An assessment of droperidol as a premedicant

Anesthetic premedication: new horizons of an old practice

The practice of anesthetic premedication embarked upon soon after ether and chloroform were introduced as general anesthetics in the middle of the 19(th) century. By applying opioids and anticholinergics before surgery, the surgical patients could achieve a less anxious state, and more importantly, they would acquire a smoother course during the tedious and dangerous induction stage. Premedication with opioids and anticholinergics was not a routine practice in the 20(th) century when intravenous anesthetics were primarily used as induction agents that significantly shorten the induction time. The current practice of anesthetic premedication has evolved into a generalized scheme that incorporates several aspects of patient care: decreasing preoperative anxiety, dampening intraoperative noxious stimulus and its associated neuroendocrinological changes, and minimizing postoperative adverse effects of anesthesia and surgery. Rational use of premedication in modern anesthesia practice should be justified by individual needs, the types of surgery, and the anesthetic agents and techniques used. In this article, we will provide our readers with updated information about premedication of surgical patients with a focus on the recent application of second generation serotonin type 3 antagonist, antidepressants, and anticonvulsants.

Efficacy, dose-response, and adverse effects of droperidol for prevention of postoperative nausea and vomiting

PURPOSE

To estimate the efficacy and harm produced by droperidol in the prevention of postoperative nausea and vomiting (PONV).

METHODS

Systematic search (MEDLINE, EMBASE, Cochrane library, hand-searching, bibliographies, all languages, up to May 1999) for randomised comparisons of droperidol with placebo in surgical patients. Relevant end points were prevention of early PONV (up to six hours postoperatively), and late PONV (24 hr), and adverse effects. Combined data were analysed using relative risk and NNT.

RESULTS

In 76 trials, 5,351 patients received 24 different regimens of droperidol. The average incidence of early and late PONV in controls was 34% and 51%, respectively. Droperidol was more efficacious than placebo in preventing PONV. In adults, the anti-nausea effect was short-lived, and there was no dose-responsiveness; with 0.25 to 0.30 mg the number-needed-to-treat (NNT) to prevent early nausea was 5. For both early and late anti-vomiting efficacy there was dose-responsiveness; best efficacy was with 1.5 mg to 2.5 mg (NNT, 7). In children, there was dose-responsiveness; best efficacy was with 75 microg x kg(-1) (NNT to prevent early and late vomiting, 4). Two children had extrapyramidal symptoms with droperidol (NNT in children, 91; in any patient, 408). There was dose-responsiveness for sedation and drowsiness (with 2.5 mg the NNT was 7.8). Droperidol prevented postoperative headache (NNT, -25).

CONCLUSIONS

Droperidol is anti-emetic in the surgical setting. The effect on nausea is short-lived but more pronounced than the effect on vomiting. Sedation and drowsiness are dose-dependent, extrapyramidal symptoms are rare, and there is a protective effect against headache.

Neurological and psychiatric adverse effects of anaesthetics: epidemiology and treatment

The practice of anaesthesia has changed considerably over the past 20 to 30 years owing largely to technological advances in patient monitoring and an expanded and improved pharmacological repertoire. While patient safety in anaesthesia has greatly improved, the risk of neurological and psychiatric adverse effects of anaesthetics remains and is the focus of continued investigation. For example, a great deal of attention has recently been directed at intraoperative awareness. This adverse event can be caused by delivering an inappropriate amount or type of anaesthetic. Another risk of anaesthesia involves drug-induced unpleasant subjective states in patients. Those drugs most frequently associated with these states include ketamine, droperidol and scopolamine. This risk can often be attenuated by careful adjustment of drug dose and the use of adjunctive agents such as benzodiazepines which may produce amnesia of the unpleasant subjective state. While it is well established that modern anaesthetic drugs cause acute impairment of cognition and psychomotor functioning, there is little evidence that these drugs have long term impairing effects. Finally, a particular kind of surgery, cardiac surgery requiring cardiopulmonary bypass, can be associated with adverse neurological and psychiatric sequelae which, while not directly related to anaesthesia, are of intense interest to anaesthesiologists.

