Efficacy and tolerability of ready-to-use intravenous paracetamol solution as monotherapy or as an adjunct analgesic therapy for postoperative pain in patients undergoing elective ambulatory surgery: open, prospective study

Summary Aims: Paracetamol (acetaminophen) is one of the most widely used drugs for analgesia. We aimed to investigate the use of a ready-to-use intravenous (i.v.) paracetamol 1 g solution (Perfalgan®) as monotherapy or as adjunct therapy in patients undergoing elective ambulatory surgery. Methods: Open, non-controlled, observational study in six centres. Anaesthesiologists applied paracetamol 1 g intravenously about 30 min before the planned end of surgery and followed the patients up who reported postoperative pain visual analogue scale (VAS 0 mm minimum, 100 mm maximum) for pain rating until discharge (mean 123 ± 58 min). Results: A total of 601 patients (58.7% female patients, mean age 46.7 ± 15.4 years; 54% and 42% in American Society of Anesthesiologists ASA class I or II respectively) undergoing minor knee surgery (71.4%), minor gynaecological procedures (19.0%) or varicose vein surgery (9.6%) were included, of whom 590 patients received one i.v. infusion. Mean duration of surgery was 37 ± 21 min. Analgesic concomitant medication was applied in 57%. Mean self-reported pain intensity on the VAS was 33.2 at 15 min after end of surgery and was reduced to 19.2 at patient discharge (−13.9 points). Relative pain reduction was similar in the three surgery subtypes. The majority of patients achieved a VAS score