URETHRAL ANESTHESIA WITH TOPICAL BUPIVACAINE - A ROLE FOR A LONGER-ACTING AGENT

Objective To assess the efficacy and toxicity of bupivacaine as a topi cal urethral anaesthetic. Patients and methods This prospective two-pa rt study comprised a pilot study of 10 men (mean age 73 years, range 3 9-86), to determine the toxicology, pharmocokinetics and suitable prep aration of bupivacaine gel, and a study of 40 men (mean age 76 years, range 59-92) to compare the efficacy of bupivacaine with lignocaine ge l, All patients were undergoing treatment for benign prostatic hyperpl asia by transurethral radiofrequency heating using the Direx Thermex I I system. Results There were no major adverse events, Bupivacaine prov ided good topical anaesthesia with a mean duration of 141 min, compare d with 29 min for lignocaine, Serum samples taken from patients showed that the drug was absorbed slowly, and with a dose of 50 mg there was a wide margin between serum drug concentrations and toxic levels. Con clusion Bupivacaine is safe and effective as a topical anaesthetic age nt in the urethra in circumstances where prolonged duration of action is desirable, For lower urinary tract procedures 20-22 mt of anaesthet ic gel is required, giving 2-3 h of analgesia/anaesthesia with no sign ificant toxicity or adverse effect, The application of longer-acting a naesthetic agents need not be only during surgical intervention, but m ight usefully be extended post-operatively to provide early management of pain.