Pharmaceutical studies of levothyroxine sodium hydrate suppository provided as a hospital preparation.

The levothyroxine sodium hydrate suppository (L-T4-suppository) is provided as a hospital preparation for the treatment of hypothyroid patients with dysphagia in Japan because only oral preparations of levothyroxine sodium (L-T4) are approved for the treatment of hypothyroidism. However, it has been found that serum thyroxine and triiodothyronine levels do not increase as expected with the hospital preparation, requiring a higher dosage of L-T4 in the L-T4-suppository than in the oral preparations. In this study, to determine an effective thyroid gland hormone-replacement therapy for patients with dysphagia, the pharmaceutical properties of the L-T4-suppository were investigated. Suppositories containing 300 µg L-T4 in a base of Witepsol H-15 and Witepsol E-75 (ratio of 1 : 1) were prepared according to Chiba University Hospital's protocol. Content uniformity, stability, and suppository release were tested. The L-T4-suppository had uniform weight and content. The content and release property were stable over 90 d when the L-T4-suppository was stored at 4 °C and protected from light. The release rate of L-T4 increased as pH increased. However, no L-T4 was released below pH 7.2. The release rate of L-T4 decreased as temperature decreased. These findings suggest that the low level of release of L-T4 in the rectum under physiological conditions may be the cause of the low serum thyroxine and triiodothyronine levels following L-T4-suppository administration.

Super-acute onset of tumor lysis syndrome accompanied by hypercytokinemia during treatment of Hodgkin's lymphoma with ABVD chemotherapy.

BACKGROUND: Tumor lysis syndrome (TLS) is a group of life-threatening metabolic complications that can occur after initiation of cancer chemotherapy. Onset of TLS in the middle of chemotherapy, however, has not been reported previously in patients with hematologic malignancies. OBJECTIVE: We report a case of a patient who experienced TLS of super-acute onset accompanied by hypercytokinemia during chemotherapy treatment with a combination of doxorubicin (Adriamycin), bleomycin, vinblastine, and dacarbazine (ABVD). CASE SUMMARY: A 36-year-old Japanese man (height, 182 cm; weight, 83 kg; body surface area, 2.04 m(2)) was admitted to the hospital for the treatment of malignant lymphoma (clinical stage IVB Hodgkin's lymphoma). Chemotherapy was initiated using the ABVD regimen (doxorubicin [Adriamycin] 25 mg/m(2) by 30-minute infusion, bleomycin 9 mg/m(2) by 30-minute infusion, vinblastine 6 mg/m(2) by bolus injection, and dacarbazine 375 mg/m(2) by 2-hour infusion). During the dacarbazine infusion, the patient's body temperature rose from 36.5 degrees C to 42 degrees C; he experienced a convulsion and then lost consciousness. The convulsion was not suppressed despite the use of diazepam (5 mg IV twice) and phenytoin (500 mg IV). The patient was then transferred to the intensive care unit and sedated using a continuous infusion of midazolam (10 mg/h). Levels of serum lactate dehydrogenase, aspartate aminotransferase, uric acid, blood urea nitrogen, and creatinine evaluated shortly after the ABVD regimen were outside normal limits. In addition, interleukin-6 (IL-6) concentrations were elevated to 54,220 pg/mL. Continuous hemodiafiltration was immediately performed to lower the elevated levels of IL-6. The next day, IL-6 concentrations decreased to 97 pg/mL, and the patient was weaned from ventilator support and sedation. The patient had no adverse effects after the event. According to the results of an assessment using the Naranjo adverse drug reaction probability scale (score = 3), the development of TLS in this patient was possibly related to the chemotherapy regimen. CONCLUSIONS: ABVD chemotherapy was possibly associated with the super-acute onset of TLS in this patient. In addition, hypercytokinemia occurred with TLS, which led to pyrexia, convulsion, and loss of consciousness.

Probable interaction between warfarin and antitumor agents used in R-ESHAP chemotherapy.

