Instillido (Lidocaine Hydrochloride)

Instillido, a urethral local anesthetic, is employed to numb the urethral mucosa during various urological interventions.

• Cystoscopy: provides local numbness to facilitate examination of the bladder and urethra.
• Catheter insertion: reduces discomfort during placement of urinary catheters.
• Transurethral procedures: enables pain‑free therapeutic interventions such as resection or dilation.

• Lidocaine hydrochloride reversibly blocks voltage‑gated sodium channels on neuronal membranes, preventing the initiation and propagation of nerve impulses. By inhibiting sodium influx, it stabilises the neuronal membrane and produces a rapid, localized loss of sensation without affecting systemic consciousness.

Instillido may cause a range of adverse reactions following urethral administration.

Common Side Effects

• Burning or stinging sensation at the application site
• Mild urethral irritation or discomfort
• Transient numbness lasting several minutes
• Urinary urgency or frequency
• Light‑headedness or mild headache

Serious or Rare Side Effects

• Allergic reaction including anaphylaxis
• Severe hypotension or cardiovascular collapse
• Cardiac arrhythmias such as ventricular tachycardia
• Methemoglobinemia leading to cyanosis
• Seizures or central nervous system toxicity
• Persistent numbness beyond the expected duration

Before using Instillido, several safety considerations should be observed.

• Assess allergy: confirm the patient has no known hypersensitivity to lidocaine or related amide anesthetics.
• Use minimal effective volume: limit exposure to the urethral mucosa to reduce systemic absorption.
• Monitor vital signs: observe for hypotension, bradycardia, or arrhythmias during and after administration.
• Avoid concurrent systemic local anesthetics: concurrent use may increase the risk of cumulative toxicity.
• Pregnancy and lactation: use only if the anticipated benefit outweighs potential risk to the fetus or infant.
• Store at room temperature: keep in the original container, protect from moisture and light.

Instillido can interact with other medicines, requiring attention to avoid adverse outcomes.

Major Interactions (Avoid)

• Class I antiarrhythmic drugs (e.g., quinidine, procainamide): additive cardiotoxicity risk.
• Beta‑blockers (e.g., propranolol): may enhance lidocaine’s cardiac depressant effects.
• Strong CYP3A4 inhibitors (e.g., ketoconazole): increase systemic lidocaine exposure.

Moderate Interactions (Monitor Closely)

• Other local anesthetics: cumulative toxicity potential.
• Epinephrine: may alter lidocaine absorption and cardiovascular response.
• Diuretics (e.g., furosemide): may affect plasma protein binding and increase free drug levels.