Instillagel (Chlorhexidine Gluconate, Lidocaine Hydrochloride)

Instillagel, containing chlorhexidine gluconate and lidocaine hydrochloride, is employed for urethral antisepsis and analgesia in urological settings.

• Urethral antisepsis: reduces bacterial colonisation and helps prevent urinary tract infection during catheterisation.
• Catheter‑related procedures: provides local analgesia to minimise discomfort during insertion of catheters or endoscopic instruments.
• Pre‑procedure preparation: cleans the urethral mucosa before diagnostic or therapeutic interventions, supporting aseptic technique.

• Chlorhexidine gluconate acts by binding to bacterial cell walls, disrupting membrane integrity and causing cell death, while lidocaine hydrochloride blocks voltage‑gated sodium channels on peripheral nerves, inhibiting impulse transmission and producing localized anesthesia. The combined action delivers both antimicrobial protection and pain relief at the site of urethral application.

Instillagel may cause local and systemic reactions. Patients should be aware of both common and rare adverse events.

Common Side Effects

• Mild urethral irritation or burning sensation.
• Transient redness or mild inflammation of the urethral mucosa.
• Temporary urinary urgency or frequency.
• Localized hypersensitivity rash.

Serious or Rare Side Effects

• Anaphylactic reaction presenting with hives, swelling, or respiratory distress.
• Severe urethral ulceration or chemical burns.
• Systemic lidocaine toxicity (e.g., dizziness, seizures, cardiac arrhythmia).
• Persistent severe pain or numbness beyond the procedure site.

Before using Instillagel, consider the following safety measures.

• Hypersensitivity: avoid if the patient has known allergy to chlorhexidine, lidocaine, or any formulation components.
• Open wounds: do not apply to damaged urethral tissue or active bleeding sites.
• Pregnancy and lactation: use only if clearly indicated and prescribed by a qualified clinician.
• Renal impairment: monitor patients with severe kidney dysfunction due to potential systemic absorption.
• Interaction with other topical antiseptics: limit concurrent use to reduce irritation risk.
• Store below 25°C: keep in the original container, protect from moisture and direct sunlight.

Instillagel can interact with other medications; awareness of major and moderate interactions helps ensure safe use.

Major Interactions (Avoid)

• Concurrent systemic lidocaine or other local anesthetics: risk of cumulative toxicity.
• Other chlorhexidine‑containing products applied to the same site: may increase mucosal irritation.
• Intravenous anti‑arrhythmic agents (e.g., procainamide): potential additive cardiac effects.

Moderate Interactions (Monitor Closely)

• Anticoagulants (e.g., warfarin): monitor for increased bleeding if mucosal injury occurs.
• Renally excreted drugs (e.g., aminoglycosides): observe for altered clearance if systemic absorption rises.
• NSAIDs: watch for enhanced local irritation when used together.