BACKGROUND: The pharmacologic effects of warfarin might be altered by various factors, including drug-drug interaction. CASE SUMMARY: A 49-year-old Japanese man (height, 174 cm; weight, 68 kg) presented with a 20-month history of malignant lymphoma (diffuse large B cell lymphoma, clinical stage IV). He was treated with a combination of rituximab chemotherapy and etoposide, cisplatin, high-dose cytarabine, and methyl-prednisolone (R-ESHAP). He had been receiving warfarin for the secondary prevention of pulmonary embolism with deep venous thrombosis. When R-ESHAP was started, international normalized ratio (INR) increased from 1 to 5. This phenomenon was observed again in the second R-ESHAP. The INR was increased from 2.44 to 4.71 during chemotherapy but was returned to within the normal range (1.05; normal range: 0.81-1.009) 5 days after chemotherapy was completed. CONCLUSION: In this patient, R-ESHAP chemotherapy might have affected warfarin anticoagulation sensitivity; thus, careful monitoring of INR is essential, particularly in patients receiving warfarin who undergo R-ESHAP chemotherapy.

[Appropriate use of anti-methicillin-resistant Staphylococcus aureus agents in a retrospective study].

The track records of the use of anti-methicillin-resistant Staphylococcus aureus agents (anti-MRSA agents) in a 5-year period (2001.4-2006.3) were collected, and cases in which anti-MRSA agents were used for >4 days were selected. In each case, the results of laboratory data and bacterial examination before and after administering the anti-MRSA agents were investigated retrospectively. In addition, it was also investigated in each case whether therapeutic drug monitoring (TDM) was carried out. It was observed that the number of patients treated with anti-MRSA agents and the total dose of anti-MRSA agents used tended to increase over time, except for arbekacin sulfate. It was, however, shown that treatment with anti-MRSA agents resulted in significant decreases in body temperature, C-reactive protein, and white blood cell counts. Bacterial examination was conducted in 75.6% of the patients treated with anti-MRSA agents, with MRSA being detected in 72.4% of the cases examined. On the other hand, TDM was also conducted in 60% of the cases, but this was at a lower percentage than that of the other examinations. Quantitative bacterial examination after treatment with anti-MRSA agents indicates that TDM can be considered important for the appropriate use of anti-MRSA agents.

Identification and partial characterization of a novel CYP2C9 splicing variant encoding a protein lacking eight amino acid residues.

CYP2C9 is known as an enzyme responsible for the metabolism of various clinically important drugs. Recently, we cloned a cDNA corresponding to a CYP2C9 splicing variant (SV), which seemed to have an open reading frame of a protein with 482 amino acid residues. To investigate whether or not the SV can be translated as a functionally active protein, we expressed the CYP2C9SV in insect cells, and spectrophotometric and enzymatic properties were characterized. The CYP2C9SV protein showed a typical reduced CO-difference spectrum, indicating that the translated protein binds a heme moiety. However, CYP2C9SV did not metabolize tolbutamide or diclofenac at all, suggesting that the SV protein appeared to lack the ability to catalyze reactions mediated by CYP2C9. Although the CYP2C9SV mRNA was detected in all human liver samples examined in this study by real-time PCR, the level was generally low, ranging between 0.7 and 9.6% of the normal CYP2C9 mRNA. These results suggest that the CYP2C9SV protein is unlikely to contribute to CYP2C9 activities, although it appears to be expressed in most individuals.

Phase I/II adenoviral p53 gene therapy for chemoradiation resistant advanced esophageal squamous cell carcinoma.

We investigated the feasibility, safety, biological activity and therapeutic efficacy of adenovirus-mediated p53 gene transfer in patients with chemoradiation resistant advanced esophageal carcinoma. Eligible patients were not surgical candidates and had measurable, advanced squamous cell carcinoma of the esophagus that was resistant to chemoradiation therapy. On a 28-day cycle, intratumoral injections of Ad5CMV-p53 (INGN 201; ADVEXIN) were administered on days 1 and 3 at four dose levels (10 x 10(11) particles to 25 x 10(11) particles) and treated for up to five cycles. Ten patients received a total of 26 cycles with no dose-limiting toxicity. Administration of multiple courses was feasible and well-tolerated. Local tumor responses revealed stable disease in nine cases and progressive disease in one case. The overall responses were stable in six and progressive in four cases. Using polymerase chain reaction (PCR) analyses, gene transfer and p53 specific transgene expression were detected in tumor biopsy tissue from all patients. mRNA levels of p53, p21 and MDM2 increased in all but one case. Three patients showed absence of disease upon repeat biopsies. Substantial improvement in swallowing was observed in one patient with stenotic lesions. Intratumoral injection of Ad5CMV-p53 is safe, feasible and biologically active when administered in multiple doses to patients with esophageal cancer. Observations from this study indicate that this treatment results in local antitumor effects in chemoradiation resistant esophageal squamous cell carcinoma.

