What are the alternatives to lidocaine (local anesthetic) for a patient with a lidocaine allergy?

Alternatives to Lidocaine for Patients with Lidocaine Allergy

For patients with confirmed lidocaine allergy, ester-type local anesthetics (procaine, tetracaine, benzocaine) are the first-line alternative options, with diphenhydramine injection and bacteriostatic saline as second-line choices. 1

Understanding Lidocaine Allergy

Before selecting alternatives, it's important to note:

• True immunologic reactions to lidocaine represent only 1% of all adverse reactions
• Many reported "allergies" are actually vasovagal reactions or anxiety responses 1
• Confirming true lidocaine allergy through proper testing is essential before switching to alternatives

First-Line Alternatives

Ester-Type Local Anesthetics

• Procaine - Suitable for small excisions and biopsies
• Tetracaine - Longer onset of action compared to lidocaine
• Benzocaine - Topical option for surface anesthesia
• Chloroprocaine - Particularly useful for pediatric patients and continuous epidural techniques 1

These ester-type anesthetics are preferred first-line options because:

• Cross-reactivity between amide-type (like lidocaine) and ester-type anesthetics is rare 1
• They provide effective anesthesia despite longer onset and potentially limited efficacy

Important Caution

When using ester-type anesthetics, be aware of the FDA warning that patients should not use these products if they have a history of allergy to local anesthetics such as procaine, butacaine, benzocaine, or other "caine" anesthetics 2

Second-Line Alternatives

If ester-type anesthetics are contraindicated:

1. Diphenhydramine Injection

• 1% diphenhydramine can be used for local infiltration anesthesia
• Limitations:
  • Longer onset of action
  • More painful injection compared to bacteriostatic saline 1
  • Limited duration of action

2. Bacteriostatic Saline

• Contains 0.9% benzyl alcohol in normal saline
• Less painful than diphenhydramine when injected with epinephrine
• Useful for small excisions and biopsies 1

For Procedures Requiring Longer Duration

• Consider ropivacaine if no cross-reactivity concern exists 1
• For extensive procedures where local alternatives are inadequate, general anesthesia may be necessary 3

Administration Guidelines

When using alternative anesthetics:

• Use the lowest effective dose to avoid systemic toxicity
• Aspirate before injection to avoid intravascular administration
• Monitor for signs of local anesthetic systemic toxicity (LAST) 1
• Early LAST symptoms include circumoral numbness, facial tingling, slurred speech, and metallic taste
• Progressive symptoms include seizures, CNS depression, and cardiac failure 1

Special Considerations

• For pediatric patients, use the same alternatives with appropriate dose adjustments 1
• When using any local anesthetic, be vigilant for signs of toxicity including tinnitus, light-headedness, and tingling of tongue/lips 4
• If a patient has multiple "caine" allergies, diphenhydramine or bacteriostatic saline may be the safest options

By following these guidelines and selecting appropriate alternatives based on the specific clinical scenario and confirmed allergy status, you can safely provide local anesthesia to patients with true lidocaine allergies.