What is the recommended dose of lidocaine (local anesthetic) for vaginal repair?

Lidocaine Dosing for Vaginal Repair

For vaginal repair procedures, the maximum recommended dose of lidocaine with epinephrine is 7 mg/kg, not to exceed a total of 500 mg when administered incrementally over time. 1

Dosing Guidelines

Maximum Safe Doses

• Adults:
  • With epinephrine: 7 mg/kg (not exceeding 500 mg total)
  • Without epinephrine: 4.5 mg/kg 1
• Children:
  • With epinephrine: 3.0-4.5 mg/kg
  • Without epinephrine: 1.5-2.0 mg/kg 1
• Absolute maximum: No more than 120 mg/h should be infused for any patient 1

Weight Considerations

• Use ideal body weight for dose calculations 1
• For women: ideal body weight = (height in cm - 105)
• Lidocaine should not be used in patients weighing <40 kg 1

Administration Technique for Vaginal Repair

1. Preparation:

   • Calculate maximum allowable dose before administration 1
   • Standard concentration: 1% lidocaine (10 mg/mL) or 2% lidocaine (20 mg/mL) 1
   • Addition of epinephrine (typically 1:100,000 or 1:200,000) prolongs effect and reduces bleeding 1

2. Technique for minimizing pain during injection:

   • Buffer lidocaine with bicarbonate
   • Warm the lidocaine before injection
   • Inject slowly with a small-gauge needle 1
   • Consider pre-application of topical anesthetic (EMLA cream) to reduce discomfort of infiltration 2, 3

3. Timing:

   • Allow 5-10 minutes after injection before beginning the procedure to ensure adequate anesthesia 3

Special Considerations

Risk Factors for Toxicity

• Procedure complexity: Vaginal hysterectomy with additional reconstruction requires higher doses (average 228 mg) compared to vaginal reconstruction alone (average 168 mg) 4
• Multiple procedures: Concomitant procedures increase risk of approaching toxic doses 4
• Timing: Do not administer other local anesthetics within 4 hours of vaginal repair 1

Signs of Lidocaine Toxicity

Early signs include:

• Circumoral numbness
• Facial tingling
• Slurred speech
• Metallic taste
• Auditory changes
• Hypertension and tachycardia 1

Advanced signs include:

• Seizures
• CNS depression
• Cardiac failure or arrest 1

Alternative Options

• For patients with true lidocaine allergy:
  • Ester-type local anesthetics (procaine, chloroprocaine)
  • 1% diphenhydramine
  • Bacteriostatic normal saline (0.9% benzyl alcohol in normal saline) 1
• Topical options:
  • EMLA cream (lidocaine 2.5% and prilocaine 2.5%) for superficial procedures 2, 3
  • Lidocaine gel (2.5%, 5%, or 10%) for minimally invasive procedures 5

Safety Measures

• Use the lowest effective dose
• Aspirate before injection to avoid intravascular administration
• Administer in incremental injections
• Continuously monitor patient for signs of toxicity 1
• Have lipid emulsion available for treatment of local anesthetic systemic toxicity 1

For vaginal repairs, careful calculation of the lidocaine dose based on the patient's weight and anticipated procedure complexity is essential to maintain safety while providing adequate anesthesia.