Randomized phase II study of TJ-54 (Yokukansan) for postoperative delirium in gastrointestinal and lung malignancy patients

Characteristics associated with effectiveness in postoperative delirium research: a systematic review of randomised controlled trials with meta-regression and meta-analysis

BACKGROUND

Postoperative delirium remains prevalent despite extensive research through randomised trials aimed at reducing its incidence. Understanding trial characteristics associated with interventions' effectiveness facilitates data interpretation.

METHODS

Trial characteristics were extracted from eligible trials identified through two systematic literature searches. Multivariable meta-regression was used to investigate trial characteristics associated with effectiveness estimated using odds ratios. Meta-analysis was used to investigate pooled effectiveness.

RESULTS

We identified 201 eligible trials. Compared with China, trials from the USA/Canada (ratio of odds ratio, 1.89; 95% confidence interval, 1.45-2.45) and Europe/Australia/New Zealand (1.67; 1.29-2.18) had an 89% and 67% higher odds ratio, respectively, suggesting reduced effectiveness. The effectiveness was enhanced when the incidence of postoperative delirium increased (0.85; 0.79-0.92, per 10% increase). Trials with concerns related to deviations from intended interventions reported increased effectiveness compared with those at low risk (0.69; 0.53-0.90). Compared with usual care, certain interventions appeared to have reduced the incidence of postoperative delirium in low-risk trials with low-to-moderate certainty of evidence. However, these findings should be considered inconclusive because of challenges in grouping heterogeneous interventions, the limited number of eligible trials, the prevalence of small-scale studies, and potential publication bias.

CONCLUSIONS

The effectiveness of postoperative delirium trials varied based on the region of trial origin, the incidence of delirium, and the risk of bias. The limitations caution against drawing definitive conclusions from different bodies of evidence. These findings highlight the imperative need to improve the quality of research on a global scale.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42023413984).

Preoperative cognitive function as a risk factor of postoperative delirium in cancer surgeries: A systematic review and meta-analysis

Postoperative delirium (POD) after cancer surgeries can be a result of chemo brain, anesthesia, surgery duration, and preoperative cognitive impairment. Although older age and preoperative cognitive dysfunction were reported to increase the risk of POD in noncardiac surgery, the role of preoperative cognitive function and age in the development of POD after all types of cancer surgeries is not clear. This study aimed to determine the relationship between preoperative cognitive function and likelihood of POD after cancer surgeries. This study used three main online databases and followed PRISMA guidelines. English language original articles that examined preoperative cognitive function before solid tumor cancer surgery and assessed patients for postoperative delirium were included. We employed the random effect meta-analysis method. The overall incidence of POD ranged from 8.7% to 50.9%. The confusion assessment method was the most common tool used to assess delirium. Mini-mental state evaluation (MMSE), Mini-cog, and Montreal cognitive assessment were the most common tools to assess cognitive function. The pooled (total observation = 4676) random effects SMD was estimated at -0.84 (95% confidence interval [CI]: -1.30 to -0.31), indicating that lower MMSE scores before surgery are associated with a higher risk of POD. The pooled (total observation = 2668) random effects OR was estimated at 5.17 (95% CI: 2.51 to -10.63), indicating preoperative cognitive dysfunction can significantly predict the occurrence of POD after cancer surgeries. In conclusion, preoperative cognitive function is an independent and significant predictor of POD after solid tumor cancer surgeries.

A Prospective Randomized Study of the Herbal Medicine Yokukansan for Preventing Delirium After Gastrointestinal Cancer Surgery

Background

Yokukansan, the Chinese Herbal Medicine, may be effective for treating postoperative delirium. However, there is no sufficient evidence supporting this notion. This study aimed to investigate whether yokukansan was effective for preventing delirium after gastrointestinal cancer surgery by the prospective randomized study.

Methods

This was a double-blind, randomized, controlled trial. Patients aged 75 years or older who underwent surgery between May 2017 and December 2019 were randomized to the yokukansan or anchusan (another Herbal Medicine) group. They received treatments with oral intake of assigned medicine from the day before surgery until postoperative day 3. Then, the incidence of postoperative delirium was compared. A psychiatrist diagnosed patients with postoperative delirium.