Effects of continuous ingestion of green tea or grape seed extracts on the pharmacokinetics of midazolam.

Limited systematic data on herb-drug interaction are available, despite many opportunities to concomitant use of herb with prescribed drugs. We investigated the effects of 15 herbal extracts in dietary supplements on CYP2C9, CYP2D6 and CYP3A4 activities in human liver microsomes. Strong inhibition of these CYP activities was found by the addition of green tea extracts (GTE) or grape seed extracts (GSE) in vitro. To examine the effects of these extracts on CYP3A activities in vivo, the pharmacokinetics of midazolam (MDZ) was analyzed in rats. Although single treatments with these extracts had negligible effects, 1 week of treatment with them resulted in a significant increase in the ke of intravenously administered MDZ, indicating the induction of CYP3A in the liver. In contrast, 1 week of treatment with GTE, but not GSE, caused a significant increase in the C(max) and AUC(0-infinity) of orally administered MDZ without change in the t(1/2), suggesting a reduction in CYP3A activity in the small intestines. These studies indicate that subchronic ingestion of GTE or GSE may alter the pharmacokinetics of MDZ, and the effects of GTE on CYP3A activity appear opposite between liver and small intestine, which could not be predicted from in vitro experiments.

[The interchange between hospital pharmacists and pharmacists: evaluation of practical classes "chozaigijutsu-konwakai" from the participants].

We have held practical classes called chozaigijutsu-konwakai(Konwakai) for pharmacists working in drugstores every month since December 1994. Konwakai is composed of lectures and practice. The practice is carried out for pharmacists to obtain a better understanding of prescriptions and compounding them in exercises. In this study, we analyzed the answers to questionnaires distributed at the end of each konwakai to all participants. It was found that the age of participants as well as the length of compounding experience varied markedly, indicating that pharmacists of various generations are interested in konwakai. Regarding the contents of lectures and practice, the answers indicated that the practice was particularly useful, suggesting the importance of exercise for learning techniques in compounding. Since there were many requests for consultations on routine work, frequent communications between pharmacists in the hospital and drugstores appears necessary. In conclusion, regular meetings including practical classes such as konwakai are very important for pharmacists in drugstores that receive prescriptions from hospitals. Further efforts to improve the konwakai should be maid in the future.

CYP3A4 and CYP3A7-mediated carbamazepine 10,11-epoxidation are activated by differential endogenous steroids.

Recently, we reported that several endogenous steroids affect CYP3A4-mediated drug metabolism, using human adult liver microsomes as an enzyme source. Especially, carbamazepine (CBZ) 10,11-epoxidation is activated by androstenedione (AND). In the present studies, we investigated the effects of endogenous steroids on the activity of CBZ 10,11-epoxidation by expressed CYP3A4 and CYP3A7. When expressed CYP3A4 was used as an enzyme source, the addition of AND to the reaction mixture also caused a drastic increase in the activity of CBZ 10,11-epoxidase, and resulted in a change in the kinetics from sigmoid to Michaelis-Menten type. On the other hand, expressed CYP3A7-mediated CBZ 10,11-epoxidation was activated by sulfate conjugate steroids, such as pregnenolone 3-sulfate, 17alpha-hydroxypregnenolone 3-sulfate, and dehydroepiandrosterone 3-sulfate (DHEA-S), whereas the unconjugated form corresponding to these three steroids did not activate the reaction. Especially, DHEA-S was found to be a potent activator of CBZ 10,11-epoxidation by expressed CYP3A7. The kinetic character of CBZ 10,11-epoxidation by CYP3A7 is Michaelis-Menten type regardless of the presence of DHEA-S. The presence of DHEA-S caused a decrease in K(m) and increase in V(max) for CYP3A7-mediated CBZ 10,11-epoxidation, whereas DHEA-S 16alpha-hydroxylation was not affected by the coexistence of CBZ. In conclusion, CYP3A4 and CYP3A7-mediated CBZ 10,11-epoxidations are activated by different types of endogenous steroids. This is the first report regarding CYP3A7 cooperativity.

