Ciprofol is a new intravenous anesthetic agent similar to propofol that has the pharmacodynamic characteristics of a rapid rate of onset and recovery in pre-clinical experiments. The aims of the present clinical trials were to compare the efficacy and safety of ciprofol emulsion for sedation or general anesthesia during colonoscopy and to define optimal doses for a subsequent phase III clinical trial. A phase IIa multi-center, open-label, non-randomized, positive control, dose-escalating study was performed to determine a recommended phase IIb dose (RP2D) of ciprofol to induce sedation or anesthesia in patients undergoing colonoscopy. Phase IIb was also a multi-center clinical trial, but the patients were randomized into 3 groups at a ratio of 1:1:1. It was a double-blinded, propofol controlled study that administered ciprofol 0.4 mg/kg (n = 31) and 0.5 mg/kg (n = 32) or propofol at 2.0 mg/kg (n = 31), with the aim of establishing the optimal dose of ciprofol. The primary endpoint was the colonoscopy success rate. Secondary endpoints were the duration of colonoscope insertion, recovery time, number of top-up doses needed, and the total dose of ciprofol or propofol required to maintain adequate sedation or anesthesia. In addition, we evaluated the satisfaction of sedation/anesthesia from the endoscopists, anesthetists and patients' points of view. Safety was assessed according to the incidence of AEs including serious AEs and drug related AEs and the assessment of vital signs, a 12-lead ECG and laboratory tests. In the phase IIa trial, the colonoscopy success rates in the 0.2-0.5 mg/kg ciprofol and propofol 2.0 mg/kg groups were 100% and all doses were safe and well tolerated. Ciprofol doses of 0.4 mg/kg and 0.5 mg/kg are recommended for subsequent IIb phases. In the phase IIb trial, a 100% success rate was reconfirmed in all the dosage groups. The mean time of colonoscope insertion in the ciprofol 0.4 mg/kg, ciprofol 0.5 mg/kg and propofol 2.0 mg/kg groups were 1.9, 1.5 and 1.5 min, the mean recovery times from colonoscope withdrawal were 6.1, 5.1, and 4.3 min, and the times to discharge were 11.8, 11.2 and 10.6 min, respectively. The satisfaction ratings of anesthetists in the ciprofol 0.5 mg/kg group (9.5 ± 0.8) were higher than in the ciprofol 0.4 mg/kg (9.2 ± 1.0) and propofol 2.0 mg/kg (9.2 ± 0.9) groups. The incidence of sedation and anesthesia-related AEs was highest in the propofol 2.0 mg/kg group (25.8%), followed by the ciprofol 0.5 mg/kg group (21.9%), and was least in the ciprofol 0.4 mg/kg group (16.1%) (P = 0.750). Ciprofol was safe and well tolerated at doses ranging from 0.1 mg/kg to 0.5 mg/kg. Ciprofol 0.4-0.5 mg/kg induced equivalent sedation/anesthesia and had a similar safety profile to propofol 2.0 mg/kg during colonoscopy without producing serious AEs.

Ciprofol is a propofol analogue with improved pharmacokinetic properties. A multi‐centre, non‐inferiority trial was conducted to compare the deep sedation properties of ciprofol and propofol with a non‐inferiority margin of 8% in patients undergoing gastroscopy and colonoscopy. In total, 289 patients were randomly allocated for surgery (259 colonoscopy and 30 gastroscopy) at a 1:1 ratio to be given intravenous injections of ciprofol (0.4 mg/kg) or propofol (1.5 mg/kg). The primary outcome was the success rate of colonoscopy defined as colonoscopy completion with no need for an alternative sedative or >5 ciprofol or propofol top up doses within any 15‐min time period. The success rate of colonoscopy was 100% in the ciprofol group vs. 99.2% in the propofol group (mean difference 0.8%, 95% CI: −2.2% to 4.2%). Except for the gastrointestinal lesions found during the gastroscopy and colonoscopy procedures, the occurrence rates of adverse drug reactions in the ciprofol and propofol groups were 31.3% and 62.8%, respectively (P < 0.001). Pain on injection was less common in the ciprofol group (4.9% vs. 52.4%, P < 0.001). The outcomes demonstrated that ciprofol was non‐inferior to propofol with regard to successful sedation for gastroscopy or colonoscopy procedures and no obvious important adverse events occurred.

To provide an overview of phantom limb pain (PLP) in China. This includes the prevalence of PLP and possible risk factors. In a retrospective study, telephone interviews were conducted with 391 amputation patients who underwent extremity amputations at a tertiary hospital in China. PLP was found in 29% of the amputees. Pre-amputation pain (OR = 10.4, P = 0.002) and postoperative analgesia (OR = 4.9, P = 0.008) were identified as high-risk factors for PLP. 82.1% of PLP patients experienced pre-amputation pain. The average pain intensity of PLP was 5.1 ± 2.2, with 31.9% having severe intensity. The effects of PLP on the quality of the PLP patients were as follows: 7.8% of the patients had to limit their daily life and 29.0% of the patients had to limit their social activities. 17.3 and 25.7% of patients experienced depression and sleeping disorder respectively, while 18.9% had loss of interest and even 16.1% of PLP patients had attempted suicide. No effective treatments were found in 78.9% of these patients. PLP has markedly affected the lives of patients. Pre-amputation pain and postoperative epidural analgesia might be risk factors for the phantom limb pain after amputation. Prevention of pre-amputation pain and sudden post-amputation deafferentation should be recommended to the amputees.

Morphine-induced hyperalgesia and tolerance significantly limits its clinical use in relieving acute and chronic pain. Melatonin, a pineal gland neurohormone, has been shown to participate in certain neuropsychopharmacological actions. The present study investigated the effect of melatonin on morphine-induced hyperalgesia and tolerance and possible involvement of protein kinase C (PKC)/N-methyl-D-aspartate (NMDA) pathway in melatonin-mediated.