EFFECT OF LIDOCAINE JELLY ON THE URETHRAL SENSORY THRESHOLD

In a randomized, double-blind, placebo controlled cross-over study the effect of lubricant with 2 % lidocaine versus lubricant without lidocaine was investigated by measuring the sensory threshold of the male urethra in healthy volunteers. In a first series (n = 12) with 1 minute latency between application of the lubricant and insertion of the transurethral catheter, there was a moderate effect of lidocain-jelly on the sensory thresholds in the penile and bulbar urethra and a poor effect in the prostatic urethra. In a second series (n = 9) with ten minutes latency between application of the lubricant and insertion of the catheter, there was a marked effect on the sensory thresholds in the penile and bulbar urethra and no effect in the prostatic urethra. Lidocaine jelly had a marked effect on the sensory threshold as compared to lubricant without lidocaine only in the series with 10 minutes latency but hat in the series with 1 minute latency. This is explained by displacement of the lubricant during insertion of the catheter. The lack of efficacy in the prostatic urethra is explained by a sort time only, by which the mucosa is exposed to the lidocaine-jelly.