Lidocaina Pls (Lidocaine)

Lidocaine is a topical local anesthetic used to numb skin and mucous membranes, reducing pain from minor injuries and irritations.

• Minor burns: provides rapid pain relief and surface anesthesia.
• Insect bites: reduces itching and discomfort through local numbing.
• Hemorrhoids: alleviates pain and irritation of the anal area.
• Superficial skin lesions: numbs the area to facilitate minor procedures or relieve discomfort.

• Topical lidocaine penetrates the epidermis and binds to voltage‑gated sodium channels on neuronal membranes. By stabilizing the inactive state of these channels, it blocks sodium influx required for depolarization, inhibiting initiation and propagation of nerve impulses. This localized interruption of signal transmission results in loss of sensation in the treated area without affecting systemic nerve function.

Topical lidocaine may cause a range of local and systemic adverse reactions, most of which are mild and reversible.

Common Side Effects

• Skin irritation: redness or mild rash at the application site.
• Burning sensation: transient warmth or stinging when first applied.
• Pruritus: itching of the treated area.
• Edema: mild swelling around the site.
• Allergic dermatitis: localized allergic skin reaction.
• Dryness: temporary dryness of the skin.

Serious or Rare Side Effects

• Systemic toxicity: dizziness, seizures, or altered mental status from excessive absorption.
• Cardiac arrhythmias: irregular heart rhythm in cases of high systemic levels.
• Anaphylaxis: severe, life‑threatening allergic reaction.
• Methemoglobinemia: reduced oxygen‑carrying capacity of blood.
• Tissue necrosis: localized tissue death with prolonged use.
• Severe skin ulceration: deep ulcer formation at the site.

When using Lidocaina Pls, several precautions should be observed to ensure safety and effectiveness.

• Application area: limit to intact skin or mucous membranes, avoid broken skin.
• Dosage amount: use only the amount recommended by the prescriber to prevent systemic absorption.
• Duration of use: do not exceed the prescribed treatment period, typically not more than several days.
• Concurrent anesthetics: avoid using other topical anesthetics on the same area to reduce cumulative toxicity.
• Patient sensitivity: discontinue if signs of allergic reaction appear.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Lidocaine can interact with other medicines, altering its safety profile or effectiveness.

Major Interactions (Avoid)

• Other local anesthetics: concurrent use may increase risk of systemic toxicity.
• Class I antiarrhythmic drugs (e.g., quinidine, procainamide): additive cardiac effects.
• CYP3A4 inhibitors (e.g., ketoconazole, erythromycin): may raise lidocaine plasma levels.
• High‑dose epinephrine: can enhance systemic absorption leading to toxicity.
• Alcohol or CNS depressants: may potentiate central nervous system effects.

Moderate Interactions (Monitor Closely)

• Beta‑blockers: may affect heart rate when systemic absorption occurs.
• Diuretics: can alter lidocaine clearance, requiring monitoring.
• Anticonvulsants: may increase seizure threshold when combined.
• Herbal supplements (e.g., St. John’s wort): possible enzyme induction affecting metabolism.
• Other topical agents: may change absorption rate, requiring observation.