Clozapine過量導致嚴重酸中毒並產生戒斷後瞻望及肌張力不全

Severe Acidosis Followed by Withdrawal Delirium and Dystonia-like Movement after Clozapine Overdose

背景：可自律接受器的複雜性導致多樣化的中毒及戒斷症狀。個案報告：使用約5,000 毫克可自律之精神分裂症病人，產生嚴重乳酸中毒、癲癇發作及呼吸衰竭。經急救及加護病 房治療後，恢復意識。在停藥4 天後，出現肌張力不全、膽妄、嚴重出汗及精神症狀惡化等 現象，此些症狀於調增可自律劑量後漸趨緩解。結論：可自律過量是危險可致命的，所造成 乳酸中毒可發生在尚未有明顯呼吸抑制狀態下。可自律戒斷症狀與多重機制相關，臨床需特 別預防突然停藥後所造成的戒斷症狀。

Background: Due to receptor-binding complexity of clozapine, the symptoms of its overdose and withdrawal are complicated and vary greatly in different patients. Case Report: The case report describes a schizophrenic patient who took 5,000 mg clozapine in a suicidal attempt. He suffered from metabolic acidosis, generalized tonic and clonic seizures with respiratory failure. The patient regained clear consciousness after clozapine was withheld. Delirium, dystonia-like movement and rebound psychosis emerged on the 4th day. Clozapine withdrawal was the most likely the cause, and above-symptoms were improved gradually after clozapine was reloaded. Conclusion: We suggest that clozapine overdose may lead to lactic acidosis even without the complications of hypotension and respiratory failure. Several mechanisms are attributed to the various presentations of clozapine withdrawal. The manifestations in our patient underscored the risk of severe acidosis after clozapine overdose and the importance of prevention of clozapine withdrawal.