Instillido (Lidocaine Hydrochloride)

Instillido, a urethral local anesthetic, is employed to numb the urethral mucosa for various urological procedures.

• Urethral anesthesia: provides localized numbness for diagnostic or therapeutic procedures involving the urethra.
• Cystoscopic procedures: facilitates patient comfort during cystoscopy by reducing sensation.
• Urethral catheter insertion: minimizes discomfort and spasm during catheter placement.

• Lidocaine hydrochloride blocks voltage‑gated sodium channels on neuronal membranes, inhibiting the initiation and propagation of action potentials. This interruption of nerve impulse transmission results in loss of sensation in the area where the drug is applied, producing a rapid and reversible local anesthetic effect.

Lidocaine Hydrochloride may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Burning or stinging sensation at the application site.
• Transient numbness lasting several minutes.
• Mild urinary urgency or frequency.
• Dizziness or light‑headedness.

Serious or Rare Side Effects

• Allergic reactions such as rash, itching, or swelling.
• Severe hypotension or cardiovascular collapse.
• Methemoglobinemia leading to cyanosis.
• Seizures, cardiac arrhythmias, or respiratory depression.

When using Instillido, healthcare professionals should observe several safety measures to reduce risk.

• Allergy assessment: confirm no known hypersensitivity to amide‑type local anesthetics.
• Application site evaluation: avoid use on inflamed or infected mucosa.
• Cardiovascular monitoring: observe for signs of arrhythmia or hypotension in susceptible patients.
• Dosage limitation: adhere strictly to prescribed volume to prevent systemic toxicity.
• Concomitant CNS depressants: use with caution when patients are receiving other central nervous system depressants.
• Store at room temperature: keep below 25 °C, protect from moisture and direct light in the original packaging.

Lidocaine may interact with other medicines, altering its plasma concentration or enhancing pharmacologic effects.

Major Interactions (Avoid)

• Class I antiarrhythmics (e.g., quinidine, procainamide): can raise lidocaine levels and increase toxicity risk.
• CYP1A2 inhibitors (e.g., fluvoxamine): may reduce lidocaine metabolism.
• CYP3A4 inhibitors (e.g., ketoconazole, erythromycin): may elevate systemic exposure.
• Beta‑adrenergic blockers (e.g., propranolol): can potentiate cardiovascular depressant effects.

Moderate Interactions (Monitor Closely)

• Other local anesthetics: additive neuro‑ and cardiotoxicity.
• General anesthetics (e.g., propofol, volatile agents): may enhance central nervous system depression.
• Diuretics (e.g., furosemide): may affect plasma protein binding and increase free lidocaine.