Effects of Kampo extracts on drug metabolism in rat liver microsomes: Rhei Rhizoma extract and Glycyrrhizae Radix extract inhibit drug oxidation.

In the present study, the effects on drug oxidations in rat liver microsomes in vitro using 126 Kampo extracts were investigated. Although the effects of inhibition on drug oxidations were dependent on the Kampo extracts and probe reactions studied, most of the Kampo extracts showed inhibitory effects on both N-demethylations of aminopyrine and erythromycin in rat liver microsomes. Among the Kampo extracts studied herein, Daio-kanzo-to exhibited the most remarkable inhibitory effect on both reactions. The Rhei Rhizoma extract inhibited not only aminopyrine and erythromycin N-demethylations, but also phenacetin O-deethylation, 7-ethoxycoumarin O-deethylation, ethanol oxidation and tolbutamide 4-hydroxylation in rat liver microsomes. The Glycyrrhizae Radix extract also showed a remarkable inhibitory effect on phenacetin O-deethylation as well as aminopyrine and erythromycin N-demethylations. In contrast, the Glycyrrhizae Radix extract virtually showed no effect on ethanol oxidation.

Effects of endogenous steroids on CYP3A4-mediated drug metabolism by human liver microsomes.

In the present study, we investigated the effects of 14 endogenous steroids on the CYP3A4-mediated drug metabolism by human liver microsomes in vitro. Nevirapine (NVP) 2-, 12-hydroxylations, carbamazepine (CBZ) 10,11-epoxidation, triazolam (TZM) 1'-, 4-hydroxylations, erythromycin (EM) N-demethylation, and 2-sulphamoylacetylphenol (SMAP) formation from zonisamide (ZNS) were investigated. The activities of the NVP 2-, 12-hydroxylations, the CBZ 10,11-epoxidation, and the TZM 4-hydroxylation were activated by endogenous androgens, such as androstenedione (AND), testosterone, and dehydroepiandrosterone. However, these androgens inhibited EM N-demethylation, TZM 1'-hydroxylation, and SMAP formation. To understand the mechanisms of these effects of androgens on CYP3A4 activities, we performed a kinetic analysis of the metabolism of CBZ and ZNS in the presence or absence of AND using the modified two-site equation model. The addition of AND to the reaction mixture caused a drastic increase in the activity of CBZ 10,11-epoxidase, especially at a low substrate concentration, and resulted in a change in the kinetics from the sigmoid to Michaelis-Menten type. On the other hand, the metabolism of ZNS was strongly inhibited by AND, although no allosteric change was observed in this case. These data demonstrate that endogenous steroids, especially androgens, strongly affect CYP3A4-mediated drug metabolism in vitro. The postulated mechanisms of the interactions between AND and CBZ or ZNS are discussed.

Molecular cloning of monkey CYP2C43 cDNA and expression in yeast.

A cDNA clone designated as CYP2C43 was isolated from the rhesus monkey liver cDNA library. The first 16 amino acid residues at the N-terminal region of this cDNA product were identical with those of P450 CMLd which have been purified and characterized as S-mephenytoin 4'-hydroxylase in monkey liver. The respective nucleotide and deduced amino acid sequences of CYP2C43 were 83% and 77%, identical to those of monkey CYP2C20. Antibody against CYP2C9 detected a protein in the microsomes of yeast transformed CYP2C43 expression plasmid. The specific content of recombinant CYP2C43 was 78.0 pmol/mg protein and the yield was 4.23 nmol/l of the culture. CYP2C43 was able to metabolize S-mephenytoin stereo-selectively. The activity for S-mephenytoin in the microsomes reconstituted with or without cytochrome b(5) was found to be 96.2 or 23.7 pmol/min/nmol P450, respectively. CYP2C43, however, did not show any oxidative activity for tolbutamide. These results indicate that CYP2C43 is the second identified member of the monkey CYP2C subfamily and a cDNA clone encoding P450 CMLd in monkey.