Antiemetic therapy for nausea and vomiting in the emergency department.

BACKGROUND: Antiemetic agents are among the most frequently prescribed medications in the emergency department (ED). Nevertheless, there are no widely accepted evidence-based guidelines to optimize the use of these medications for nausea or vomiting in this setting. OBJECTIVE: The objective of this article is to briefly review the evidence supporting the use of antiemetic agents for the treatment of nausea or vomiting for adults in the ED, and to provide recommendations to help guide therapy. DISCUSSION: The antiemetic agents studied include droperidol, promethazine, prochlorperazine, metoclopramide, and ondansetron. Droperidol was commonly used in the past, and is more effective than prochlorperazine or metoclopramide, but due to the US Food and Drug Administration black box warning regarding the potential for QT prolongation with this drug, its use is limited to refractory cases. Promethazine is more sedating than other comparative agents, and also has the potential for vascular damage upon intravenous administration. It may be a suitable option when sedation is desirable. Patients given prochlorperazine or metoclopramide must be monitored for akathisia that can develop at any time over 48 h post administration. Decreasing the infusion rate can reduce the incidence of this adverse effect, and the effect can be treated with intravenous diphenhydramine. Ondansetron is as effective as promethazine, and is not associated with sedation or akathisia. CONCLUSION: Based on the safety and efficacy of ondansetron, it may be used as a first-line agent for relief of nausea or vomiting for most patient populations in the ED.

Are newer, more expensive pharmacotherapy options associated with superior symptom control compared to less costly agents used in a collaborative practice setting?

Innovative approaches to care may be necessary to provide the most effective symptom management to hospice patients. One approach is prescribing newer pharmacotherapy options with the potential to improve symptom management in hospice. Such therapies are sometimes prescribed outside of Food and Drug Administration indications and are typically more costly than older agents used for the same symptoms. Another approach is the collaborative practice (CP) care model, whereby clinical pharmacists are given prescriptive authority according to evidence-based protocols and algorithms within boundaries approved by a physician. The agents typically included in CP protocols are those with wide therapeutic indices and with substantial evidence to support their use. The purpose of this study was to examine both approaches to management of pain, insomnia, and nausea, comparing symptom scores for those patients who received noncollaborative drug therapies (transdermal fentanyl, zolpidem, and ondansetron) to those who received agents under CP (oral sustained-release opioids, temazepam, and prochlorperazine). The object of the study was to investigate outcomes associated with newer drug therapy options as compared to older agents for the management of pain, insomnia, and nausea. A secondary goal is to compare symptom outcomes for patients receiving pharmaceutical care under CP and non-CP models. The study design was retrospective with a cohort. A total of 50 patients were randomly selected for each cohort of the pain and insomnia study arms. Only 45 patients prescribed oral ondansetron met inclusion criteria for the nausea group; 45 patients prescribed prochlorperazine were randomly selected as the comparator group. Patients were compared on their degree of response to the prescribed therapy. Response was classified as complete, partial, no improvement from baseline, worsened, or unknown. A complete response was defined as the symptom score improving to a 0 of 10, regardless of the previous value documented. A partial response was defined as any improvement in score that did not result in a 0 of 10. No improvement from baseline reflected a lack of overall change in score throughout the series of data points collected. A worsened response was any score found to be higher than the score documented at the time of dispense. The unknown category reflects any set of scores that had an "N/A " documented at the time of medication dispense or when documented for both attempts subsequent to dispensing the medication. A complete response was present in 14 of 50 (28 [corrected] percent) of the patients prescribed oral therapy [corrected] as compared with 12 of 50 (24 [corrected] percent) of those prescribed fentanyl [corrected] (p = .82). Responses defined as partial, no improvement over baseline, worsened, and unknown were also comparable between the two cohorts. A complete response was seen in 26 patients prescribed temazepam (52 percent), whereas only 11 (22 percent) of patients initially prescribed zolpidem achieved the same response (p = .0037). Both groups had a similar distribution of partial, no improvement over baseline, and worsened responses. For the nausea arm of the study, a difference was found in the number of complete responses, favoring prochlorperazine (22 of 45, 48.9 percent for prochlorperazine, 12 of 45, 26.7 percent for ondansetron, p = .0504), as well as an increased number of worse responses seen with ondansetron patients (p = .0513); however, neither difference was statistically significant. Newer pharmacotherapy options for the management of pain, insomnia, and nausea were not found to be superior when compared to older agents prescribed under CP.

