Instillido (Lidocaine Hydrochloride)

Instillido, a local anesthetic acting on peripheral nerves of the urethra, is employed for several urological procedures.

• Urethral anesthesia for diagnostic or therapeutic procedures: provides localized numbness to enable painless examination or treatment.
• Pain relief during catheterization: reduces discomfort associated with urinary catheter insertion.
• Urethral anesthesia for transurethral interventions: facilitates patient comfort during endoscopic surgeries.

• Lidocaine Hydrochloride reversibly blocks voltage‑gated sodium channels on neuronal membranes, preventing the initiation and propagation of nerve impulses. By stabilizing the neuronal membrane, it inhibits depolarization, resulting in a temporary loss of sensation in the area where it is applied.

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

Common Side Effects

• Burning or stinging sensation at the application site
• Transient local numbness lasting longer than the procedure
• Mild urinary urgency or frequency
• Mild headache
• Dizziness or light‑headedness
• Mild irritation or erythema of the urethral mucosa

Serious or Rare Side Effects

• Allergic reaction including rash, itching, or swelling
• Severe hypotension or cardiovascular collapse
• Methemoglobinemia
• Cardiac arrhythmias
• Seizures or central nervous system toxicity
• Systemic lidocaine toxicity presenting as confusion or respiratory depression

Before using Instillido, consider the following safety measures.

• Allergy assessment: confirm the patient has no known hypersensitivity to lidocaine or related amide anesthetics.
• Dosage determination: follow the prescriber's specific instructions for volume and concentration.
• Cardiac disease: use with caution in patients with existing cardiac conduction abnormalities.
• Pregnancy and lactation: evaluate risk‑benefit ratio and consider alternative approaches when possible.
• Systemic absorption: monitor for signs of toxicity, especially with large volumes or repeated applications.
• Store at room temperature: keep in the original container, protect from light and moisture.

Lidocaine may interact with other medications, affecting its safety profile.

Major Interactions (Avoid)

• Class I antiarrhythmics (e.g., quinidine, procainamide): can increase plasma lidocaine levels and risk toxicity.
• Strong CYP3A4 inhibitors (e.g., ketoconazole, erythromycin): may elevate systemic exposure.

Moderate Interactions (Monitor Closely)

• Beta‑blockers: may enhance lidocaine’s cardiac depressant effects.
• Concurrent use of other local anesthetics: additive risk of systemic toxicity.
• Diuretics: may alter lidocaine plasma concentration and clearance.