Procaine
Novocaine
Ester local anesthetic (short-acting)
Na⁺-channel blocker; prototype ester LA. Plasma-cholinesterase metabolized to PABA.
Indications
- •Infiltration
- •Short spinal (historical)
- •Diagnostic/therapeutic injection
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Infiltration | 0.25–0.5% solution, dose-limited | — |
| Spinal (historical) | 50–200 mg 10% | — |
Maximum dose
7 mg/kg plain (absolute max 600 mg) · 10 mg/kg with epi (absolute max 1000 mg)
Max-dose calculator
single-injection infiltration / blockPlain
490 mg
With epinephrine
700 mg
| Concentration | Max volume (plain) | Max volume (with epi) |
|---|---|---|
| 1% (10 mg/mL) | 49 mL | 70 mL |
| 2% (20 mg/mL) | 24.5 mL | 35 mL |
| 10% (100 mg/mL) | 4.9 mL | 7 mL |
Ester; PABA allergy potential is the highest among LAs. Education only — confirm against the package insert. Max doses are not additive across agents; account for total LA when mixing.
Pharmacokinetics
Onset slow. Duration 45–90 min. Plasma cholinesterase → PABA.
Side effects
- !Ester (PABA) allergy — highest of the LAs
- !LAST
- !Slow onset
Contraindications
- ×Ester/PABA allergy
- ×Sulfonamide interaction (PABA)
Clinical pearls
- ★Largely historical; the reference ester LA. PABA metabolite → allergy + antagonizes sulfonamides.
- ★Slow onset + short duration limit modern use.
Other drugs in Local Anesthetics
- Lidocaine
Blocks voltage-gated Na⁺ channels in nerves (LA) and cardiac myocytes (antiarrhythmic).
- Bupivacaine
Voltage-gated Na⁺ channel blocker. Higher protein binding and lipid solubility than lidocaine → longer duration but greater cardiotoxicity.
- Ropivacaine
S-enantiomer of propivacaine. Less lipid-soluble than bupivacaine → less cardiotoxicity but slightly less potency.
- Tetracaine
Blocks voltage-gated Na⁺ channels. Long-acting ester, metabolized by plasma cholinesterase. High potency + toxicity.
- Chloroprocaine
Na⁺-channel blocker. Extremely rapid plasma-cholinesterase metabolism (half-life seconds) → lowest systemic toxicity of the LAs, ideal for OB epidural top-up.
- Prilocaine
Na⁺-channel blocker. Metabolized to o-toluidine → oxidizes hemoglobin → methemoglobinemia at high doses.
- Levobupivacaine
The S(−)-enantiomer of bupivacaine → similar block with LESS cardiotoxicity + CNS toxicity than racemic bupivacaine.
- Articaine
Amide LA that uniquely also has a thiophene ester group → partial plasma-esterase metabolism → shorter systemic half-life. Excellent bone/tissue penetration in dentistry.
Browse all classes: /reference/drugs
Suggested reading
- •Stoelting & Hines, Pharmacology & Physiology in Anesthetic Practice, 6e
- •FDA package insert
- •ASRA LAST checklist, 2020
