著者
西村 富啓 河野 晴一 倉島 篤行 久保 博昭 小池 勇一
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.37, no.6, pp.353-357, 2006-11-30 (Released:2010-06-28)
参考文献数
23
被引用文献数
1 1

Rifampicin (RFP) is one of the first-line drugs in the treatment of tuberculosis. Worldwide, the recommended administration of RFP is before breakfast, however it is commonly administered after the meal in Japan. It is known that the absorption of RFP is affected by a meal. Therefore, the effects of meal on the pharmacokinetics of rifampicin were studied in patients with tuberculosis.Ten male patients participated in this study. Five of the ten patients were given three capsules (450mg of RFP) 30 minutes before breakfast. The other five patients were given the same dose of RFP 30 minutes after breakfast. The mean age and weight were 54.6±3.3 years and 53.9±2.7kg in the group before meal and in the after the meal group, 49.8±8.4 years and 53.8±5.0kg, respectively. All the data were expressed as mean±S.D. Blood samples were taken at 0, 2, 4 and 6 hours after capsule administration. RFP concentra tions in serum were analyzed by reversed-phase high performance liquid chromatography and the relevant pharmacokinetic parameters were calculated. Group means were compared by use of nonparametric statis tics.In the group before meal, the peak concentration (Cmax) was significantly higher than that in the group after meal (9.32±0.88μg/mL versus 5.76 ± 1.04 μg/mL, p<0.05) and the AUC was also significantly higher than that in the group after meal (35.83±3.29μg/hr/mL versus 18.63±4.35μg/hr/mL, p<0.05). These results suggest that RFP should be taken 30 minutes before the meal.
著者
後藤 伸之 白波瀬 正樹 八田 寿夫 政田 幹夫 李 鍾大 坪川 明義 清水 寛正 上田 孝典 中村 徹 北澤 式文
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.27, no.4, pp.725-730, 1996-12-31 (Released:2010-06-28)
参考文献数
7
被引用文献数
2 2

We performed a pharmacoepidemiological study on the effect of different types of questionnaires on coughing and the prevalence of this symptom in out-patients taking angiotensin converting enzyme inhibitors (ACEI) in Fukui Medical School Hospital.The following three types of quentionnaires were prepared:Type 1 ; Questionnaire asking whether the patient has a cough or no after implying that ACEI might cause this symptom.Type 2 ; Questionnaire on the general adverse effects of ACEI, including coughing.Type 3 ; Questionnaire on the general adverse effects of ACEI other than coughing.All questionnaires included a blank space in which the patients were asked to write any adverse effects. The patients were randomly divided into three groups. Each group was given one of the three questionnaires. In the type 3 questionnaire, no patient com-plained of coughing. The prevalence of cough was higher in type 1 questionnaire than in type 2 quetionnaire patients. These results indicate that the prevalence of adverse effects varies greatly depending the type of questions in the questionnaire.
著者
Hiroshi YAMADA Takashi DAIMON Katsuhiko MATSUDA Masayuki YOSHIDA Norikata TAKUMA Yukihiko HARA
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.38, no.5, pp.323-330, 2007-09-30 (Released:2008-10-31)
参考文献数
30
被引用文献数
11 13

Experimental studies have revealed that tea catechins prevent influenza virus infection ; however, the clinical effects have been inconclusive. At the onset of the influenza season, a randomized, double-blind, placebo-controlled study was conducted from December 2005 to March 2006 in Japan. A total of 404 healthy volunteers, 20-65 years of age, were enrolled and randomly assigned to two groups : the catechin group gargling with tea catechin extract solution (approximately 400 μg/mL catechins) or the placebo group gargling without tea catechin extracts. In both groups, gargling was performed three times daily for 90 days. All participants were inoculated with the influenza vaccine before participating in the study. The primary outcome measure was the incidence rate of influenza infection during the study identified by a rapid assay for influenza virus antigens. On an intention to treat basis, 195 participants in the catechin group and 200 in the placebo group who started the intervention were included in the analysis. Of the participants, 6 (1.5%) were infected with influenza. The incidence rate of influenza infection in the catechin group (1.0%, 2 participants) was half that in the control group (2.0%, 4 participants), but not significant between the two groups. We could not find significant effects of gargling with tea catechin on prevention of influenza in the healthy adults inoculated with the influenza vaccine of the 2005-2006 season. However, the effects in more susceptible groups, i.e., those not vaccinated against the influenza virus, children, elderly or immunosuppressed people remain inconclusive.
著者
黒沢 顕三 内田 直樹 岩瀬 万里子 保田 国伸 江花 莉華 平嶋 勇人 石垣 征一郎 松田 和弘 矢野 怜 佐久間 大 安原 一
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.37, no.5, pp.283-290, 2006-09-30 (Released:2010-06-28)
参考文献数
16
被引用文献数
2 3

