Lidocaine + Epinephrine

Approved Indications:

• Local and Regional Anesthesia:
• Infiltration anesthesia for minor surgical and dental procedures.
• Peripheral nerve block (e.g., brachial plexus block, intercostal block).
• Field block, spinal, and epidural anesthesia.
• Hemostasis During Surgery:
• Epinephrine causes local vasoconstriction to reduce bleeding during procedures.

Clinically Accepted Off-label Uses:

• Prolonged Postoperative Analgesia
• Minor Cosmetic and Dermatologic Procedures: Skin lesion excision, suturing, laser treatments.

Adults:

• Infiltration Anesthesia: Lidocaine 0.5% to 1% with epinephrine (1:100,000 or 1:200,000).
• Maximum dose: 7 mg/kg of lidocaine with epinephrine (not exceeding 500 mg total).
• Peripheral Nerve Block: Lidocaine 1% with epinephrine (1:200,000).
• Epidural Anesthesia: Lidocaine 1.5% with epinephrine (1:200,000).

Pediatrics:

• Maximum dose: 3–5 mg/kg of lidocaine with epinephrine.
• Use lower concentration solutions and monitor closely.

Elderly:

• Use lower doses; increased sensitivity due to reduced hepatic metabolism and comorbidities.

Renal/Hepatic Impairment:

• Use with caution. Dose reduction may be necessary to avoid systemic toxicity.

Route of Administration:

• Infiltration, subcutaneous, nerve block, epidural, or spinal injection.
• Important: Always aspirate before injection to avoid intravascular administration.

Lidocaine is an amide-type local anesthetic that inhibits voltage-gated sodium channels on the neuronal cell membrane, preventing the generation and propagation of action potentials, resulting in localized anesthesia. Epinephrine, a sympathomimetic agent, acts on alpha-adrenergic receptors to cause vasoconstriction, reducing systemic absorption of lidocaine, thereby prolonging its action, minimizing toxicity, and reducing bleeding at the site of injection.

• Absorption: Rapid absorption from injection site; reduced by epinephrine-induced vasoconstriction.
• Onset of Action: 1 to 5 minutes depending on the administration site.
• Duration of Action: 60–180 minutes (prolonged with epinephrine).
• Distribution: Widely distributed; crosses the blood-brain barrier and placenta.
• Metabolism: Hepatically metabolized (mainly via CYP1A2 and CYP3A4).
• Excretion: Renal elimination of metabolites.
• Half-life: Approximately 90–120 minutes (may be prolonged in hepatic impairment).

• Pregnancy Category:
• Lidocaine: Category B – Animal studies show no fetal harm. Use only if clearly needed.
• Epinephrine: Category C – May reduce uterine blood flow. Use only in life-threatening situations.
• Lactation:
• Lidocaine is excreted in small amounts in breast milk. Generally considered safe.
• Epinephrine is also excreted in breast milk in trace amounts; caution is advised.

• Primary Class: Local Anesthetic
• Subclass: Amide-type local anesthetic combined with vasoconstrictor (sympathomimetic)

• Known hypersensitivity to lidocaine, epinephrine, or other amide-type anesthetics
• Severe heart block or arrhythmia without pacemaker support
• Use in areas supplied by end-arteries (e.g., fingers, toes, ears, nose, penis) unless diluted and used with extreme caution
• Local infection at the injection site
• Concomitant use of monoamine oxidase inhibitors (within 14 days)

• Avoid intravascular injection – always aspirate before injection.
• CNS toxicity risk: early symptoms include tinnitus, confusion, and seizures.
• Cardiac toxicity: arrhythmias, bradycardia, and hypotension possible with high doses.
• Use with caution in elderly, hepatic dysfunction, seizure disorders, and cardiac disease.
• Use caution in hyperthyroid or hypertensive patients due to epinephrine effects.
• Avoid repeated injections in short intervals.

Common:

• Local irritation or swelling at injection site
• Dizziness, tingling, or drowsiness
• Mild increase in heart rate or blood pressure

Serious or Rare:

• Seizures (due to systemic lidocaine toxicity)
• Hypotension or bradycardia
• Ventricular arrhythmias (from epinephrine)
• Allergic reactions including rash or anaphylaxis
• Tissue necrosis if used in end-arterial areas
• Methemoglobinemia (rare)

• MAO Inhibitors / Tricyclic Antidepressants: Risk of hypertensive crisis with epinephrine.
• Beta-Blockers: Can enhance epinephrine’s vasoconstrictive effects.
• Antiarrhythmic Drugs: Additive toxicity with other sodium channel blockers.
• Inhalational Anesthetics (e.g., halothane): May increase risk of cardiac arrhythmias with epinephrine.
• CYP3A4 Inhibitors (e.g., ketoconazole): May reduce lidocaine metabolism, increasing toxicity.

• New safety guidelines emphasize aspiration before injection to prevent intravascular administration.
• Emerging literature supports the cautious use of epinephrine-containing solutions in digits and end-arterial areas, if appropriately diluted.
• Emphasis on limiting cumulative lidocaine doses in prolonged or repeated procedures.

• Storage Temperature: 20°C to 25°C (68°F to 77°F)
• Light Protection: Protect from direct light; store in original packaging.
• Humidity: Store in a dry environment.
• Do Not Freeze.
• Single-use vials: Discard any unused portion after opening.
• Solution Stability: Do not use if discolored or containing particulate matter.