Viscous Lidocaine Swish-and-Spit Dosing Frequency
For adults using 2% viscous lidocaine solution for oral pain relief, swish-and-spit can be performed every 3 hours, with a maximum of 8 doses in 24 hours, using 15 mL (one tablespoon) per dose. 1
Adult Dosing Protocol
- Frequency: Administer no more often than every 3 hours 1
- Maximum daily doses: 8 doses per 24-hour period 1
- Volume per dose: 15 mL (one tablespoon) of 2% solution 1
- Maximum single dose: Must not exceed 300 mg total lidocaine (equivalent to 15 mL of 2% solution) 1
- Technique: Swish the undiluted solution around in the mouth, then spit out—do not swallow 1
Safety Profile with Swish-and-Spit Technique
The swish-and-spit method is remarkably safe because systemic absorption is minimal:
- When 15 mL of 2% lidocaine (300 mg) was swished and spit out every 3 hours for 8 consecutive doses, plasma lidocaine levels never exceeded 0.3 mcg/mL—well below toxic thresholds 2
- Even when the same dose was swallowed (worst-case scenario), peak plasma levels only reached 0.8 mcg/mL after the eighth dose, still far below toxic ranges 2
- All lidocaine and metabolites were essentially undetectable by 12 hours after the last dose 2
Critical Safety Considerations
Common pitfall: The 3-hour minimum interval is non-negotiable. More frequent dosing increases the risk of cumulative toxicity, particularly in patients with hepatic impairment where lidocaine metabolism is reduced 1
Weight-based maximum: The dose must not exceed 4.5 mg/kg or 2 mg/lb body weight per administration, with an absolute ceiling of 300 mg regardless of patient size 1
Early toxicity signs to monitor: Peri-oral tingling, tinnitus, light-headedness, and restlessness appear before cardiovascular symptoms 3
Pediatric Dosing (If Applicable)
For children over 3 years of age, dosing is weight-based and significantly lower than adults: