of the benzocaine component—it numbs the tissue to reduce pain. However, some people find the sensation uncomfortable or more intense than expected. The numbness usually fades within 30-60 minutes after the lozenge dissolves.

Tip: Avoid eating or drinking hot liquids while your mouth is numb, as you may not feel burns.

Minor Mouth Irritation

Some users experience mild irritation in the mouth or throat after using the lozenge. This is usually temporary and may be related to the flavoring or one of the inactive ingredients.

Mild Nausea

A small number of people report mild nausea, particularly if they swallow the lozenge rather than letting it dissolve slowly. The dextromethorphan component can also contribute to mild stomach upset in some individuals.

Serious Side Effects

Serious side effects from Cepastat Sore Throat & Cough are rare, but they do exist. Know what to watch for:

Methemoglobinemia (From Benzocaine)

This is the most significant safety concern. Methemoglobinemia is a condition where the amount of oxygen carried by the blood is greatly reduced. The FDA has issued warnings about benzocaine products and this risk.

Symptoms include:

• Pale, gray, or blue-colored skin, lips, or nail beds
• Shortness of breath
• Fatigue and lightheadedness
• Rapid heart rate
• Headache
• Confusion

⚠️ If you experience any of these symptoms, stop using the product immediately and seek emergency medical care. Methemoglobinemia can occur after the first use or after repeated use.

Severe Allergic Reactions

Though uncommon, some people may have an allergic reaction to benzocaine or other ingredients. Signs of a serious allergic reaction include:

• Rash or hives
• Swelling of the face, lips, tongue, or throat
• Difficulty breathing or swallowing

If you're allergic to other "-caine" anesthetics (like procaine or lidocaine), you should avoid Cepastat Sore Throat & Cough.

Serotonin Syndrome (From Dextromethorphan Interactions)

This is primarily a concern if you're taking Cepastat alongside certain medications. Dextromethorphan can interact with MAO inhibitors, SSRIs, and SNRIs to cause serotonin syndrome—a potentially life-threatening condition.

Symptoms include:

• Agitation or restlessness
• Rapid heartbeat
• Muscle twitching or rigidity
• Dilated pupils
• High body temperature
• Diarrhea

Learn more in our drug interactions guide.

Side Effects in Specific Populations

Children

Cepastat Sore Throat & Cough should not be used in children under 6 years of age without a doctor's supervision. Children are more susceptible to methemoglobinemia from benzocaine products. The FDA specifically warns against using benzocaine in children under 2.

Pregnant or Breastfeeding Women

If you're pregnant or breastfeeding, consult a healthcare professional before using Cepastat Sore Throat & Cough. While the doses of each ingredient are relatively low, it's always best to check with your provider.

Older Adults

Older adults may be more sensitive to the dextromethorphan component, especially if they're taking other medications. Dizziness or drowsiness may be more pronounced. If you take multiple medications, review potential drug interactions with your pharmacist.

How to Manage Common Side Effects

If you experience mild side effects from Cepastat Sore Throat & Cough, here are some practical tips:

• For numbness: Wait for it to wear off before eating. Avoid hot foods and beverages.
• For mouth irritation: Drink cool water. If irritation persists, try a different lozenge brand or flavor.
• For nausea: Make sure you dissolve the lozenge slowly rather than chewing or swallowing it. Take it with a small amount of water if needed.
• For drowsiness: Avoid driving or operating machinery if you feel drowsy, especially if you've consumed alcohol.

If any side effect doesn't improve or worsens, stop using the product and consult a healthcare provider.

When to Call Your Doctor

Contact a healthcare provider if you experience:

• Side effects that don't go away or get worse
• Sore throat that lasts more than 7 days
• Sore throat accompanied by high fever, headache, rash, swelling, or nausea/vomiting
• Any signs of methemoglobinemia (blue/gray skin, shortness of breath)
• Any signs of a severe allergic reaction

Call 911 or go to the emergency room for symptoms of methemoglobinemia, severe allergic reaction, or serotonin syndrome.

Final Thoughts

Cepastat Sore Throat & Cough is generally safe for most adults and children over 6 when used as directed. The most common side effects—numbness, mild irritation, and occasional nausea—are usually minor and temporary. Serious reactions like methemoglobinemia are rare but important to recognize.

The best way to use Cepastat safely is to follow the dosage instructions (no more than 6 lozenges in 24 hours), dissolve the lozenge slowly, and be aware of potential drug interactions. If you're having trouble finding Cepastat in stores, Medfinder can help you locate it near you.