Instillido (Lidocaine Hydrochloride)

Instillido, a lidocaine formulation, is applied to the urethral mucosa to facilitate painless urological procedures.

• Cystoscopy: provides local anesthesia to reduce discomfort during visual examination of the bladder and urethra.
• Urethral catheter insertion: numbs the urethra to allow smooth catheter placement with minimal pain.
• Urethral dilation: eases the passage of dilators during treatment of strictures.
• Transurethral procedures: offers temporary anesthesia for minor interventions such as biopsy or stent placement.

• Lidocaine Hydrochloride blocks voltage‑gated sodium channels on neuronal membranes, preventing the initiation and propagation of action potentials. By stabilizing the neuronal membrane, it inhibits the transmission of pain signals from the urethral mucosa, resulting in localized loss of sensation without affecting systemic nerve function.

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

Common Side Effects

• Burning or stinging sensation at the application site.
• Mild local irritation or redness.
• Transient numbness lasting several minutes.
• Light‑headedness or mild dizziness.
• Headache.
• Nausea.

Serious or Rare Side Effects

• Allergic reactions such as rash, itching, or swelling.
• Severe hypotension or cardiovascular collapse.
• Cardiac arrhythmias, including ventricular tachycardia.
• Seizures or central nervous system toxicity.
• Methemoglobinemia.
• Respiratory depression.

When using Instillido, several safety considerations should be observed.

• Allergy assessment: verify no known hypersensitivity to lidocaine or amide‑type anesthetics.
• Dosage control: adhere strictly to prescribed volume to avoid systemic toxicity.
• Patient monitoring: observe for signs of cardiovascular or neurologic adverse effects during and after administration.
• Caution in cardiac disease: use carefully in patients with existing heart conduction abnormalities.
• Avoid concurrent use of other local anesthetics to reduce cumulative toxicity risk.
• Store at room temperature: keep in original packaging, protect from moisture and direct sunlight.

Lidocaine can interact with several drug classes, influencing its safety profile.

Major Interactions (Avoid)

• Other amide local anesthetics: increase risk of systemic toxicity.
• Class I antiarrhythmics (e.g., quinidine, procainamide): may potentiate cardiac conduction disturbances.
• CYP1A2 or CYP3A4 inhibitors (e.g., cimetidine, erythromycin): raise plasma lidocaine levels.

Moderate Interactions (Monitor Closely)

• Beta‑blockers: may enhance bradycardic effects.
• Diuretics (e.g., furosemide): can lower plasma protein binding, increasing free lidocaine.
• Anticonvulsants: potential additive CNS depression.
• Alcohol: may augment sedative properties.
• Herbal supplements affecting CYP enzymes (e.g., St. John’s wort): alter lidocaine metabolism.