2019 Volume 65 Issue 2 Pages 39-48
The definitive diagnosis of vertebrobasilar insufficiency (VBI) at ear, nose and throat clinics is difficult. In addition, there is no established treatment policy for VBI at present. Therefore, VBI is generally diagnosed based on the "Diagnosis from Medical History" of "Materials for Standardization of Vertigo Diagnosis" prepared by the Japan Society For Equilibrium Research, with severity scoring (VBI score) additionally performed. In our previous study, treatment was administered orally to three groups: A (ATP + dilazep hydrochloride), B (ATP + ibudilast) and C (ATP + dilazep hydrochloride + ibudilast). Only in Group C the Dizziness Handicap Inventory (DHI) score show no significant improvement from the initial diagnosis to two weeks after starting treatment or from two weeks to four weeks after starting treatment. Furthermore, the VBI score, which focused on specific symptoms in VBI, improved significantly both from treatment initiation to two weeks later and from two weeks to four weeks later. Therefore, the regimen given to Group C was considered to be the most appropriate treatment for VBI. Building on the findings of that previous report, the subjects in this study were divided into two groups: D (ATP + ibudilast + tofisopam) and E (ATP + diphenidol). Autonomic nervous adjustment drugs have been reported to be effective for VBI, although we did not explore these agents in the previous report. Diphenidol reportedly exerts a spasm inhibitory effect by improving the blood flow and vascular smooth muscle activity of the vertebral artery, so we examined the effectiveness of diphenidol for VBI and compared the effects with Group C. In Group D, the VBI score was significantly improved from both the initial diagnosis to two weeks as well as four weeks later, the same result as seen in Group B. The DHI score was significantly better in Group D than in Group B from both the initial diagnosis to two weeks later as well as to four weeks later. In Group B, however, there was a significant difference in the DHI score only from the initial diagnosis to four weeks later. Taken together, these findings indicate a synergistic effect on the DHI score, but not on the VBI score, after adding tofisopam to the ATP + ibudilast regimen. In Group E, the VBI score improved significantly from both the initial diagnosis to two weeks as well as to four weeks later. However, no significant improvement was noted from two weeks to four weeks after starting treatment. The VBI score at four weeks after starting treatment was as good as that in Group C (ATP + dirazep hydrochloride + ibudilast). In contrast, regarding the DHI scorein Group E, the DHI score improved from the initial diagnosis to 4 weeks later by 15.7 ± 22.4 points, which was lower than the respective value of 25.0 ± 26.4 points in Group C. Taken together, these findings indicate that although diphenidol is effective for improving the symptoms specific to VBI, it was considered insufficient for improving the impairment of daily life caused by dizziness. Dirazep hydrochloride is effective for improving the symptoms specific to VBI , however, the drug cannot be administered in Japan since it is not covered as a treatment for VBI by the Japanese National insurance system. When anticoagulants have already been administered, ibudilast is difficult to use. In such a case, diphenidol is considered a relatively effective therapeutic agent for VBI.