Results

Seventy-seven patients were enrolled in this study, and the full analysis set comprised 68 patients. In total, 25 of 68 (36.8%) patients presented with postoperative delirium. Specifically, 13 (37.1%) patients in the control group and 12 (36.4%) in the yokukansan group were diagnosed with postoperative delirium. However, the results did not differ significantly in both groups. Moreover, there was no remarkable difference in terms of delirium severity, and adverse events correlated with the medications were not observed.

Conclusion

Yokukansan was ineffective in preventing delirium after gastrointestinal cancer surgery.

Effectiveness and safety of the co-administration of Yokukan-San (Japanese herbal medicine) with antipsychotics in hospitalized older patients with pneumonia

AIM

Behavioral and psychological symptoms and delirium frequently occur in hospitalized older patients with pneumonia and are associated with longer hospital stays. Yokukan-San (YKS, traditional Japanese [Kampo] medicine) and antipsychotics are often used to treat delirium and behavioral and psychological symptoms in Japan. Hence, this study aimed to assess the effectiveness and safety of the co-administration of YKS with atypical antipsychotics in older patients with pneumonia.

METHODS

We used the Japanese Diagnosis Procedure Combination inpatient database to retrospectively identify older patients (≥65 years) hospitalized for pneumonia who received antipsychotics within 3 days of hospitalization. The patients were divided into two groups: those who received atypical antipsychotics alone (control group) and those who received both atypical antipsychotics and YKS (YKS group). We compared length of hospital stay, in-hospital mortality, bone fractures, and administration of potassium products between the two groups using propensity score overlap weighting.

RESULT

We identified 4789 patients in the YKS group and 61 641 in the control group. After propensity score overlap weighting, length of hospital stay was statistically significantly shorter in the YKS group (percentage difference -3.0%; 95% confidence interval -5.8% to -0.3%). The proportion of patients who received potassium products was higher in the YKS group (odds ratio 1.34; 95% confidence interval 1.15-1.55). In-hospital death and bone fractures were not significantly different.

CONCLUSION

Co-administration of YKS with atypical antipsychotics could be a reasonable treatment option for hospitalized older patients with pneumonia and aggressive psychiatric symptoms. Geriatr Gerontol Int 2023; 23: 849-854.

Yokukansan (TJ-54) in patients undergoing surgery: A systematic review and meta-analysis

OBJECTIVES

To evaluate the efficacy and safety of Yokukansan (TJ-54) in patients undergoing surgery.

METHODS

Efficacy was assessed by the onset of delirium, delirium rating scales, anxiety evaluated by Hospital Anxiety and Depression Scale-Anxiety (HADS-A) score, and safety was assessed by any reported adverse events.

RESULTS

Six studies were included. There were no significant differences between the groups in the onset of delirium (risk ratio 1.15, 95% confidence interval [CI] 0.77-1.72), delirium rating scales (early postoperative period: standardized mean difference [SMD] -0.24, 95% CI -1.11 to 0.63; late postoperative period: SMD -0.06, 95% CI -1.56 to 1.45), HADS-A score (mean difference -0.47, 95% CI -1.90 to 0.96), and any adverse events (risk ratio 1.18, 95% CI 0.35-4.00).

CONCLUSIONS

The use of TJ-54 in patients undergoing surgery is not an effective strategy for postoperative delirium and anxiety. Further research considering target patients and durations of administration should be conducted.

Preoperative Risk Factors Associated with Increased Incidence of Postoperative Delirium: Systematic Review of Qualified Clinical Studies

Postoperative delirium (POD) is an acute alteration of mental state, characterized by reduced awareness and attention, occurring up to five postoperative days after recovery from anesthesia. Several original studies and reviews have identified possible perioperative POD risk factors; however, there is no comprehensive review of the preoperative risk factors in patients diagnosed with POD using only validated diagnostic scales. The aim of this systematic review was to report the preoperative risk factors associated with an increased incidence of POD in patients undergoing non-cardiac and non-brain surgery. The reviewed studies included original research papers that used at least one validated diagnostic scale to identify POD occurrence for more than 24 h. A total of 6475 references were retrieved from the database search, with only 260 of them being suitable for further review. Out of the 260 reviewed studies, only 165 that used a validated POD scale reported one or more preoperative risk factors. Forty-one risk factors were identified, with various levels of statistical significance. The extracted risk factors could serve as a preoperative POD risk assessment workup. Future studies dedicated to the further evaluation of the specific preoperative risk factors' contributions to POD could help with the development of a weighted screening tool.

