Serum Concentration of Lignocaine After Pertubation: An Observational Study

OBJECTIVE The objective of this study was to report the serum concentration of lignocaine after pertubation in patients with endometriosis. DESIGN Prospective observational study. SETTING The study was carried out at a gynaecological outpatient unit in Stockholm, Sweden. POPULATION Eligible patients had endometriosis with a dysmenorrhoic pain score of >50 mm on a visual analogue scale, and patent fallopian tubes. METHODS Patients with endometriosis (n = 25) were included in the study. The patients received pre-ovulatory pertubations with lignocaine hydrochloride 10 mg (n = 16) or ringer acetate (placebo, n = 9). The procedure comprised passing the study solution through the uterus and the fallopian tubes via an intra-cervical balloon catheter. Serum samples were collected at 0, 5, 15 and 30 min after pertubation. MAIN OUTCOME MEASURES The serum samples were analysed for the concentration of lignocaine with an LCMS-SIM method. RESULTS Low levels of lignocaine were detected in the serum samples following pertubation of 10 mg lignocaine hydrochloride. The highest observed concentration was seen after 30 min (mean 0.050 μg/ml), with an individual maximum of 0.124 μg/ml. Maximum concentration (C max) and time to C max (T max) could not be calculated, since the highest values were observed in the 30-min samples, which was the last sample obtained. Lignocaine was not detected after pertubation with placebo. CONCLUSIONS The serum levels of lignocaine following pertubation of 10 mg lignocaine hydrochloride are detectable but low. Lignocaine pertubated through the fallopian tubes reaches the peritoneal cavity and diffuses through the peritoneum into the blood circulation. Pertubation with lignocaine is safe and has no lignocaine-related adverse events.