Instillido (Lidocaine Hydrochloride)

Lidocaine hydrochloride is a local anesthetic used to achieve temporary numbness of the urethra during urological procedures.

• Urethral diagnostic examinations (e.g., cystoscopy, urethroscopy): provides analgesia to reduce discomfort and facilitate examination.
• Urethral therapeutic interventions (e.g., dilation, stent placement): ensures patient tolerance and minimizes procedural pain.
• Minor urethral surgeries (e.g., laser ablation, biopsy): delivers localized anesthesia to improve surgical conditions.
• Urethral catheter insertion: reduces pain associated with catheter placement and improves patient compliance.
• Urethral irrigation or washout: provides comfort during fluid administration and helps maintain procedural tolerance.

• Lidocaine hydrochloride produces local anesthesia by reversibly binding to the intracellular portion of voltage‑gated sodium channels on neuronal membranes. This blockade prevents the influx of sodium ions during depolarization, thereby inhibiting the generation and propagation of nerve impulses. The effect is confined to the site of application, resulting in temporary loss of sensation without affecting consciousness.

Lidocaine hydrochloride may cause local or systemic adverse reactions, ranging from mild irritation to rare serious events.

Common Side Effects

• Burning sensation at the application site: brief, transient discomfort.
• Transient mild urethral irritation: redness or mild swelling that resolves quickly.
• Temporary urinary urgency or frequency: increased urge to void for a short period.
• Mild headache: occasional dull head pain not requiring treatment.

Serious or Rare Side Effects

• Allergic reaction (rash, angioedema, anaphylaxis): signs of hypersensitivity requiring immediate medical attention.
• Severe hypotension due to systemic absorption: marked drop in blood pressure, potentially leading to dizziness.
• Cardiac arrhythmia (e.g., ventricular ectopy): irregular heart rhythm that may need monitoring.
• Methemoglobinemia (rare): elevated methemoglobin levels causing cyanosis and reduced oxygen delivery.

When using Instillido, consider the following precautions to ensure safe and effective administration.

• Allergy assessment: confirm no known hypersensitivity to lidocaine or amide‑type anesthetics.
• Dosage verification: ensure the prescribed volume matches the procedural requirement and avoid excess.
• Systemic absorption risk: limit total administered amount, especially in patients with hepatic impairment.
• Concurrent CNS depressants: use with caution when combined with other local anesthetics or central nervous system depressants.
• Pregnancy and lactation: evaluate risk‑benefit, as safety data are limited for use during pregnancy or breastfeeding.
• Store at ambient temperature: keep in the original container, protect from light and moisture.

Lidocaine hydrochloride can interact with other medicines; awareness of major and moderate interactions helps prevent toxicity.

Major Interactions (Avoid)

• Class I antiarrhythmic drugs (e.g., quinidine, procainamide): may increase lidocaine plasma concentrations and toxicity.
• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): can reduce metabolism leading to elevated systemic levels.
• Concurrent use of other local anesthetics: additive neuro‑ and cardiotoxic effects.

Moderate Interactions (Monitor Closely)

• Beta‑blockers: may potentiate cardiac depressant effects of lidocaine.
• Diuretics: can alter plasma protein binding, affecting lidocaine distribution.
• General anesthetics (e.g., propofol, inhalational agents): monitor for enhanced central nervous system depression.