Yokukansan suppresses neuroinflammation in the hippocampus of mice and decreases the duration of lipopolysaccharide- and diazepam-mediated loss of righting reflex induced by pentobarbital

Neuroinflammation is associated with the development of hypoactive delirium, which results in poor clinical outcomes. Drugs effective against hypoactive sur have not yet been established. Yokukansan has an anti-neuroinflammatory effect, making it potentially effective against hypoactive delirium. This study aimed to examine the effect of Yokukansan on the pentobarbital-induced loss of righting reflex duration extended with lipopolysaccharide (LPS)-induced neuroinflammation and diazepam-induced gamma-aminobutyric acid receptor stimulation in a mouse model. The active ingredients in Yokukansan and its anti-neuroinflammatory effect on the hippocampus were also investigated. Furthermore, we examined the in vitro anti-inflammatory effects of Yokukansan on LPS-stimulated BV2 cells, a murine microglial cell line. Findings revealed that treatment with Yokukansan significantly decreased the duration of pentobarbital-induced loss of righting reflex by attenuating the LPS-induced increase in interleukin-6 and tumor necrosis factor-alpha levels in the hippocampus. Moreover, treatment with Yokukansan significantly decreased the number of ionized calcium-binding adapter molecule-1-positive cells in the hippocampal dentate gyrus after 24 h of LPS administration. In addition, glycyrrhizic acid, an active ingredient in Yokukansan, partially decreased the duration of pentobarbital-induced loss of righting reflex. Treatment with Yokukansan also suppressed the expression of inducible nitric oxide, interleukin-6, and tumor necrosis factor mRNA in LPS-stimulated BV2 cells. Thus, these findings suggest that Yokukansan and glycyrrhizic acid may be effective therapeutic agents for treating neuroinflammation-induced hypoactive delirium.

Impact of Gut Microbiota on the Pharmacokinetics of Glycyrrhizic Acid in Yokukansan, a Kampo Medicine

Individual differences in gut microbiota can affect the pharmacokinetics of drugs. Yokukansan is a traditional Japanese kampo medicine used to treat peripheral symptoms of dementia and delirium. A study examining the pharmacokinetics of the components of yokukansan reported large individual differences in the pharmacokinetics of glycyrrhizic acid (GL). It is known that GL is metabolized by intestinal bacteria to glycyrrhetinic acid (GA), which is absorbed in the gastrointestinal tract. Thus, the gut microbiota may affect GL pharmacokinetics. We aimed to clarify the relationship between the gut microbiota composition and pharmacokinetics of GL in yokukansan. Mice were orally administered yokukansan, following the administration of various antibiotics, and the plasma concentration of GA and composition of gut microbiota were measured. The GA plasma concentration was low in mice treated with amoxicillin and vancomycin. The composition of gut microbiota revealed a different pattern from that of the control group. Mice with low plasma levels of GA had lower levels of the phylum Bacteroides and Firmicutes. Additionally, bacteria, such as those belonging to the genera Parabaceroides, Bacteroides, Ruminococcus and an unknown genus in families Lachnospiraceae and Ruminococcaceae, exerted positive correlations between the gene copies and plasma GA levels. These bacteria may contribute to the absorption of GA in the gastrointestinal tract, and multiple bacteria may be involved in GL pharmacokinetics. The pharmacokinetics of GL may be predicted by evaluating the composition of gut bacteria, rather than by evaluating the amount of a single bacterium.

Risk Factors for Pseudoaldosteronism with Yokukansan Use: Analysis Using the Japanese Adverse Drug Report (JADER) Database

Yokukansan is a Kampo formula that is commonly used by the elderly because it is expected to improve peripheral symptoms of dementia and delirium. However, side effects from its use are frequently reported in the elderly. In particular, pseudoaldosteronism caused by the licorice contained in yokukansan leads to hypertension, hypokalemia, and muscle weakness, which may result in death. This study aimed to identify the risk factors of pseudoaldosteronism with yokukansan use. Using cases reported in the Japanese Adverse Drug Report (JADER) database, the reporting odds ratio (ROR) was calculated and compared to assess the risk of pseudoaldosteronism for each licorice-containing Kampo formula. We also analyzed the risk factors for pseudoaldosteronism in patients taking yokukansan. Yokukansan (ROR 2.4, 95% confidence interval (CI) 1.9-2.8; p < 0.001) had a higher risk of pseudoaldosteronism than that of other licorice-containing Kampo formulas. Furthermore, the results of a logistic regression analysis in patients taking yokukansan showed that the licorice dose (OR 1.5, 95% CI 1.2-2.0; p < 0.01), older age (<70 years, OR 5.9, 95% CI 1.8-20; p < 0.01), dementia (OR 2.8, 95% CI 1.6-4.9; p < 0.001), low body weight (<50 kg, OR 2.2, 95% CI 1.1-3.5; p = 0.034) were risk factors for pseudoaldosteronism, Although not significant, treatment with loop diuretics (OR 1.8, 95% CI 0.98-3.5; p = 0.059) tended to increase the risk of pseudoaldosteronism. In summary, patients must understand the risk factors when considering taking yokukansan and reduce the licorice dose they consume.