Drewell ® (diphenhydramine: DPH) is a histamine H1 receptor antagonist and the first OTC sleep aid in Japan. There are few studies which objectively evaluate the sedative effects in elderly subjects. The aim of present study was to evaluate the sedative effects of Drewell ® in healthy elderly and to compare the results with data from young subjects on which we reported previously.A placebo controlled, double-blind, crossover clinical pharmacological study was performed. Eight Japanese healthy elderly male volunteers received 2 tablets of Drewell ®, containing 50mg DPH, or matched placebo orally. Plasma levels of DPH after administration were measured hourly up to 4 hours and every 2 hours up to 8 hours. The sedative effects after the dose were measured by using the saccadic eye movement analyzing system for objective assessment and visual analogue scale (VAS) for subjective assessment.After Drewell ® administration the saccadic peak velocity (SPV) was decreased and saccade inaccuracy (IAC) was increased compared with placebo. There were no significant differences in saccade latency and VAS. The onset of significant decrease of SPV in elderly was delayed compared to young subjects (90 min in elderly vs 30 min in young) although pharmacokinetic parameters were similar in elderly and young subjects. However, the available data of both pharmacokinetic and pharmacodynamic at the same time point until sedation onset was only 60 min. Therefore further investigation is necessary to precisely determine the differences of onset of the sedative effect up to 90 min after Drewell ® administration.
著者
Hayato HIRASHIMA Naoki UCHIDA Ichiro FUKAZAWA Seiichiro ISHIGAKI Eiji UCHIDA Hajime YASUHARA
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.37, no.3, pp.127-133, 2006-05-31 (Released:2010-06-28)
参考文献数
33
被引用文献数
2 2

There are many reports on grapefruit juice (GFJ) increasing the apparent oral bioavailability of several clinically important drugs metabolized by the most abundant isoform of cytochrome P450, i. e. CYP 3A4. Azelnidipine (Calblock ®) is a long-lasting 1, 4-dihydropyridine calcium antagonist currently used in the treatment of hypertension in Japan. In a drug interaction study using human liver microsomes, several CYP3A4 inhibitors and substrates inhibited the oxidative metabolism of azelnidipine to the same extent as nifedipine and felodipine. In order to evaluate the possible interaction of azelnidipine with GFJ in humans, a randomized, two-way crossover study was conducted in eight Japanese healthy volunteers.A single oral dose of 8mg azelnidipine was administered orally with either 250mL water or GFJ after overnight fasting. Blood samples were drawn periodically up to 24hours after dosing. Plasma concentrations of azelnidipine were measured by liquid chromatography-tandem mass spectrometry (LC/APCI-MS/MS).Concomitant administration of azelnidipine with GFJ increased the mean Cmax of azelnidipine by 2.5-fold and the AUC by 3.3-fold compared with water; moreover, the time to reach Cmax (tmax) and the mean residence time (MRT) were slightly delayed. No serious adverse events were observed except one subject described mild symptoms of drug-related headache and flushing accompanied with orthostatic hypotension at 4hrs after administration in the GFJ phase.The results demonstrated the pharmacokinetic interaction between azelnidipine and a single glass of GFJ.
著者
宮原 正 下條 貞友 豊原 敬三 今井 健郎 宮島 真之 本田 英比古 亀谷 雅洋 大関 正弘 小勝 順
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.16, no.2, pp.357-365, 1985-06-30 (Released:2011-02-25)
参考文献数
19
被引用文献数
4 4

