Indigo Carmine Visualization Duration in Urine: A Randomized Kinetics Study

Area of Science:

• Pharmacology
• Urology
• Clinical Trials

Background:

• Indigo carmine is frequently used for visualizing ureteral efflux during surgery.
• Limited data exist on indigo carmine pharmacokinetics and urine color duration.
• Understanding persistence aids accurate intraoperative urinary system assessment.

Purpose of the Study:

• To observe plasma and urinary pharmacokinetics of indigo carmine in healthy volunteers.
• To determine the duration of blue color in voided urine after indigo carmine administration.

Main Methods:

• Open-label, randomized clinical trial with 16 healthy participants.
• Intravenous injection of either 2.5-mL or 5.0-mL indigo carmine.
• Collection of blood and urine samples at various time points post-injection; stool collection.

Main Results:

• Plasma concentration peaked within 5 minutes, with elimination below quantification by 2 hours.
• Estimated plasma half-life of indigo carmine was 12 minutes.
• Urine discoloration persisted up to 6 hours in 10/16 participants and 12 hours in 1/16.

Conclusions:

• Short half-life and rapid urinary excretion support indigo carmine's clinical utility.
• Findings align with the typical time to ureteral efflux observed during surgery.
• Supports its use for intraoperative cystoscopy and urinary tract assessment.