Lidoposterin (Lidocaine)

Lidoposterin is a rectal local anesthetic used to relieve pain in conditions affecting the anorectal region.

• Proctalgia fugax: provides rapid relief of transient anal canal muscle spasm pain.
• Anal fissure: reduces pain during bowel movements and facilitates healing.
• Hemorrhoidal disease: alleviates discomfort and itching associated with internal hemorrhoids.

• Lidocaine blocks voltage‑gated sodium channels on neuronal membranes, stabilizing the neuronal membrane and preventing the initiation and propagation of action potentials. By inhibiting sodium influx, it reduces the transmission of nociceptive signals from the rectal mucosa, producing a localized anesthetic effect without significant systemic activity at therapeutic concentrations. The effect is concentration‑dependent and reversible, allowing normal sensation to return as the drug is metabolized locally.

Lidoposterin may cause adverse reactions at the site of application or, rarely, systemic effects.

Common Side Effects

• Local irritation: mild burning or stinging at the rectal mucosa.
• Numbness: temporary loss of sensation in the treated area.
• Pruritus: itching around the application site.
• Mild gastrointestinal discomfort: transient cramping or soft stools.

Serious or Rare Side Effects

• Systemic toxicity: dizziness, seizures, or cardiac arrhythmias if absorbed in large amounts.
• Allergic reaction: rash, swelling, or difficulty breathing.
• Methemoglobinemia: bluish discoloration of skin and lips, indicating reduced oxygen delivery.
• Severe hypotension: sudden drop in blood pressure.

When using Lidoposterin, consider the following precautions to ensure safe and effective therapy.

• Patient assessment: evaluate for rectal mucosal lesions or infections before administration.
• Dose limitation: avoid exceeding recommended frequency to reduce risk of systemic absorption.
• Drug interactions: review concomitant use of other local anesthetics or sodium channel blockers.
• Pregnancy and lactation: use only if clearly needed, as safety data are limited.
• Monitoring: observe for signs of systemic toxicity, especially in patients with hepatic impairment.
• Store at ambient temperature: keep below 25 °C, protect from moisture and direct sunlight.

Lidoposterin can interact with other medicines that affect sodium channels or systemic absorption.

Major Interactions (Avoid)

• Other local anesthetics: concurrent use may increase risk of systemic toxicity.
• Class I antiarrhythmics (e.g., quinidine, procainamide): additive cardiac conduction effects.

Moderate Interactions (Monitor Closely)

• CYP450 inhibitors: may slow lidocaine metabolism, raising plasma levels.
• Beta‑blockers: can potentiate cardiovascular effects of lidocaine.
• Anticonvulsants: may lower seizure threshold when lidocaine levels rise.