The moderate level of P-gp mediated transport and low affinity of SV, SVA, and AVA for P-gp inhibition compared to systemic drug levels suggest that drug interactions due to competition for P-gp transport is unlikely to be a significant factor in adverse drug interactions. Moreover, the inconsistencies between P-gp inhibition studies and P-gp transport of SV, SVA, and AVA indicate that the inhibition studies are not a valid means to identify statins as Pgp substrates.
ABSTRACT, with a t 1/2 value of 59 min. In vitro autoradiography studies on rhesus monkey brain slices identified the highest level of binding in the cerebellum, brainstem, and meninges. Finally, as an index of central nervous system penetrability, the in vivo cerebrospinal fluid/plasma ratio was determined to be 2 to 3% in cisterna magna-ported rhesus monkeys.Migraine is one of the most prevalent and disabling neurological disorders, with characteristic symptoms that can last for several days. Despite its severity and high prevalence, migraine is not generally recognized as a serious medical condition and the societal burden is not fully appreciated. Migraine often affects people during their most productive years, which in turn burdens families and employers and ultimately affects the quality of life of the migraine sufferer. Migraine is generally agreed to be underdiagnosed and many migraineurs do not receive appropriate therapy, indicating there is significant room for improvement in the diagnosis and management of migraine.An overall improvement in migraine treatment occurred Article, publication date, and citation information can be found at
The effects of different fibric acid derivatives (bezafibrate, clofibrate, clofibric acid, fenofibrate, fenofibric acid and gemfibrozil) on human organic anion transporting-polypeptide 1B1 (OATP2, OATP-C, SLC21A6), multidrug resistance protein 2 (MRP2/ABCC2) and MDR1-type P-glycoprotein (P-gp/ABCB1) were examined in vitro. Cyclosporin A (a known inhibitor of OATP1B1 and P-gp), MK-571 (a known inhibitor of MRP2) and cimetidine (an organic cation) were also tested. Bezafibrate, fenofibrate, fenofibric acid and gemfibrozil showed concentration-dependent inhibition of estradiol 17-beta-D-glucuronide uptake by OATP1B1-stably transfected HEK cells, whereas clofibrate and clofibric acid did not show any significant effects up to 100 microM. Inhibition kinetics of gemfibrozil, which exhibited the most significant inhibition on OATP1B1, was shown to be competitive with a Ki = 12.5 microM. None of the fibrates showed any significant inhibition of MRP2-mediated transport, which was evaluated by measuring the uptake of ethacrynic acid glutathione into MRP2-expressing Sf9 membrane vesicles. Only fenofibrate showed moderate P-gp inhibition as assessed by measuring cellular accumulation of vinblastine in a P-gp overexpressing cell-line. Cyclosporin A significantly inhibited OATP1B1 and P-gp, whereas only moderate inhibition was observed on MRP2. The rank order of inhibitory potency of MK-571 was determined as OATP1B1 (IC50: 0.3 microM) > MRP2 (4 microM) > P-gp (25 microM). Cimetidine did not show any effects on these transporters. In conclusion, neither MRP2- nor P-gp-mediated transport is inhibited significantly by the fibrates tested. Considering the plasma protein binding and IC50 values for OATP1B1, only gemfibrozil appeared to have a potential to cause drug-drug interactions by inhibiting OATP1B1 at clinically relevant concentrations.
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