Early and Late Effects of Nefopam in Multimodal Analgesia After Total Hip Arthroplasty (NEFARTHRO)

20 mg nefopam in 50 ml of saline, during a 30 min infusion, before end of procedure, then a similer bolus every 4 h for 24 h (6 injections in total) + continuous intravenous infusion of placebo (2 mL/h saline)

20 mg nefopam in 50 ml of saline, during a 30 min infusion, before end of procedure, then a bolus of placebo every 4 h for 24 h (6 injections in total) + continuous infusion of 100 mg nefopam over 24 h (in 48 mL saline, 2 mL/h)

50 ml of saline, during a 30 min infusion, before end of procedure, followed by a bolus of placebo every 4 hours for 24 hours (6 injections in all) + continuous infusion of placebo (2 mL/h of physiological saline)