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 true lidocaine allergy, ester-type local anesthetics (such as procaine or tetracaine) should be used as the first-line alternative, with diphenhydramine injection or bacteriostatic normal saline as second-line options. 1

Understanding Lidocaine Allergy

True allergic reactions to lidocaine are rare, accounting for only about 1% of all adverse reactions reported. Many reported "allergies" are actually vasovagal reactions or anxiety responses rather than true immunologic reactions 1. Before selecting an alternative:

• Confirm whether the reaction was a true allergy versus a vasovagal response
• Determine if the patient is allergic to the amide anesthetic itself or to preservatives
• Note that patients allergic to methylparaben or para-aminobenzoic acid derivatives may not have cross-sensitivity to amide anesthetics 2

First-Line Alternatives

Ester-Type Local Anesthetics

• Examples: Procaine, tetracaine, benzocaine
• Advantages: Rare cross-reactivity with amide anesthetics like lidocaine 1
• Limitations: Longer onset of action (5 minutes vs. 1 minute for lidocaine) and potentially limited efficacy 1
• Best for: Small excisions and biopsies

Second-Line Alternatives

1. Bacteriostatic Normal Saline

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

2. Diphenhydramine (1%)

• Can be used as an alternative form of local infiltration anesthesia 3
• Limitations: Longer onset of action and more painful injection compared to bacteriostatic saline 1

Alternative Amide Anesthetics

If the patient's allergy is specific to lidocaine but not to all amide anesthetics, consider:

Mepivacaine

• An amide-type anesthetic like lidocaine
• Important: Should only be used if cross-reactivity is ruled out, as patients allergic to one amide may react to others 2, 4
• Patients allergic to methylparaben have not shown cross-sensitivity to amide-type agents like mepivacaine 2

Ropivacaine

• Consider for procedures requiring longer duration 1
• Only if no cross-reactivity concern exists

Special Considerations

Cross-Reactivity

• Cross-reactivity between amide-type and ester-type anesthetics is rare 1
• However, cross-reactivity among different amide anesthetics (lidocaine, mepivacaine, ropivacaine) can occur 4
• In one case study, a patient allergic to mepivacaine also reacted to lidocaine and ropivacaine but tolerated bupivacaine and levobupivacaine 4

Pediatric Considerations

• For children, the same alternatives can be used with appropriate dose adjustments 3, 5
• Chloroprocaine (an ester) has been used primarily for continuous epidural techniques in infants and children due to its short duration 5

Safety Precautions

When using any alternative anesthetic:

• Use the lowest effective dose to avoid systemic toxicity 2
• Aspirate before injection to avoid intravascular administration 2
• Monitor for signs of local anesthetic systemic toxicity (LAST), including circumoral numbness, facial tingling, slurred speech, and metallic taste 1
• Have emergency equipment available

Algorithm for Selection

1. Confirm true lidocaine allergy (not just anxiety reaction)
2. First choice: Ester-type local anesthetic (procaine, tetracaine)
3. Second choices (if ester anesthetics unavailable or contraindicated):
   • Bacteriostatic normal saline (preferred for less pain)
   • 1% diphenhydramine injection
4. Consider alternative amide anesthetics only after allergy testing to rule out cross-reactivity

Remember that mortality from local anesthetics is extremely rare (1:1,500,000 to 1:4,000) 6, but proper selection of alternatives in truly allergic patients is essential for patient safety.