Cost-effectiveness analysis of ondansetron and prochlorperazine for the prevention of postoperative nausea and vomiting.

OBJECTIVE: To compare the cost-effectiveness of 2 antiemetic agents, ondansetron and prochlorperazine, for the prevention of postoperative nausea and vomiting (PONV) in patients undergoing total hip replacement or total knee replacement procedures. METHODS: The cost-effectiveness analysis model was applied to data derived from a previous clinical study conducted in 1995 and 1996. This study involved 78 adult patients (62.8% female and 37.2% male) undergoing total hip replacement or total knee replacement procedures. Patients were enrolled in a randomized, double-blind manner to receive either ondansetron 4 mg intrvenously (n=37) or prochlorperazine 10 mg intramuscularly (n=41) immediately upon completion of surgery and were monitored for occurrences of PONV during the subsequent 48 hours. In our analysis, we measured the cost-effectiveness ratio (C/E ratio), defined as the cost per successfully treated patient, for each antiemetic agent using the clinical data obtained from the previous study. RESULTS: The incidence of PONV and use of rescue antiemetics was significantly greater in the ondansetron group compared with the prochlorperazine group. The mean total costs of PONV management per patient in the prochlorperazine and ondansetron groups were dollar 13.99 and dollar 51.98, respectively (based on 2004 average wholesale prices [AWP]). The cost of successfully treating one patient with prochlorperazine and ondansetron was dollar 31.87 and dollar 275.01, respectively. One-way sensitivity analysis was performed adjusting the percent efficacy rate of each antiemetic and the drug cost of ondansetron (up to a 50% reduction in AWP). Prochlorperazine remained the dominant strategy across each scenario. CONCLUSION: The results indicate that prochlorperazine is a more cost-effective antiemetic compared with ondansetron for the prevention of PONV in a mixed gender, adult inpatient population undergoing total joint arthroplasty.

Cost-effectiveness of prophylactic dolasetron or droperidol vs rescue therapy in the prevention of PONV in ambulatory gynecologic surgery.

PURPOSE: To assess the cost-effectiveness of prophylactic therapy (1.25 mg droperidol or 50 mg dolasetron i.v.) vs no prophylaxis (rescue therapy) for the prevention of post-operative nausea and vomiting (PONV) from a Canadian hospital perspective. DESIGN: A predictive decision analytic model using previously published clinical and economic evaluations, and costs of medical care in Canada. SUBJECTS: Ambulatory gynecology surgery patients. INTERVENTIONS: Three strategies administered prior to emergence from anesthesia were compared: 1.25 mg droperidol i.v., 50 mg dolasetron i.v.; and no prophylaxis (rescue therapy). RESULTS: The base case mean cost per patient receiving dolasetron prophylaxis was $28.08 CAN compared with $26.88 CAN per patient receiving droperidol prophylaxis, resulting in a marginal cost of $1.20 CAN. This difference translated in an additional cost of $12.00 CAN for the dolasetron strategy per adverse event avoided over the droperidol strategy. The base case mean cost per patient not receiving prophylaxis was $26.92 resulting in marginal costs of $1.16 CAN and $0.04 CAN when compared to dolasetron and droperidol, respectively. Compared with the no prophylaxis strategy, dolasetron prophylaxis resulted in an incremental cost-effectiveness ratio of $5.82 CAN per additional PONV-free patient. The mean costs incurred per PONV-free patient were calculated to be $48.41 for the dolasetron strategy, $46.34 for the droperidol strategy and $70.83 for the no prophylaxis strategy. CONCLUSIONS: Dolasetron and droperidol given intraoperatively were more cost-effective than no prophylaxis for PONV in patients undergoing ambulatory gynecologic surgery. The difference between the two agents was small and favoured droperidol. The model was robust to plausible changes through sensitivity analyses.