A phase I study of EST, a newly synthesized specific thiol protease inhibitor developed as a drug for muscular dystrophy, was performed in healthy adult male volunteers to investigate its safety and pharmacokinetics. EST was administered orally in single doses of 100 mg during fasting, or of 100 mg or 200 mg after a meal. The following results were obtained.The clinical tests and observation of the subjective and objective signs and symptomsfound no change due to EST.EST was detected as E-64-c (effective form of EST) in serum and urine after oral administration. The absorption of EST was slower when administered after a meal than during fasting. The AUC (area under the serum concentration curve) and urinary excretion rate were greater following administration after a meal, which indicates a tendency to better bioavailability of EST.As for the comparison of 100 mg and 200 mg administration after a meal, a distinct dosedependency was observed in the serum concentration and urinary excretion.
著者
河合 昭悦 桑野 友彰 中島 久夫 水野 清史 西本 博之 久保田 信子
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.34, no.4, pp.193-198, 2003-07-31 (Released:2010-06-28)
参考文献数
3

The major factors that have heretofore prevented an efficient implementation of clinical trials include deviations from the protocol at the investigator's site, defectiveness in filling out the case report forms (CRFs), frequent monitoring and fixing work of patient data by the sponsor, handwritten preparation of various documents, and so on.As an experiment in electronic implementation of an efficient clinical trial utilizing information technology, we formed an electronic data capture (EDC) system that efficiently collects clinical data from the investigator's site, and applied it to a clinical trial. As a result, there was no patient with a GCP violation and thus all were eligible as study subjects and the number of correction log form (CLF) for CRFs was considerably reduced. In addition, it was possible to conduct an efficient clinical trial and shorten the study period by utilizing this EDC system. We discuss the future readiness for clinical trials based on this experience of implementation, as well as the challenges that lie ahead.
著者
Tsuyoshi SHIGA Takako KAMIO Kenta UTO Kotaro ARAI
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.52, no.4, pp.101-105, 2021-07-31 (Released:2021-08-18)
参考文献数
18
被引用文献数
1

Trastuzumab, a humanized monoclonal antibody, is used in the treatment of metastatic breast cancer overexpressing human epidermal growth factor receptor 2 (HER2). Trastuzumab-related cardiotoxicity can usually be reversed by interrupting the use of the drug. We present a 78-year-old woman with metastatic HER2-positive breast cancer whose left ventricular ejection fraction (LVEF) decreased from 56% to 37% within 3 months after starting trastuzumab treatment prior to surgery. She complained of shortness of breath on exertion. Trastuzumab was stopped immediately, and an angiotensin-converting enzyme inhibitor and a beta blocker were started. Her LVEF did not increase 6 months after the cessation of trastuzumab use. Low-dose digoxin (0.0625 mg daily) was added, and the patient's LVEF increased from 35% to 44% one month later. The next month, she was able to undergo mastectomy with axillary lymph node dissection followed by radiation and tamoxifen as adjuvant therapy. She was followed up for 3 years after surgery and experienced no recurrence of breast cancer.Trastuzumab-related cardiotoxicity can usually be reversed by interrupting the use of the drug. Patients with inadequate or nonexistent recovery of LVEF despite cardioprotective therapy cannot undergo standard cancer treatment; this restriction leads to a worsened prognosis. Low-dose digoxin in addition to cardioprotective therapy increased our patient's LVEF to over 40%, allowing her to undergo surgery.
著者
熊谷 雄治 藤田 朋恵 横田 愼一 澤田 実花 井澤 志名野 鈴木 勇一 立岡 和弘 庄田 隆 矢後 和夫
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.33, no.5, pp.205-213, 2002-09-30 (Released:2010-06-28)
参考文献数
8

