Analgesic efficacy and haemodynamic effects of nefopam in critically ill patients

Background. Pain management is challenging in intensive care unit (ICU) patients. The analgesic efficacy, tolerance, and haemodynamic effects of nefopam have never been described in critically ill patients. Methods. In consecutive medical-surgical ICU patients who received 20 mg of nefopam i.v. over 30 min, we measured pain, Richmond Agitation Sedation Scale (RASS), respiratory parameters, and adverse drug events at T0 (baseline), T30 (end-of-infusion), T60, and T90 min. Haemodynamic variables were assessed every 15 min from T0 to T60 and T90. Pain was evaluated by the behavioural pain scale (BPS, 3-12) or by the self-reported visual numeric rating scale (NRS, 0-10) according to communication capacity. Results. Data were analysed for 59 patients. As early as T30, median NRS and BPS decreased significantly from T0 to a minimum level at T60 for NRS [5 (4-7) vs 1 (1-3), P < 0.001] and T90 for BPS [5 (5-6) vs 3 (3-4), P < 0.001]. No significant changes were detected for RASS, ventilatory frequency, or oxygen saturation. Increased heart rate and decreased mean arterial pressure, defined as a change >= 15% from baseline, were found in 29% and 27% of patients, respectively. For the 18 patients monitored, cardiac output increased by 19 (7-29)% and systemic vascular resistance decreased by 20 (8-28)%, both maximally at T30. Heat sensation, nausea/vomiting, sweating, and mouth dryness were found, respectively, in 6%, 9%, 22%, and 38% of patients. Conclusions. A single slow infusion of nefopam is effective in critically ill patients who have moderate pain. The risk of tachycardia and increased cardiac output and also hypotension and decreased systemic vascular resistance should be known to evaluate the benefit/risk ratio of its prescription.