Cost-effectiveness analysis of oral ondansetron and prochlorperazine for preventing nausea and vomiting after moderately emetogenic chemotherapy.

The article reports a study comparing the cost-effectiveness of ondansetron tablets and prochlorperazine capsules in preventing nausea and vomiting after moderately emetogenic chemotherapy in an outpatient setting. A decision analysis model was constructed to compare the cost-effectiveness of the two antiemetics from the perspective of third party health care payers. Probability estimates of the model were derived from a reanalysis of data obtained from a clinical trial directly comparing the two antiemetics. Effectiveness was defined as the number of patients with no emetic episodes and no drug-related adverse events during the 3-day period after receiving chemotherapy. Cost-estimates were based on Average Wholesale Price for medications and national average for hospital services adjusted to 1996 U.S. dollars. Cost-effectiveness ratios for ondansetron and prochlorperazine were $261 and $268 per effectively treated patient, respectively. A series of sensitivity analyses were performed to identify the limits of generalizability of study results. Despite the initial price differential between the two antiemetics, ondansetron was more cost effective than prochlorperazine when the duration of therapy was shorter than 3 days, the total cost of rescue therapy per patient was more than $71, the treatment cost of adverse events was less than $24, the complete relief rate for ondansetron was greater than 58.9 percent, and the complete relief rate for prochlorperazine was less than 26.5 percent.

Efficacy of ondansetron and prochlorperazine for the prevention of postoperative nausea and vomiting after total hip replacement or total knee replacement procedures: a randomized, double-blind, comparative trial.

BACKGROUND: Limited data are available on the efficacy of ondansetron hydrochloride compared with prochlorperazine maleate for the treatment of postoperative nausea and vomiting (PONV). OBJECTIVE: To evaluate the comparative efficacy of ondansetron and prochlorperazine for the prophylaxis of PONV in patients undergoing total hip replacement or total knee replacement procedures. METHODS: A randomized, double-blind, comparative trial was conducted at a tertiary care, university hospital. Seventy-eight patients undergoing elective total hip or total knee replacement procedures received a single dose of ondansetron hydrochloride (n = 37), 4 mg intravenously, or prochlorperazine maleate (n = 41), 10 mg intramuscularly, at the end of the surgical procedure. Rescue therapy was administered every 4 hours as needed during the initial 48 hours. Primary outcome measures were the incidences and severity of PONV. Secondary outcome measures included the number of rescue antiemetic doses required, number of physical therapy cancellations because of PONV, length of hospital stay, and cost of antiemetic agents administered. RESULTS: The incidence of nausea was significantly greater in the ondansetron group compared with the prochlorperazine group (81% vs 56%; odds ratio, 3.4; 95% confidence interval, 1.2-9.4) as was the severity of nausea (P = .04). Multivariate analysis identified administration of ondansetron, history of PONV, obesity, and female sex as risk factors for a nausea event. The incidence of vomiting tended to be greater in the ondansetron group (49% vs 32%; odds ratio, 2.0; 95% confidence interval, 0.8-5.0). The need for rescue antiemetic therapy was also greater in the ondansetron group (46% vs 27%; odds ratio, 2.3; 95% confidence interval, 0.9-6.0). The mean antiemetic drug cost per patient was significantly greater for the ondansetron group ($47.56 vs $2.47; P<.001). However, the proportion of patients who were unable to participate in physical therapy because of PONV and the median length of hospital stay were similar in both groups. CONCLUSION: Prochlorperazine is associated with superior efficacy and significant cost savings compared with ondansetron for the prevention of PONV in patients undergoing total hip and total knee replacement procedures.