Objectives: Tibolone (KB-889) is a novel compound that possesses tissue-specific hormonal effects. We investigated the pharmacokinetics of tibolone in postmenopausal women in four pharmacokinetic studies, namely a dose linearity study, a multiple dose study, a study in fasted condition, and a study in elderly. In this report, the results obtained from the above four studies are summarized.Methods: In the dose linearity study, a single dose of 0.5 mg, 1 mg and 2 mg of tibolone was administered to 6 postmenopausal women using a 3-period crossover method with at least a 7-day wash-out period between treatments. In the multiple dose study, 2 mg of tibolone was administered once daily for 4 days to 6 postmenopausal women. In the study in fasted condition, a single dose of 2 mg of tibolone was administered to 6 postmenopausal women after overnight fasts. In the study in elderly, a single dose of 2 mg of tibolone was administered to 6 elderly women aged 65 or older. Plasma and urine concentrations of tibolone and its metabolites were measured.Results and Conclusion: Plasma concentrations of the 3α-OH and 3β-OH metabolites of tibolone were measured, since the levels of tibolone and its Δ4-isomer were under or near the detection limits. After single dose administration of 0.5, 1 and 2 mg of tibolone, the means of Cmax and AUC0-12h of plasma 3α-OH metabolite were 2.3, 3.5 and 6.5 ng/mL and 10.2, 18.5 and 36.7 ng·Eh/mL, respectively, and those of 3β-OH metabolites were 0.9, 1.7 and 3.1 ng/mL and 4.6, 8.8 and 17.7 ng·Eh/mL, respectively. The means of Tmax and T1/2 (6-12h) of plasma 3α-OH and 3β-OH metabolites were between 3.7 and 5.7 h, and between 3.2 and 4.4 h, respectively. The pharmacokinetic properties of tibolone were considered to be linear within the dose range of 0.5 mg to 2 mg. In the multiple dose study, no accumulation was found. When comparing the pharmacokinetic parameters obtained from the study in fasted condition with those of day 1 of the multiple dose study, the absorption of tibolone was rapid under fasted condition, but AUC was not influenced by food intake. [The means of Tmax of 3α-OH and 3β-OH metabolites were 1.17 and 1.33 h in fasted condition, and 3.83 and 4.00 h on day 1 of multiple dose.] Finally no difference in pharmacokinetics was found between postmenopausal women and elderly women in the comparison of the pharmacokinetic parameters obtained from the study in the elderly and those of day 1 of the multiple dose study.
著者
中園 直子 猪爪 信夫 飛野 幸子 岩奥 玲子 中野 眞汎
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.16, no.2, pp.401-407, 1985-06-30 (Released:2010-06-28)
参考文献数
27
被引用文献数
1

The bioavailability of theophylline following administration of two pediatric sustained release tablets (Theona-P® and Theo-Dur®), two crushed sustained release tablets (crushed Theona-P® and crushed Theo-Dur®), and newly developed sustained release granules (E-0686-023, investigational drug) was studied in four volunteers by measuring salivary concentrations. The pharmacokinetic parameters tmax and MRT (mean residence time) for crushed Theona-P® and crushed Theo-Dur® were significantly shorter compared to Theona-P®, Theo-Dur®, and E-0686 granules, but the AUC0-∞ values were not different among them. The results show that each preparation is equivalent in the extent of bioavailability but not in the rate of bioavailability. More frequent administration is required when crushed Theona-P® or crushed Theo-Dur® are taken, and sustained release granules are desirable in children with chronic asthma who cannot swallow tablets.
著者
中野 重行 菅原 英世 坂本 真佐哉 小関 哲郎 上村 尚人 丹生 聖治 角南 由紀子 松木 俊二 梅月 恵美
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.30, no.1, pp.1-7, 1999-01-31 (Released:2010-06-28)
参考文献数
8
被引用文献数
5 5

