Local anesthetics
Background
- Amides have two "i's" (prilocaine, lidocaine, etc)
- Esters have one "i" (tetracaine, procaine, benzocaine, etc)
- Ester local anesthetics more likely to cause allergic reaction due to metabolite PABA[1]
- If patient allergic to amides and esters, consider local Diphenhydramine (Na blocker)[2]
- Sodium channel blocker mechanism
- 1-2 mL of 1% diphenhydramine at a time, to not exceed excessive sedation dose
- Typical vial is 50 mg/mL, so to make 10 mg/mL:
- 10 mL NS removed from 50 mL vial
- Add 10 mL of 50 mg/mL diphenhydramine to 40 mL of NS
- Sedation is dose related and is similar to what would be expected for IM doses
- Relative contraindications are the same for IM diphenhydramine administration
Maximum Doses of Anesthetic Agents
Agent | Without Epinephrine | With Epinephrine | Duration | Notes |
Lidocaine | 5 mg/kg (max 300mg) | 7 mg/kg (max 500mg) | 30-90 min |
|
Mepivicaine | 7 mg/kg | 8 mg/kg | ||
Bupivicaine | 2.5 mg/kg (max 175mg) | 3 mg/kg (max 225mg) | 6-8 hr |
|
Ropivacaine | 3 mg/kg | |||
Prilocaine | 6 mg/kg | |||
Tetracaine | 1 mg/kg | 1.5 mg/kg | 3hrs (10hrs with epi) | |
Procaine | 7 mg/kg | 10 mg/kg | 30min (90min with epi) |
Side Effects
- CNS
- Perioral numbness
- Seizure
- Cardiovascular
- AV blocks
- VT and VF
- Asystole
- Allergic reaction
- Methemoglobinemia
See Also
References
- ↑ GlobalRPH. Local Anesthetics (ester and amide-type). http://www.globalrph.com/local-anesthetics.htm.
- ↑ Pavlidakey PG et al. Diphenhydramine as an Alternative Local Anesthetic Agent. J Clin Aesthet Dermatol. 2009 Oct; 2(10): 37–40.