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BackgroundAlthough cis-diamminedichloro-platinum (CDDP) exhibits strong therapeutic effects in cancer chemotherapy, its adverse effects such as peripheral neuropathy, nephropathy, and vomiting are dose-limiting factors. Previous studies reported that chronotherapy decreased CDDP-induced nephropathy and vomiting. In the present study, we investigated the influence of dosing times on CDDP-induced peripheral neuropathy in rats.MethodsCDDP (4 mg/kg) was administered intravenously at 5:00 or 17:00 every 7 days for 4 weeks to male Sprague–Dawley rats, and saline was given to the control group. To assess the dosing time dependency of peripheral neuropathy, von-Frey test and hot-plate test were performed.ResultsIn order to estimate hypoalgesia, the hot-plate test was performed in rats administered CDDP weekly for 4 weeks. On day 28, the withdrawal latency to thermal stimulation was significantly prolonged in the 17:00-treated group than in the control and 5:00-treated groups. When the von-Frey test was performed to assess mechanical allodynia, the withdrawal threshold was significantly lower in the 5:00 and 17:00-treated groups than in the control group on day 6 after the first CDDP dose. The 5:00-treated group maintained allodynia throughout the experiment with the repeated administration of CDDP, whereas the 17:00-treated group deteriorated from allodynia to hypoalgesia.ConclusionsIt was revealed that the severe of CDDP-induced peripheral neuropathy was inhibited in the 5:00-treated group, whereas CDDP-treated groups exhibited mechanical allodynia. These results suggested that the selection of an optimal dosing time ameliorated CDDP-induced peripheral neuropathy.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2777-0) contains supplementary material, which is available to authorized users.

Although cisplatin (CDDP) is a key drug in cancer chemotherapy, CDDP-induced peripheral neuropathy is a dose-limiting factor. We previously reported that CDDP-induced peripheral neuropathy, which progressed from allodynia to hypoalgesia, was ameliorated by the administration of CDDP to rats at a specific time. However, mechanical allodynia cannot be prevented therapeutically. Pregabalin (PGN) is used to suppress neuropathic pain from herpes zoster and diabetes. Therefore, we investigated the effects of PGN on CDDP-induced mechanical allodynia in rats. CDDP (4 mg/kg) was administered intravenously to male Sprague-Dawley rats at 5:00 once a week for 2 weeks, while saline was given to the control group. PGN (10 mg/kg/day) was administered orally twice a day at 8:00 and 20:00, and distilled water was given to the control group. The von Frey and hot-plate tests were performed to assess CDDP-induced peripheral neuropathy. Withdrawal thresholds were significantly greater than those in with the CDDP alone group when PGN was administered before and after the onset of CDDP-induced mechanical allodynia. Furthermore, CDDP-induced mechanical allodynia was suppressed by the administration of PGN only. These results demonstrate that PGN effectively ameliorates CDDP-induced mechanical allodynia during the administration of PGN.

Linezolid is an oxazolidinone antibiotic that effectively treats methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE). Since rifampicin induces other antibiotic effects, it is combined with linezolid in therapeutic regimes. However, linezolid blood concentrations are reduced by this combination, which increases the risk of the emergence of antibiotic-resistant bacteria. We herein demonstrated that the combination of linezolid with rifampicin inhibited its absorption and promoted its elimination, but not through microsomal enzymes. Our results indicate that the combination of linezolid with rifampicin reduces linezolid blood concentrations via metabolic enzymes.

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