Objectives: A variety of factors influence the incidence of placebo effects . The purpose of this study was to clarify the influence of factors such as the doctor-patient relationship, patient's motivation and expectation for drug therapy on placebo effectsMethods: Data were obtained from two double-blind randomized clinical trials with a placebo control group of 123 patients with psychosomatic disorders. The improvement was assessed by doctors at two weeks after the initiation of treatment. The doctor-patient relationship, patient's motivation and expectation for drug therapy were assessed by doctors at the beginning of clinical trials.Results: The improvement rate in the placebo group was 42.3%, whereas the improvement rate in the diazepam group was 57.6% (p <0.05). In the placebo group, improvement rates were 50.0% in patients with a good doctor-patient relationship, 31.4% in patients with a moderate relationship and 10.0% in patients with a poor relationship (p < 0.05).Improvement rates were 46.1% in patients with a good motiva-tion for drug therapy and 19.0% in patients with poor or lack of motivation (p <0.01).Improvement rates were 36.4% in patients with low expectation for drug therapy, 53.0% in patients with a moderate one, and 7.7% in patients with high expectation (p <0.05).Conclusion: In patients with psychosomatic disorders, factors such as the doctor-patient relationship, patient's motivation and expectation for drug therapy clearly influ-ence the incidence of placebo effects.
著者
Iori SAKAKIBARA Kazuki IDE Yohei KAWASAKI
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.48, no.3, pp.95-98, 2017-05-31 (Released:2017-06-21)
参考文献数
10

The National Center Biobank Network (NCBN) was launched in Japan in 2012 and currently comprises the biobanks of six national centers. The NCBN collects and controls information of patients' biological specimens along with a supplemental catalog of disease names, medical examinatian forms, and diagnostic information. However, these data do not comply with universal standard data formats. In this study, we investigated the possibility of data sharing or collaboration between the NCBN and other biobanks, and whether the data collected and controlled at the NCBN can be standardized following the international standard guidelines of the Clinical Data Interchange Standards Consortium (CDISC) to allow use of these data in future clinical studies. We also evaluated whether data mapped to the Study Data Tabulation Model (SDTM), a standard specification regulated under the CDISC, can be converted to Analysis Data Models (ADaMs) to facilitate searches for the feasibility of data adaptation to clinical trials, and determined the advantages and drawbacks of this conversion. In addition, we examined the potential of utilizing standardized data sets in clinical trials. As a result, we classified the 202 NCBN catalog data items into seven SDTM domains, which were subsequently converted into four ADaM domains. While we expect that conversion of NCBN catalog data to ADaM is possible, the NCBN catalog data currently lack items that can be utilized in actual clinical trials. Thus it is necessary to retain the medical data required for clinical trials at each national center. Standardization of these data is essential, but is currently difficult given the lack of standard clinical trial protocols. Thus, standardization of the data at national center would help promote their usage for planning clinical trials.
著者
鈴木 徳治 藤田 正一 古座谷 醇 大木 俊光
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.14, no.3, pp.437-452, 1983-09-30 (Released:2010-06-28)
参考文献数
39

The usefulness of an approximation formula to calculate the power of analysis of variance for bioequivalence tests in a two-way crossover design was examined by comparison with the power estimated from the upper probability integrals of the noncentral F-distribution. The approximation formula was shown to be useful for the calculation of the power for usual bioequivalence tests . The calculation of the power for bioequivalence tests in a multi-way crossover design was attempted using the approximation formula.Further, data in previously published reports on bioequivalence between drug preparations were reviewed from the standpoint of the power. Only 24 of 86 bioequivalence analyses conducted with 25 different drugs gave a power higher than 80% to detect a 20% difference in bioavailability with α=0.05, and the power of about a half of the analyses was lower than 50%.
著者
井藤 達也 高岡 和夫 竹本 功 秦 温信 井上 勝一 佐々木 健太郎 平野 剛 井関 健 菅原 満 宮崎 勝巳
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.33, no.2, pp.47-52, 2002-03-31 (Released:2010-06-28)
参考文献数
13

The purpose of this study was to evaluate the distribution of CPT-11 and its active metabolite, SN-38, in pleural and pericardial fluid after intravenous administration.Two patients with lung cancer were treated with intravenous CPT-11 (60 mg/m2) on days 1, 8, and 15. The CPT-11 was detected in the pleural fluid 1.5 hr after the begining of intravenous infusion, and the level reached the maximum 24 hrs later. Similarly, the active metabolite SN-38 was detected in the pleural fluid 1.5 hr after the begining of intravenous infusion, and SN-38 concentration in the pleural fluid was almost as high as that in plasma 24 hrs later. These results suggest that intravenously administered CPT-11 may penetrate the thoracic cavity and may be metabolized to SN-38 there. The proportions of maximum concentrations of CPT-11 and SN-38 in the pleural fluid to the corresponding plasma levels were 20.4% and 28.5%, respectively. In addition, the AUCs of the lactone form SN-38 were much lower than those of the carboxyl form in the pleural fluid.CPT-11, SN-38 and SN-38 glucronide showed similar pharmacokinetics in the pericardium as that in plasma.
著者
景山 孝正 大野 文俊 安田 行寛 新藤 恭司 三谷 鳴夫 丸伝 章 赤沢 明
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.10, no.4, pp.525-533, 1979-12-30 (Released:2010-06-28)
参考文献数
9
被引用文献数
1 1

