The use of lignocaine to reduce pain on i.v. injection of diluted nalbuphine.

A randomized, placebo-controlled, double-blind study was conducted on 66 healthy patients aged 10-61 years undergoing elective ear, nose and throat surgery to assess the incidence and severity of pain associated with intravenous (i.v.) injection of diluted nalbuphine HCl given during induction of general anaesthesia, and to determine the efficacy of adding lignocaine (2 mg mL-1) to nalbuphine to reduce this pain. Injection of saline produced pain of low intensity in 15% of patients and a withdrawal response in 3% of patients. Injection of nalbuphine mixed with lignocaine produced a significantly higher incidence (36%; P < 0.025) and severity (P < 0.025) of pain than saline, but a similar number of responses (6%) to pain. The diluted nalbuphine alone produced the highest incidence (61%) of pain (P < 0.01 vs. saline, P = NS vs. nalbuphine with lignocaine), which was most severe (P < 0.01 vs. saline, P < 0.025 vs. nalbuphine with lignocaine), and caused the highest number (27%) of withdrawal responses (P < 0.01 vs. saline, P < 0.025 vs. nalbuphine with lignocaine). We conclude that diluted nalbuphine 2 mg mL-1 produces pain on i.v. injection into peripheral veins, and that this can be significantly reduced by adding lignocaine 2 mg mL-1 to the solution.