Should I swallow or spit out viscous lidocaine (Lidocaine) or cetacaine (Benzocaine) for throat pain?

Management of Viscous Lidocaine or Cetacaine for Throat Pain

For throat pain, patients should spit out viscous lidocaine or cetacaine (benzocaine) after application rather than swallowing it to minimize systemic absorption while maintaining local anesthetic effect.

Rationale for Spitting Rather Than Swallowing

• Topical anesthetics like lidocaine and benzocaine are designed to work locally on the mucous membranes of the throat
• Spitting out after application:
  • Reduces systemic absorption and potential toxicity
  • Still provides effective pain relief as the medication has already coated the affected area
  • Aligns with safety guidelines that emphasize minimizing total dose exposure

Dosing and Administration Guidelines

Lidocaine Application

• The maximum safe dose of topical lidocaine should not exceed 9 mg/kg of lean body weight 1
• For throat pain:
  1. Apply the prescribed amount to the affected area
  2. Allow 1-2 minutes for the medication to coat the mucosa and take effect
  3. Spit out any remaining medication
  4. Do not eat or drink for 30-60 minutes after application

Benzocaine (Cetacaine) Application

• Similar principles apply to cetacaine application
• Research shows that higher concentrations of lidocaine (8 mg) don't necessarily provide better pain relief than lower concentrations (1 mg) for sore throat 2
• The antiseptic component (cetylpyridinium chloride) works in conjunction with the anesthetic

Safety Considerations

Potential Risks of Swallowing

• Increased systemic absorption may lead to:
  • Higher risk of local anesthetic toxicity
  • Potential numbing of the esophagus and increased risk of aspiration
  • Unnecessary exposure to medication beyond the target area

Signs of Local Anesthetic Toxicity to Monitor

• Early warning signs include 3:
  • Circumoral numbness
  • Facial tingling
  • Light-headedness
  • Tinnitus
  • Metallic taste

Special Populations and Precautions

• Children require lower doses of topical anesthetics 3
• Contraindications include 3:
  • True lidocaine/benzocaine allergy
  • Active infections
  • Severe cardiac disease
  • Electrolyte disorders
  • Seizure disorders

Alternative Options

• Lozenges containing lidocaine (1-8 mg) may be effective for sore throat pain 2, 4
• Non-pharmacological approaches:
  • Warm salt water gargles
  • Throat sprays
  • Cold beverages or ice chips

Conclusion

When using viscous lidocaine or cetacaine for throat pain, the medication should be applied topically and then spit out rather than swallowed. This approach maximizes local anesthetic effect while minimizing systemic absorption and potential toxicity. The effectiveness of the medication is not compromised by spitting it out, as the active ingredients work through contact with the affected mucosa.