Lidocaine (9.5% w/w) is a high-potency topical formulation of the amide-type local anesthetic, lidocaine. It is primarily used as a topical anesthetic for intact skin to provide dermal analgesia for minor procedures such as venipuncture, intravenous cannulation, and superficial dermatological surgeries. In the Indian context, it is a key agent for procedural pain management in outpatient and dermatology settings. The 9.5% w/w concentration, often formulated as a medicated plaster or patch, is designed for targeted, sustained delivery.
Adult: Apply one plaster/patch (typically up to 3 plasters) to intact skin covering the most painful area. Apply for up to 12 hours in a 24-hour period. Maximum application time per day should not exceed 12 hours.
Note: 1. Apply to intact, non-irritated, non-hairy skin. 2. Clip hair if necessary; do not shave. 3. Apply plaster to dry skin. 4. Press firmly to ensure good contact. 5. Remove after recommended time (e.g., 1-5 hours for procedures, up to 12 hours for pain). 6. Wash hands after application and removal. 7. Do not apply external heat sources (heating pads) over the plaster.
Lidocaine stabilizes neuronal membranes by reversibly inhibiting the ionic fluxes required for the initiation and conduction of nerve impulses. It achieves this by binding to specific voltage-gated sodium channels on the inner portion of the neuronal cell membrane.
Pregnancy: Category B (US FDA). Animal studies show no risk, but no adequate human studies. Use only if clearly needed. Avoid large doses near term due to potential fetal bradycardia.
Driving: May cause dizziness or altered sensation. Advise patients not to drive or operate machinery until the effects, especially if applied to hands/feet, are known.
| Class I Antiarrhythmics (e.g., Mexiletine, Tocainide) | Additive cardiotoxic effects; increased risk of arrhythmias. | Major |
| CYP1A2 & CYP3A4 Inhibitors (e.g., Ciprofloxacin, Fluconazole, Amiodarone) | Increased lidocaine plasma levels, risk of toxicity. | Moderate |
| Beta-blockers (e.g., Propranolol) | Reduce hepatic blood flow, decreasing lidocaine clearance, increasing toxicity risk. | Moderate |
| Other Local Anesthetics | Additive toxic effects. | Major |
Same composition (Lidocaine (9.5% w/w)), different brands: