Comparison of ramosetron with ondansetron for prevention of postoperative nausea and vomiting in patients undergoing gynaecological surgery.

BACKGROUND: Ramosetron is a new selective 5-hydroxytryptamine type 3 (5-HT(3)) receptor antagonist that reportedly has more potent antiemetic effects compared with other 5-HT(3) receptor antagonists. The purpose of this study was to evaluate the efficacy of ramosetron for the prevention of postoperative nausea and vomiting (PONV) with that of ondansetron or placebo in high-risk patients undergoing gynaecological surgery. METHODS: In this prospective, randomized, double-blinded, placebo-controlled study, 162 healthy patients who were undergoing gynaecological operation under general anaesthesia using sevoflurane were enrolled. Patients were divided into three groups: the ramosetron group (0.3 mg i.v.; n=54), the ondansetron group (8 mg i.v.; n=54), and the placebo group (normal saline i.v.; n=54). The treatments were given before the end of surgery. The incidence of PONV, severity of nausea, and the use of rescue antiemetic requirements during the first 24 h after surgery were evaluated. RESULTS: The incidence of nausea was lower in the ramosetron (50%) and ondansetron (44%) groups compared with the placebo group (69%) (P<0.05). In addition, the incidence of vomiting was lower in both the ramosetron (17%) and the ondansetron (20%) groups than in the placebo group (44%) during the first 24 h after surgery (P<0.05). The visual analogue scale score for nausea was also lower in the ramosetron and ondansetron groups compared with the placebo group (P<0.05). The proportion of patients requiring rescue antiemetics was significantly lower with ramosetron (15%) when compared with the placebo group (41%) during the 24 h after surgery (P<0.05). However, there were no significant differences in the incidence of nausea and vomiting, severity of nausea, and required rescue PONV between the ramosetron and the ondansetron groups. CONCLUSIONS: Ramosetron 0.3 mg i.v. was as effective as ondansetron 8 mg i.v. in decreasing the incidence of PONV and reducing nausea severity in female patients during the first 24 h after gynaecological surgery.

Discrepancy of recovery times related to potency between atracurium and mivacurium simultaneously administered in isolated forearms.

Recovery from potent non-depolarising muscle relaxants is slower than from the less potent agents. However, recovery from mivacurium, which is more potent than atracurium, is faster than from atracurium following systemic administration. In an attempt to confirm this discrepancy we compared recovery times following simultaneous administration of equipotent doses of atracurium and mivacurium into the isolated forearms of human volunteers (n = 10). This method enabled us to study the interaction of muscle relaxants with receptors at the neuromuscular junction separated from the effects of plasma drug concentration. In these experiments, the recovery times from maximum block to 50% recovery of control twitch height were significantly longer with mivacurium than with atracurium (mean 25.2(SD 4.7) versus 22.6(3.1) min, p < 0.01). We found that the evidence that mivacurium has a slower recovery than the less potent atracurium may be true using the bilateral, isolated forearm technique and that the discrepancy might be due to a difference in the pharmacokinetic variables of the two drugs.