Nausea and vomiting after prostaglandins in day case termination of pregnancy. The efficacy of low dose droperidol

The antiemetic effects of low dose droperidol (0.25 and 0.5 mg) and a placebo were compared in patients who had received prostaglandin for day case termination of pregnancy. The incidence of nausea and vomiting was high. Low dose droperidol significantly reduced postoperative nausea and vomiting without any delay in immediate recovery or discharge home (p less than 0.05). Droperidol 0.25 mg was equally effective as an antiemetic, as 0.5 mg.

Midazolam versus fentanyl/droperidol and placebo as intramuscular premedicant

Midazolam, a new short-acting benzodiazepine with promising premedicant effects, was investigated in a double-blind, randomized clinical trial in 203 patients versus fentanyl/droperidol and placebo. Subjective effects, side-effects, amnesia and overall satisfaction were recorded. Midazolam caused the greatest decrease in anxiety level, and while causing more confusion and somnolence than placebo, caused less confusion and somnolence than fentanyl/droperidol. Half the patients who received midazolam reported anterograde amnesia. No serious side-effects were reported. Patient satisfaction was greater in the midazolam group than in the other groups.

Nausea and vomiting in day-case dental anaesthesia. The use of low-dose droperidol

The anti-emetic effects of low-dose droperidol (1.25 mg), ultra-low-dose droperidol (0.25 mg) and a placebo were compared in patients admitted for day-case dental anaesthesia. Ultra-low-dose droperidol produced a significant decrease in the subjective feeling of nausea without delaying recovery or discharge from the hospital (p less than 0.05). Low-dose droperidol did not significantly reduce nausea (p greater than 0.05) and prolonged the recovery time (p less than 0.05).

Droperidol (Dehydrobenzperidol): postoperative anti-emetic effect when given intravenously to gynaecological patients

In a double-blind investigation, comprising 300 gynaecological patients, the prophylactic use of droperidol i.v. at the start of the anaesthesia produced significant reduction in the frequency of nausea and vomiting postoperatively in the first 24 h from 34.4% to 10.3% (P=0.0001). There was no significant difference between the effect of droperidol 2.5 mg and 5 mg (P=0.45). Increased postoperative sedation was the only side-effect of any importance observed; however, this did not result in any increased period of observation in the recovery room, and the majority of patients considered it advantageous. Droperidol is recommended as a prophylactic anti-emetic for selected groups of patients, given as 2.5 mg i.v. at the start of the anaesthesia.

The postanesthetic antiemetic effect of premedication with dehydrobenzperidol before ether anesthesia

A study was performed to evaluate the antiemetic effects after ether anesthesia when dehydrobenzperidol (DHB) and pentobarbital were used for premedication and to compare these effects with halthane anesthesia when pentobarbital was used as premedication. Eighty-four patients undergoing minor surgical operations were randomly divided into three groups. The patients received ether and ether DHB 0.2 mg/kg or pentobarbital 2 mg/kg for premedication, or halothane and pentobarbital 2 mg/kg for premedication. The complaints of nausea and vomiting were recorded 24 h after anesthesia. We found that DHB compared to pentobarbital had a greater antiemetic effect after ether anesthesia, but the difference was not significant (P greater than 0.05). However, if only persistent nausea and vomiting were considered, the difference was significant (P less than 0.05). The incidence of nausea/vomiting after ether anesthesia with DHB as premedication was a little higher compared to halothane anesthesia with pentobarbital as premedication, but the difference was not significant (P greater than 0.05). However, if only persistent nausea/vomiting was considered, the incidence of complaints was equal in the two groups. It is concluded that when used for premedication to ether anesthesia DHB seems to lead to less postanesthetic nausea/vomiting than pentobarbital. Further DHB seems able to reduce the incidence of nausea/vomiting after ether anesthesia roughly to the level of that seen after pentobarbital premedication for halothane anesthesia.