| Drug Class |
Amide‑type local anesthetic (also a class 1b anti‑arrhythmic in IV form). |
| Typical Form |
Topical ointment, gel, spray or cream; 1 % concentration means 10 mg of lidocaine per gram of product. |
| Primary Uses |
• Cutaneous (skin) numbing for minor procedures (e.g., bandage changes, superficial wound cleaning).
• Topical treatment of minor burns, sunburn, and post‑excisional wounds.
• Relief of itching or pain from hemorrhoids, insect bites, or mild neuropathic skin pain. |
| Common Brands |
LMX (Lidocaine 1 % Cream), Loco‑Pain, Lidoderm, etc. |
| Administration Tips |
1. Clean the area before applying.
2. Apply a thin layer; don’t exceed the recommended amount (usually a pea‑size to a 1 cm² area, depending on the product).
3. Cover with a sterile gauze if the area will be exposed to water or friction.
4. Do not apply to large, broken, or infected skin areas unless instructed by a clinician.
5. For intra‑oral use, follow dentist instructions and avoid swallowing. |
| Typical Dose (Topical) |
• 1 % cream: 1–2 g on the affected area 3–4 × day.
• Gel or spray: 2–4 mL (or a light “spray”) 2–3 × day.
• Do not use more than 4 g (or 8–10 mL) per 24 h without a doctor’s order.
• For infants, limit to 0.5–1 g per 24 h; pediatric dosing should be guided by a professional. |
| Pharmacokinetics |
• Onset: 5–15 min (may be longer if the skin is dry or thick).
• Peak effect: 30–60 min.
• Duration: 1–6 h, depending on skin type and amount applied.
• Systemic absorption is minimal when used on intact skin; higher with broken skin or mucous membranes. |
| Common Side Effects |
• Mild skin irritation or redness.
• Burning, tingling, or pruritus at the application site.
• Rarely, temporary numbness that can persist if over‑applied.
• Systemic side effects (rare): dizziness, headache, or metallic taste. |
| Serious (but rare) Side Effects |
• Allergic reaction: rash, itching, swelling, dizziness, or difficulty breathing.
• Local anesthetic systemic toxicity (LAST): confusion, seizures, arrhythmias, or cardiac arrest if large amounts are absorbed.
• Serotonin syndrome if used with serotonergic drugs (e.g., SSRIs). |
| Contraindications |
• Known hypersensitivity to lidocaine or other amide local anesthetics.
• Severe hepatic impairment (as lidocaine is metabolized by the liver).
• Severe heart block or other arrhythmia unless monitored. |
| Drug Interactions |
• Monoamine oxidase inhibitors (MAOIs): risk of severe hypertension or seizures.
• CYP3A4 inhibitors or inducers (e.g., ketoconazole, rifampin) can alter systemic lidocaine levels.
• Other local anesthetics (especially benzocaine): additive risk of systemic toxicity.
• Beta‑blockers: may worsen cardiovascular side effects if toxicity occurs. |
| Special Populations |
• Pregnancy: Category C; use only if benefits outweigh potential risks.
• Breastfeeding: minimal transfer; safe but monitor infant if large amounts applied.
• Children: use pediatric‑approved formulations; limit dose to <1 g/24 h. |
| Storage |
Store at 20–25 °C (room temperature); keep out of reach of children. Avoid freezing. |
| How to Store and Dispose |
• Keep container sealed when not in use.
• Dispose unused topicals by flushing down the toilet (unless local regulations advise otherwise).
• For large or unused volumes, check local pharmacy guidelines. |
| When to Seek Medical Attention |
• Signs of an allergic reaction (difficulty breathing, swelling of lips/face).
• Rapid heartbeat, chest pain, or confusion.
• Persistent numbness lasting >24 h. |