Combined Use of Calcium-channel Blockers With Ombitasvir/Paritaprevir/Ritonavir Exacerbates Peripheral Edema in Elderly Japanese Patients.

BACKGROUND/AIM: The antiviral agent ritonavir is a substrate for cytochrome P450 3A4 (CYP3A4); therefore, concomitant use of CYP3A4-metabolising drugs might cause adverse reactions to this drug. We investigated the plasma level of calcium channel blockers (CCBs) as CYP3A4 substrates and peripheral edema as a potential adverse drug reaction possibly caused by the anti-hepatitis C virus (HCV) regimen of ombitasvir/paritaprevir/ritonavir (OPR) and CCBs. PATIENTS AND METHODS: We enrolled Japanese patients prescribed OPR for HCV infection. Peripheral edema was graded according to the Common Terminology Criteria for Adverse Events ver. 4. Plasma samples were collected on days 0, 7, 14, 28, and 42 after antiviral treatment, at the trough level. RESULTS: Out of 52 patients, 64% experienced grade 1 or grade 2 peripheral edema, but not grade 3. Concomitant use of CCBs significantly increased the emergence of grade 2 edema (62%), compared with patients treated solely with OPR (48%). The use of OPR significantly increased the plasma concentration of amlodipine. CONCLUSION: Peripheral edema in patients treated with OPR and CCBs, although tolerable, should be closely monitored.

Evaluation of the effectiveness of caspofungin against febrile neutropenia and the factors related to the alteration in its plasma concentration.

Caspofungin (CPFG) is an echinocandin antifungal agent that inhibits the synthesis of ß-1, 3-D-glucan, a critical component of the cell wall of target fungi. Several clinical studies have confirmed the efficacy and safety of CPFG in patients with febrile neutropenia (FN); however, there are no reports available in Japanese patients with FN. Therefore, we investigated the therapeutic efficacy and pharmacokinetics of CPFG as an empirical therapy in a Japanese hospital. Twenty-four Japanese patients, who were diagnosed with FN at Gifu University Hospital from February 2014 to August 2017, were enrolled. Blood samples were collected at the end of CPFG dosing (0.5 h after the infusion) on day 1 and immediately prior to the next infusion on days 2, 3, and 4. The concentration of CPFG in plasma was measured by high-performance liquid chromatography. The efficacy was assessed by five of the component endpoints, and safety was monitored according to the Common Terminology Criteria for Adverse Events. CPFG showed an excellent effect against FN (75%, 18/24), without any serious hepatic or renal toxicity. Regarding the pharmacokinetics, the plasma concentration of CPFG was significantly correlated with body weight; although, no correlation was observed between the plasma concentration of CPFG and the other factors investigated, such as gender or laboratory results. These results suggest the high efficacy, safety, and tolerability of CPFG as an empirical antifungal therapy for Japanese patients with FN.

ß-Amyrin Biosynthesis: The Methyl-30 Group of (3S)-2,3-Oxidosqualene Is More Critical to Its Correct Folding To Generate the Pentacyclic Scaffold than the Methyl-24 Group.

Oxidosqualene cyclases catalyze the transformation of oxidosqualene (1) into numerous cyclic triterpenes. Enzymatic reactions of 24-noroxidosqualene (8) and 30-noroxidosqualene (9) with Euphorbia tirucalli ß-amyrin synthase were conducted to examine the role of the branched methyl groups of compound 1 in the ß-amyrin biosynthesis. Substrate 8 almost exclusively afforded 30-nor-ß-amyrin (>95.5 %), which was produced through a normal cyclization pathway, along with minor products (<4.5 %). However, a lack of the Me-30 group (analogue 9) resulted in significantly high production of premature cyclization products, including 6/6/6/5-fused tetracyclic and 6/6/6/6/5-fused pentacyclic skeletons (64.6 %). In addition, the fully cyclized product (35.4 %) having the 6/6/6/6/6-fused pentacycle was produced; however, the normally cyclized product, 29-nor-ß-amyrin was present in only 18.6 % of these products. The conversion yield of substrate 8 possessing a Z-Me group at the terminus was approximately twofold greater than that of compound 9 with an E-Me group. Thus, the Me-30 group is essential for the correct folding of a chair-chair-chair-boat-boat conformation of compound 1 for the production of the ß-amyrin scaffold, whereas the Me-24 group exerts little influence on the normal polycyclization cascade. Here, we show that the Me-30 group plays critical roles in constructing the ordered architecture of a chair-chair-chair-boat-boat structure, in facilitating the ring-expansion reactions, and in performing the final deprotonation reaction at the correct position.