高齢双極性障害に対するバルプロ酸とリチウムの安全性と予防効果に関する後方視的検討

Safety and Prophylactic Effect of Valproate Compared with Lithium in Elderly Bipolar Disorder Patients：A retrospective study

抄録

　55歳以上でバルプロ酸またはリチウムが処方開始された双極性障害(高齢群)について，その安全性と予防効果を，30～45歳で処方開始された症例(若年群)と比較しながら後方視的に調査した。重度の副作用はリチウム高齢群のみで3例認められた。バルプロ酸は高齢群ではリチウムよりも安全性が優れていたが，薬剤間に予防効果の差はなかった。バルプロ酸では年齢群間に予防効果の差は認められなかったが，リチウムは高齢群のほうが若年群よりもうつ病相の予防および総合判定で優っていた。以上より，高齢双極性障害では特に安全性の面でバルプロ酸がリチウムよりも有益と考えられたが，今後，腎機能や脳器質性の要因も含めて前方視的な検討が望まれる。

Summary

　It is still uncertain that valproate is more useful than lithium in the treatment for elderly patients with bipolar disorders (BD). We retrospectively investigated safety and efficacy of valproate and lithium in all the patients with BD who were currently outpatients visiting the department of psychiatry, Hokkaido University Hospital, and had started to be treated by either drug when they were 55 years old or older, comparing them with patients who sarted using either drug when they were 30 to 45 years old. Younger subjects were matched by sex to and randomly extracted so that the number of patients was the same as the number in the elderly group for each drug, N＝31 (F＝15, M＝16) for valproate, N＝49 (F＝23, M＝26) for lithium. The mean periods prescribed, the mean serum concentrations during the maintenance phase, and the severity of side effects did not significantly differ between the two age groups for each drug. Severe side effects were observed only in the elderly lithium-prescribed group (n＝3). In 22 elderly patients, who had received both of the drugs separately, severity of side effects was significantly worse when taking lithium than valproate while the prophylactic benefit the obtained was approximately the some no matter which of the drugs were used. There was no significant difference in the prophylactic effect of valproate between the two age groups. As regards lithium, more beneficial CGI scores for prophylaxis were noticed in elderly subjects than in younger subjects in both depression and overall bipolar illness, but not in cases of mania. However, the rates of ‘very much improved’ and ‘much improved’ patients in all CGI scales for prophylaxis did not differ according to the age groups for lithium. In conclusion, although lithium might have some advantages of efficacy in use for elderly patients compared to younger patients, valproate is considered to be more useful especially in terms of safety than lithium in the treatment for elderly BD.