Where should patients with or at risk of delirium be treated in an acute care system? Comparing the rates of delirium in patients receiving usual care vs alternative care: A systematic review and meta-analysis

BACKGROUND

Delirium is an acute condition that occurs in hospitalised patients and leads to poor patient outcomes that can last long term. Therefore, the importance of prevention is undeniable and adopting new models of care for at-risk patients should be prioritised.

OBJECTIVES

This systematic review and meta-analysis will assess the effectiveness of different interventions designed to prevent or manage delirium in acutely unwell hospitalised patients.

METHODS

MEDLINE, EMBASE, PsycINFO, OpenGrey, Web of Science and reference lists of journals were searched. Eligible studies reported on incidence or duration of delirium, used a validated delirium diagnostic tool and compared an intervention to either a control or another intervention group. Meta-analyses were conducted, and GRADEpro software was used to assess the certainty of evidence. This review is registered on PROSPERO.

RESULTS

A total of 59 studies were included and 33 were eligible for meta-analysis. Delirium incidence was most significantly reduced by non-pharmacological multicomponent interventions compared with usual care, with pooled risk ratios of 0.57 (95% CI: 0.44 to 0.73, 10 randomised controlled trials) and 0.47 (95% CI: 0.35 to 0.64, six observational studies). Single-component interventions did not significantly reduce delirium incidence compared with usual care in seven randomised trials (risk ratio = 0.92, 95% CI: 0.81 to 1.04). The most effective single-component intervention in reducing delirium incidence was a hospital-at-home intervention (risk ratio = 0.29, 95% CI: 0.09 to 0.87).

CONCLUSIONS

Non-pharmacological multicomponent interventions are effective in preventing delirium; however, the same cannot be said for other interventions because of uncertain results. There is some evidence that providing multicomponent interventions in patients' homes is more effective than in a hospital setting. Therefore, researching the benefits of hospital-at-home interventions in delirium prevention is recommended.

Pharmacological strategies to prevent postoperative delirium: a systematic review and network meta-analysis

Background

Postoperative delirium (POD) is a condition of cerebral dysfunction and a common complication after surgery. This study aimed to compare and determine the relative efficacy of pharmacological interventions for preventing POD using a network meta-analysis.

Methods

We performed a systematic and comprehensive search to identify and analyze all randomized controlled trials until June 29, 2020, comparing two or more pharmacological interventions, including placebo, to prevent or reduce POD. The primary outcome was the incidence of POD. We performed a network meta-analysis and used the surface under the cumulative ranking curve (SUCRA) values and rankograms to present the hierarchy of the pharmacological interventions evaluated.

Results

According to the SUCRA value, the incidence of POD decreased in the following order: the combination of propofol and acetaminophen (86.1%), combination of ketamine and dexmedetomidine (86.0%), combination of diazepam, flunitrazepam, and pethidine (84.8%), and olanzapine (75.6%) after all types of anesthesia; combination of propofol and acetaminophen (85.9%), combination of ketamine and dexmedetomidine (83.2%), gabapentin (82.2%), and combination of diazepam, flunitrazepam, and pethidine (79.7%) after general anesthesia; and ketamine (87.1%), combination of propofol and acetaminophen (86.0%), and combination of dexmedetomidine and acetaminophen (66.3%) after cardiac surgery. However, only the dexmedetomidine group showed a lower incidence of POD than the control group after all types of anesthesia and after general anesthesia.

Conclusions

Dexmedetomidine reduced POD compared with the control group. The combination of propofol and acetaminophen and the combination of ketamine and dexmedetomidine seemed to be effective in preventing POD. However, further studies are needed to determine the optimal pharmacological intervention to prevent POD.

