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.

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 < 30 mm and were classified as responders; i.v. paracetamol was well tolerated and no serious adverse events and only one possibly drug-related adverse event was reported. The majority of physicians (80.5%) and patients (81.6%) rated the efficacy, and satisfaction with therapy respectively, as very good or good.

CONCLUSIONS: Ready-to-use i.v. paracetamol, used as monotherapy or in combination with other analgesics, may be effective for alleviating postoperative pain and well tolerated in patients undergoing ambulatory surgery.