Strongest Concentration of Procaine for Local Anesthesia
The strongest concentration of procaine hydrochloride used as a local anesthetic is 20% (200 mg/mL), though this concentration is rarely used in clinical practice due to safety concerns. 1
Available Concentrations and Clinical Usage
- Procaine is commercially available in 1% (10 mg/mL) and 2% (20 mg/mL) concentrations for routine clinical use as described in the FDA labeling 1
- Higher concentrations (up to 20%) have been used in specialized settings but are not commonly available in commercial preparations 2
- Procaine is classified as a relatively weak, short-acting ester-type local anesthetic with duration of action between 60-90 minutes 3
Maximum Safe Dosing
- The maximum recommended dose of procaine with epinephrine is 10 mg/kg 2
- The maximum recommended dose of procaine without epinephrine is 6-7 mg/kg 2
- For dental applications, the maximum dose with epinephrine is 6 mg/kg 2
Safety Considerations
- All local anesthetic agents are cardiac depressants and may cause central nervous system excitation or depression 2
- Weight-based dosing calculations should always be performed before administration to prevent toxicity 2
- Procaine has been shown to have less neurotoxicity compared to other local anesthetics such as mepivacaine, prilocaine, and bupivacaine in animal studies 4
- Signs of local anesthetic toxicity include perioral numbness, facial tingling, slurred speech, metallic taste, auditory changes, and hallucinations, potentially progressing to seizures or central nervous system depression 2
Clinical Applications
- Procaine is used for local infiltration and peripheral nerve blocks 1
- It has a faster recovery time to normal function compared to other local anesthetics in some studies 4
- In cardiac surgery, procaine has been shown to stabilize post-ischemic rhythm when added to cardioplegia solutions 5
Practical Considerations
- The pH of procaine solutions is adjusted between 3 and 5.5 1
- Commercial preparations contain acetone sodium bisulfite as an antioxidant and may contain chlorobutanol as an antimicrobial preservative 1
- When using procaine for local anesthesia, frequent aspiration is recommended to minimize the likelihood of intravascular injection 2
While 20% concentration exists, most clinical applications use the much lower 1-2% concentrations due to the improved safety profile and adequate efficacy at these lower concentrations.