Sameridine Is Safe and Effective for Spinal Anesthesia

Lidocaine vs. Other Local Anesthetics in the Development of Transient Neurologic Symptoms (TNS) Following Spinal Anesthesia: A Meta-Analysis of Randomized Controlled Trials

The use of lidocaine in spinal anesthesia may increase the risk of transient neurological symptoms (TNS) according to previous meta-analyses. However, the previous meta-analyses lacked data on some other local anesthetics and thus, more evaluations are still needed to compare the effect of lidocaine on the development of TNS. The objective of this study was to compare the risk of TNS according to lidocaine versus other local anesthetics in patients undergoing spinal anesthesia. A total of 39 randomized controlled trials with 4733 patients were analyzed. The incidence of TNS was 10.8% in the lidocaine group and was 2.2% in the control groups (risk ratio (RR) 4.12, 95% confidence interval (CI) 3.13 to 5.43, p < 0.001). In subgroup analysis, lidocaine increased the incidence of TNS compared with other local anesthetics except mepivacaine, ropivacaine or sameridine. The risk of TNS was higher in the hyperbaric (p < 0.001) or isobaric lidocaine (p < 0.001) group compared with the control group, but there were no differences found between the two groups when hypobaric lidocaine was administered (p = 1.00). This study confirmed that lidocaine for spinal anesthesia still causes TNS more frequently than most other local anesthetics, especially when hyperbaric or isobaric lidocaine was used.

Hypercarbic and hypoxic ventilatory responses after intrathecal administration of bupivacaine and sameridine

Sameridine is a new compound with both local anesthetic and opioid properties (partial micro -opioid receptor agonist). It was intended for intrathecal administration to provide anesthesia for surgery and extended postoperative analgesia. In this double-blinded pharmacodynamic study with a two-parallel-group design, we investigated, during a 24-h period, the effects of intrathecal sameridine and bupivacaine on ventilation at rest and at ventilatory challenges during hypercarbia and hypoxia. Twenty-four healthy volunteers received either 25 mg of sameridine or 15 mg of bupivacaine intrathecally. Ventilation was measured by pneumotachography and in-line capnography. Sedation was rated by a visual analog scale. Segmental spread and development of motor and sensory block were similar in both groups. There was a decrease in tidal volume 2.5 to 6 h after injection in the bupivacaine group. This was seen only at 4 h in the sameridine group. There were no other major ventilatory differences between sameridine and bupivacaine during resting ventilation. Hypercarbic (tidal volume, mean inspiratory flow) and hypoxic (mean inspiratory flow) ventilatory responses were slightly decreased in the sameridine group, but not in the bupivacaine group. We conclude that intrathecal administration of sameridine or bupivacaine in healthy volunteers produces similar, minor effects on ventilatory responses over a 24-h observation period.

Determination of sameridine in blood plasma by nitrogen-selective gas chromatography

A gas chromatographic method was developed and validated for the determination of sameridine in human plasma. Sameridine is a new type of compound with both local anaesthetic and analgesic properties, when administered intrathecally. The method is based on liquid-liquid extraction of sameridine from 1.0 ml of plasma, followed by gas chromatography with nitrogen-phosphorus detection. Method validation results showed that this method is very sensitive, selective and robust. The limit of quantification was 1 nM for 1.0 ml of human plasma in the low-level range (1.00-75.0 nM) and the between-day accuracy and precision were measured at 99-104% of nominal values and 3.4-5.6% (RSD), respectively.