Yokukansan for Treatment of Preoperative Anxiety and Prevention of Postoperative Delirium in Cancer Patients Undergoing Highly Invasive Surgery. J-SUPPORT 1605 (ProD Study): A Randomized, Double-Blind, Placebo-Controlled Trial

CONTEXT

No standard preventive or therapeutic methods have been established for preoperative anxiety and postoperative delirium in patients with cancer.

OBJECTIVES

To clarify the therapeutic effect of yokukansan for perioperative psychiatric symptoms in patients with cancer as well as to confirm its safety profile.

METHODS

This is a randomized, double-blind, and placebo-controlled trial conducted at a single center in Tokyo, Japan. About 195 patients with cancer scheduled to undergo tumor resection took one packet of the study drug, which was administered orally. Coprimary outcomes were change in preoperative anxiety assessed with the Hospital Anxiety and Depression Scale-Anxiety and incidence of postoperative delirium assessed with the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Interim analysis was performed with one-third (n = 74) of the target number of registered patients.

RESULTS

Because this trial was canceled based on the results of the interim analysis and the protocol treatment was discontinued in patients who were already registered, conclusions were based on the full analysis set of 160 participants. There were no significant differences between groups in the change of mean Hospital Anxiety and Depression Scale-Anxiety score (intervention group [SD] 0.4 [3.0] vs. placebo group 0.5 [3.0]; P = 0.796) or the incidence of postoperative delirium (32% vs. 30%; P = 0.798). There were no serious adverse events in either group.

CONCLUSION

In patients with cancer undergoing highly invasive surgeries, yokukansan demonstrated no significant efficacy for the treatment of preoperative anxiety or the prevention of postoperative delirium. Yokukansan is already used in daily practice in Japan, but we should be careful with its future use.

American Society for Enhanced Recovery and Perioperative Quality Initiative Joint Consensus Statement on Postoperative Delirium Prevention

Postoperative delirium is a geriatric syndrome that manifests as changes in cognition, attention, and levels of consciousness after surgery. It occurs in up to 50% of patients after major surgery and is associated with adverse outcomes, including increased hospital length of stay, higher cost of care, higher rates of institutionalization after discharge, and higher rates of readmission. Furthermore, it is associated with functional decline and cognitive impairments after surgery. As the age and medical complexity of our surgical population increases, practitioners need the skills to identify and prevent delirium in this high-risk population. Because delirium is a common and consequential postoperative complication, there has been an abundance of recent research focused on delirium, conducted by clinicians from a variety of specialties. There have also been several reviews and recommendation statements; however, these have not been based on robust evidence. The Sixth Perioperative Quality Initiative (POQI-6) consensus conference brought together a team of multidisciplinary experts to formally survey and evaluate the literature on postoperative delirium prevention and provide evidence-based recommendations using an iterative Delphi process and Grading of Recommendations Assessment, Development and Evaluation (GRADE) Criteria for evaluating biomedical literature.

Prevention of postoperative delirium in elderly patients planned for elective surgery: systematic review and meta-analysis

Introduction: Vulnerable or “frail” patients are susceptible to the development of delirium when exposed to triggers such as surgical procedures. Once delirium occurs, interventions have little effect on severity or duration, emphasizing the importance of primary prevention. This review provides an overview of interventions to prevent postoperative delirium in elderly patients undergoing elective surgery.

Methods: A literature search was conducted in March 2018. Randomized controlled trials (RCTs) and before-and-after studies on interventions with potential effects on postoperative delirium in elderly surgical patients were included. Acute admission, planned ICU admission, and cardiac patients were excluded. Full texts were reviewed, and quality was assessed by two independent reviewers. Primary outcome was the incidence of delirium. Secondary outcomes were severity and duration of delirium. Pooled risk ratios (RRs) were calculated for incidences of delirium where similar intervention techniques were used.

Results: Thirty-one RCTs and four before-and-after studies were included for analysis. In 19 studies, intervention decreased the incidences of postoperative delirium. Severity was reduced in three out of nine studies which reported severity of delirium. Duration was reduced in three out of six studies. Pooled analysis showed a significant reduction in delirium incidence for dexmedetomidine treatment, and bispectral index (BIS)-guided anaesthesia. Based on sensitivity analyses, by leaving out studies with a high risk of bias, multicomponent interventions and antipsychotics can also significantly reduce the incidence of delirium.