The biological fate of suxibuzone (SB), a new non-steroidal anti-inflammatory agent, was studied in healthy male volunteers with single oral doses and compared with that of phenylbutazone (PB) by a cross-over test, with the following results:1) PB, oxyphenbutazone (Oxy-PB), and γ-hydroxy-phenylbutazone (γ-Hydroxy-PB) were identified in plasma after oral administration of SB. Moreover these metabolites, their glucuronides, SB-glucuronide, 4-hydroxymethyl-phenylbutazone (4-HM-PB)-glucuronide, and p, γ-dihydroxy-phenylbutazone (p, γ-DH-PB) were found in urine.2) Peak plasma concentration of the metabolites was obtained 4 hrs after a single oral dose of 426 mg of SB when the concentration of PB, the main metaboliteof SB, was 36μg/ml, much the same as the corresponding level in the volunteers receiving PB. On the other hand, there was no difference between volunteers receiving SB and PB interms of the concentration of Oxy-PB. But the concentration of γ-Hydroxy-PB was higher after oral SB than after oral PB.3) Urinary excretion of the metabolites was about 8% of the administered dose up to 16 8hrs after oral doses of SB or PB, but in the period shortly after oral doses of SB, Oxy-PB-glucuronide and γ-Hydroxy-PB were excreted to ag reater extent than after oral doses of PB.4) From these results in the plasma and urine after oral doses of SB, it was found that SB may be characterized as a prodrug of PB.5) During the experiment, no side effects or abnormalities were observed in the medical examination and laboratory test except for a slight decrease in the uric acid level in plasma.
著者
HASHIGUCHI Masayuki WATANABE Eriko CHIYODA Takeshi IRIE Shin KUROKAWA Tatsuo MOCHIZUKI Mayumi
出版者
The Japanese Society of Clinical Pharmacology and Therapeutics
雑誌
臨床薬理 (ISSN:03881601)
巻号頁・発行日
vol.44, no.1, pp.29-36, 2013
被引用文献数
1

<b>Background:</b> Lifestyle-related diseases are increasing in Japan, and the national medical expenditure is increasing. Converting prescription drugs to over-the-ounter (OTC) drugs would appear to be one solution to cut expenditure. The willingness to pay (WTP) of the Japanese public for OTC imidapril, an angiotensin-converting enzyme (ACE) inhibitor, as a healthcare-related item has not been evaluated.<br><b>Objective:</b> To measure the value of OTC imidapril as a health care-related item by investigating the public's WTP as self-medication for primary prevention of stroke, assuming that ACE inhibitors are switched from prescription-only to OTC status.<br><b>Methods:</b> A questionnaire was distributed among healthy individuals engaged in various jobs in office buildings (including a clinic) in Tokyo and Fukuoka, Japan. For the WTP question format, the double-bound dichotomous choice approach was employed. Participants were randomly assigned to 3 groups. Group A was provided with a starting price per month of ¥6,000, group B with ¥8,000, and group C with ¥10,000. Weibull regression analysis was used to investigate factors affecting WTP.<br><b>Results:</b> The questionnaire survey was completed correctly by 311 individuals (156 men, mean age 50 years), and the mean WTP was ¥7,237 per month. Weibull regression analysis showed that gender significantly affected WTP. The bid acceptance rates differed among the age groups of 20-39 years, 40-64 years, and ≥65 years.<br><b>Conclusion:</b> The public's WTP amount was approximately ¥7,000 per month, and the WTP based on the questionnaire responses was about 20% lower than the present cost for physician visits. (Jpn J Clin Pharmacol Ther 2013; 44(1): 29-36)