[Prevention of postoperative nausea and vomiting with single and repeat administration of ondansetron--review of the literature on different administration forms].

Postoperative nausea and vomiting (PONV) is still a common perioperative complication and ondansetron has proved to be an effective antiemetic substance in its prevention. The antiemetic effect of single and repetitive application was evaluated in this study. Fifty-one female patients who underwent gynaecological surgical procedures took part in a random double-blind study. Before the start of anaesthesia, 21 patients (group 1) received either a placebo (six patients), 8 mg ondansetron orally (seven patients) or 16 mg orally (eight patients). The remaining 30 patients (group 2), split into subgroups of ten, were given the same preoperative medication as group 1 plus further doses of the same strength 8 and 16 hours after the first intake of the study medication. Metoclopramide was given intravenously if patients had more than one emetic episode or if they asked for it. Nausea and vomiting were documented up to 24 hours after finishing anaesthesia. Metoclopramide had only to be given to patients who had received a placebo. Nausea was felt by 57% (4/7) of the patients after a single dose of 8 mg ondansetron and by 40% (4/10) of the patients after three doses of 8 mg. One patient (14%, 1/7) with a single dose and two patients (20%, 2/10) with a repetitive dose of 8 mg ondansetron vomited. Following a single dose of 16 mg ondansetron, no patient (0/8) had to vomit and 25% (2/8) of the patients had nausea. There were no complications reported by the patients. Ondansetron was shown to be a well-tolerated antiemetic and seems to have a higher reductive effect on PONV when given in a single dose and not repetitively. The prophylaxis of vomiting seems to be more effective than the reduction of nausea. Follow-up studies will have to clarify our findings.