Conclusion: Multicomponent interventions, the use of antipsychotics, BIS-guidance, and dexmedetomidine treatment can successfully reduce the incidence of postoperative delirium in elderly patients undergoing elective, non-cardiac surgery. However, present studies are heterogeneous, and high-quality studies are scarce. Future studies should add these preventive methods to already existing multimodal and multidisciplinary interventions to tackle as many precipitating factors as possible, starting in the pre-admission period.

Pharmacological Prevention of Postoperative Delirium: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

The high prevalence of delirium among postoperative patients has increased morbidity and mortality. The kind of drug that can effectively reduce the incidence of delirium has become the focus of discussion in recent years. However, a consensus in this respect has yet to be reached.

Methods

Randomized controlled trials (RCTs) were retrieved from the PubMed, Cochrane Library, ClinicalTrials.gov, and Embase databases from their inception through October 12, 2018. We included RCTs of pharmacological prevention for postoperative delirium in adults (at least 18 years), and the Cochrane risk of bias tool was used to evaluate the methodological quality of trials. The primary outcomes were the risk ratios (RRs) of incidence of postoperative delirium, and the secondary outcomes were the RRs of mortality and adverse events in the intervention and control groups.

Results

Thirty-eight trials, which comprised 20302 patients and 18 different drugs, were included in the analysis. Of the 38 studies, 17 were rated as low risk with respect to methodological quality. Dexmedetomidine administration (RR 0.58, 95%CI 0.44-0.76, P<0.01) was associated with a significantly lower incidence of postoperative delirium than the control conditions. However, the findings from the studies with a low risk of bias did not show a significant difference in this beneficial effect (RR 0.64, 95%CI 0.39-1.04, P=0.07). The antipsychotic drugs olanzapine (RR 0.44, 95%CI 0.30- 0.65, P<0.01) and risperidone (RR 0.42, 95%CI 0.19-0.92, P=0.03) had promising effects, but there was a lack of sufficient evidence to obtain a definitive conclusion. The beneficial effect of other drugs, including haloperidol, methylprednisolone, dexamethasone, gabapentin, ketamine, cyproheptadine, donepezil, hypertonic saline, melatonin, nimodipine, ondansetron, pregabalin, rivastigmine, TJ-54, and tryptophan, was not proven on the basis of present evidence.

Conclusion

Among the pharmacological prophylactic measures for postoperative delirium, dexmedetomidine, olanzapine, and risperidone showed higher efficacy than other drugs. However, more high-quality evidence is needed to confirm these results.

Yokukansan for perioperative psychiatric symptoms in cancer patients undergoing high invasive surgery. J-SUPPORT 1605 (ProD Study): study protocol for a randomized controlled trial

Background

Preoperative anxiety and postoperative delirium affect both short- and long-term prognoses in patients with cancer; therefore, these conditions require early prevention and treatment. However, no standard preventive or therapeutic methods have been established for them. Yokukansan, a Japanese herbal medicine for the treatment of insomnia and anxiety, causes relatively few adverse drug reactions and effectively improves the behavioral and psychological symptoms of dementia. Thus, it is expected to be useful for treating and/or preventing perioperative psychiatric symptoms in patients with cancer. The objective of this study is to clarify the therapeutic effect of Yokukansan for preoperative anxiety and its preventive effect on postoperative delirium in cancer patients, as well as to confirm its safety profile.

Methods

This study is a randomized, double-blind, placebo-controlled study in cancer patients scheduled to undergo tumor resection. Patients who provide consent are randomly allocated to receive oral administration of Yokukansan or placebo, and study drug administration is continued for 4 days or longer prior to surgery. We defined two primary endpoints, change in preoperative anxiety and incidence of postoperative delirium. Secondary endpoints are severity score of postoperative delirium, duration of postoperative delirium, amount of benzodiazepines used prior to surgery, amount of antipsychotic agents used after surgery, and number of postoperative hospitalization days. We plan to complete the analysis on March 31, 2021. The target number of registered patients is 110 per group, or 220 in total.

Discussion

This study is the first randomized, double-blind, placebo-controlled study intended to clarify the effects of a Japanese herbal medicine, Yokukansan, in the prevention and treatment of perioperative psychiatric symptoms in patients with cancer. The trial was initiated on August 14, 2017, with 195 subjects randomized by October 5, 2018.

Trial registration

UMIN Clinical Trials Registry (UMIN-CTR), UMIN000027561. Registered on 31 May 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3202-1) contains supplementary material, which is available to authorized users.