NOVOCAIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NOVOCAIN (NOVOCAIN).
Procaine, an ester-type local anesthetic, reversibly binds to the intracellular portion of voltage-gated sodium channels, inhibiting sodium influx and blocking nerve impulse conduction.
| Metabolism | Primarily hydrolyzed by plasma pseudocholinesterase (butyrylcholinesterase) to para-aminobenzoic acid (PABA) and diethylaminoethanol; hepatic metabolism minor. |
| Excretion | Renal excretion of para-aminobenzoic acid (PABA) and diethylaminoethanol as major metabolites; <2% excreted unchanged in urine. Biliary/fecal: minimal. |
| Half-life | Plasma half-life: approximately 30–60 seconds due to rapid hydrolysis by pseudocholinesterases; clinical effects short-lived. |
| Protein binding | Approximately 85% bound to plasma proteins (primarily alpha-1-acid glycoprotein and albumin). |
| Volume of Distribution | Vd: approximately 0.7–1.0 L/kg; reflects distribution into total body water with rapid tissue uptake. |
| Bioavailability | Oral: negligible due to extensive first-pass hydrolysis; Parenteral (IV/SC/IM): 100% for local anesthesia. |
| Onset of Action | Infiltration: 2–5 min; Nerve block: 5–15 min; Topical: not effective due to poor mucosal penetration. |
| Duration of Action | Infiltration: 30–60 min; Nerve block: 45–90 min; duration prolonged with epinephrine (up to 2 hours). |
| Molecular Weight | 236.31 |
Local infiltration: 0.5% solution, up to 20 mL (100 mg) per dose; nerve block: 1-2% solution, 5-10 mL (50-200 mg); maximum single dose: 7 mg/kg or 350 mg (without epinephrine).
| Dosage form | INJECTABLE |
| Renal impairment | No specific guidelines; use with caution in severe renal impairment (GFR <30 mL/min) due to risk of metabolic acidosis from procaine metabolism. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated. |
| Pediatric use | Local infiltration: 0.5% solution, 2.5-5 mg/kg (max 100 mg); nerve block: 1% solution, 2.5-5 mg/kg; maximum single dose: 5 mg/kg. |
| Geriatric use | Reduce maximum single dose to 5 mg/kg (max 250 mg); monitor for hypotension and CNS excitation; dose intervals at least 2 hours. |
| 1st trimester | Procaine crosses the placenta. Animal studies have not shown fetal harm but adequate human studies are lacking. Use only if clearly needed. |
| 2nd trimester | Procaine crosses the placenta. No known teratogenicity in humans; use with caution. |
| 3rd trimester | Procaine is generally considered safe near term when used for local anesthesia. Avoid large doses as they may cause neonatal CNS depression. |
Clinical note
Comprehensive clinical and safety monograph for NOVOCAIN (NOVOCAIN).
| Placental transfer | Procaine rapidly crosses the placenta by passive diffusion. Fetal plasma levels reach approximately 50-60% of maternal levels within minutes of administration. |
| Breastfeeding | Procaine is excreted into breast milk in minimal amounts. However, due to short half-life and poor oral bioavailability, adverse effects in nursing infants are unlikely. The American Academy of Pediatrics considers it compatible with breastfeeding. |
■ FDA Black Box Warning
Not available.
| Serious Effects |
Hypersensitivity to procaine or other ester-type local anestheticsHypersensitivity to para-aminobenzoic acid (PABA) or its derivativesMyasthenia gravis (risk of exacerbation due to neuromuscular blocking effects)Known pseudocholinesterase deficiency (risk of prolonged toxicity)Severe bradycardia or heart block (for intravenous use)
| Precautions | Risk of methemoglobinemia, especially with high doses or in patients with G6PD deficiency, Cardiovascular effects: hypotension, arrhythmias, cardiac arrest, CNS toxicity: restlessness, seizures, respiratory depression, Allergic reactions to ester anesthetics (cross-sensitivity with PABA) |
| Food/Dietary | No specific food interactions have been reported with procaine hydrochloride. Patients should avoid consuming alcohol before or after administration, as it may exacerbate central nervous system side effects (e.g., dizziness, sedation). No other dietary restrictions are required. |
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| Lactation Rating | L2 (Safer) |
| Teratogenic Risk | Procaine (Novocain) is a pregnancy category C drug. Animal reproduction studies have not been conducted. Inadvertent intravascular administration may cause fetal bradycardia and acidosis. Use in first trimester only if clearly needed; potential for placental transfer. Avoid in third trimester near term due to risk of neonatal CNS depression. |
| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and ECG during administration. Fetal heart rate monitoring recommended if used during pregnancy. Assess for signs of local anesthetic systemic toxicity (LAST) including CNS and cardiovascular effects. |
| Fertility Effects | No specific studies available. No evidence of significant impact on fertility. As an ester local anesthetic, no known hormonal effects. |
| Clinical Pearls | Procaine hydrochloride (Novocain) is an ester-type local anesthetic with rapid onset but short duration (<1 hour). Contains a para-aminobenzoic acid (PABA) moiety, which can cross-react with sulfonamide antibiotics. Contraindicated in patients with pseudocholinesterase deficiency (risk of prolonged effect). Metabolized by plasma cholinesterase; avoid in patients with myasthenia gravis or those receiving anticholinesterase therapy (e.g., neostigmine). Use with caution in patients with cardiac conduction disorders (e.g., AV block) due to its quinidine-like antiarrhythmic effects and potential for myocardial depression. |
| Patient Advice | Novocain is a local anesthetic used for minor surgical procedures, especially dental work; it numbs only the area where it is injected. · You may experience temporary numbness, tingling, or loss of sensation in the treated area; avoid eating, drinking, or chewing gum until sensation returns to prevent injury. · Report any signs of allergic reaction (rash, hives, difficulty breathing) to your healthcare provider immediately; this medication contains PABA, so avoid if you have a sulfonamide allergy. · Do not use any over-the-counter pain relievers unless approved by your doctor, as they may interact with Novocain. · If you have a history of liver disease, kidney disease, heart rhythm problems, or myasthenia gravis, inform your healthcare provider before receiving Novocain. · This medication is not intended for self-administration; it is administered only by a healthcare professional. |