Remifentanil Hydrochloride for injection has been studied in the monitored anesthesia care setting in 609 patients in eight clinical studies. Nearly all patients received supplemental oxygen in these studies. Two early dose-finding studies demonstrated that use of sedation as an endpoint for titration of Remifentanil Hydrochloride for injection led to a high incidence of muscle rigidity (69%) and respiratory depression. Subsequent trials titrated Remifentanil Hydrochloride for injection to specific clinical endpoints of patient comfort, analgesia, and adequate respiration (respiratory rate > 8 breaths/min) with a corresponding lower incidence of muscle rigidity (3%) and respiratory depression. With doses of midazolam > 2 mg (4 to 8 mg), the dose of Remifentanil Hydrochloride for injection could be decreased by 50%, but the incidence of respiratory depression rose to 32%.

The efficacy of a single dose of Remifentanil Hydrochloride for injection (1.0 mcg/kg over 30 seconds) was compared to alfentanil (7 mcg/kg over 30 seconds) in patients undergoing ophthalmic surgery. More patients receiving Remifentanil Hydrochloride for injection were pain free at the time of the nerve block (77% versus 44%, P = 0.02) and more experienced nausea (12% versus 4%) than those receiving alfentanil.

In a randomized, controlled study (n = 118), Remifentanil Hydrochloride for injection 0.5 mcg/kg over 30 to 60 seconds followed by a continuous infusion of 0.1 mcg/kg/min, was compared to a propofol bolus (500 mcg/kg) followed by a continuous infusion (50 mcg/kg/min) in patients who received a local or regional anesthetic nerve block 5 minutes later. The incidence of moderate or severe pain during placement of the block was similar between groups (2% with Remifentanil Hydrochloride for injection and 8% with propofol, P = 0.2) and more patients receiving Remifentanil Hydrochloride for injection experienced nausea (26% versus 2%, P < 0.001). The final mean infusion rate of Remifentanil Hydrochloride for injection was 0.08 mcg/kg/min.

In a randomized, double-blind study, Remifentanil Hydrochloride for injection with or without midazolam was evaluated in 159 patients undergoing superficial surgical procedures under local anesthesia. Remifentanil Hydrochloride for injection was administered without midazolam as a 1 mcg/kg dose over 30 seconds followed by a continuous infusion of 0.1 mcg/kg/min. In the group of patients that received midazolam, Remifentanil Hydrochloride for injection was administered as a 0.5 mcg/kg dose over 30 seconds followed by a continuous infusion of 0.05 mcg/kg/min and midazolam 2 mg was administered 5 minutes later. The occurrence of moderate or severe pain during the local anesthetic injection was similar between groups (16% and 20%). Other effects for Remifentanil Hydrochloride for injection alone and Remifentanil Hydrochloride for injection /midazolam were: respiratory depression with oxygen desaturation (SPO2 < 90%), 5% and 2%; nausea, 8% and 2%; and pruritus, 23% and 12%. Titration of Remifentanil Hydrochloride for injection resulted in prompt resolution of respiratory depression (median 3 minutes, range 0 to 6 minutes). The final mean infusion rate of Remifentanil Hydrochloride for injection was 0.12 mcg/kg/min (range 0.03 to 0.3) for the group receiving Remifentanil Hydrochloride for injection alone and 0.07 mcg/kg/min (range 0.02 to 0.2) for the group receiving Remifentanil Hydrochloride for injection /midazolam.