New York University School of Medicine, New York, NY 10016, USA.
Clin Toxicol (Phila). 2010 Nov;48(9):945-8. doi: 10.3109/15563650.2010.527850.
Diphenhydramine is an H1 histamine antagonist that is commonly used for allergic reactions, colds and cough, and as a sleep aid. In addition to anticholinergic and antihistaminergic effects, sodium channel blockade becomes evident following diphenhydramine overdose. While seizures may occur following overdose of a diphenhydramine, status epilepticus is distinctly uncommon. We report a case with both status epilepticus and wide-complex dysrhythmias following an intentional diphenhydramine overdose.
A 36-year-old woman with a medical history of hypothyroidism on levothyroxine was brought to the emergency department with active seizures by emergency medical services after what was later determined to be a diphenhydramine overdose. One hour after an argument with her husband he found her lethargic in a locked room. Initial vital signs were: blood pressure, 90/55 mmHg; heart rate, 160 beats/min; respiratory rate 18 breaths/min; room air oxygen saturation, 99%; temperature, 99.8°F; rapid point-of-care glucose, 130 mg/dL. The generalized seizures continued for duration of 30 min, despite the intravenous administration of 8 mg of lorazepam. The patient underwent endotracheal intubation and a propofol infusion terminated her seizures. An electrocardiogram after the status was terminated which revealed a wide-complex tachycardia with QRS duration of 127 ms. The QRS narrowed after 200 mEq of intravenous sodium bicarbonate was administrated. The patient was neurologically intact upon extubation on hospital day 2. The serum diphenhydramine concentration drawn on arrival to the ED was 1200 ng/mL (9-120 ng/mL); a tricyclic screen was negative.
While seizures and sodium channel blockade are recognized complications of diphenhydramine toxicity, reported cases of status epilepticus from diphenhydramine overdose are rare. Elements of the patient's presentation were similar to a tricyclic overdose and management required aggressive control of her seizures, sodium bicarbonate therapy, and recognizing that physostigmine was contraindicated due to wide complex tachycardia.
Diphenhydramine overdose may cause status epilepticus and wide-complex tachycardia. Management should focus on antidotal therapy with sodium bicarbonate and supportive neurological management with appropriate anticonvulsants and airway protection if clinically indicated.
苯海拉明是一种 H1 组胺拮抗剂，常用于过敏反应、感冒和咳嗽，以及作为助眠剂。除了抗胆碱能和抗组胺作用外，苯海拉明过量会明显出现钠通道阻断。尽管苯海拉明过量可能会引起癫痫发作，但癫痫持续状态却明显罕见。我们报告了一例因故意苯海拉明过量而导致癫痫持续状态和宽复合性心律失常的病例。
一名 36 岁女性，患有甲状腺功能减退症，服用左甲状腺素，因与丈夫争吵后被发现昏迷在锁着的房间里，被紧急医疗服务人员带到急诊室，出现活动性癫痫发作。在与丈夫争吵一小时后，他发现她在一个锁着的房间里昏昏欲睡。初始生命体征为：血压 90/55mmHg；心率 160 次/分；呼吸频率 18 次/分；室内空气氧饱和度 99%；体温 99.8°F；即时血糖 130mg/dL。尽管静脉注射了 8mg 劳拉西泮，但全身癫痫发作持续了 30 分钟。患者接受了气管插管，并给予异丙酚输注以终止癫痫发作。癫痫持续状态终止后的心电图显示宽复合性心动过速，QRS 持续时间为 127ms。静脉给予 200mEq 碳酸氢钠后，QRS 变窄。患者在入院后第二天拔管时神经功能完好。到达急诊室时抽取的血清苯海拉明浓度为 1200ng/mL（9-120ng/mL）；三环类药物检测呈阴性。
尽管癫痫发作和钠通道阻断是苯海拉明毒性的公认并发症，但报道的苯海拉明过量引起的癫痫持续状态病例很少。该患者的表现与三环类药物过量相似，需要积极控制癫痫发作、碳酸氢钠治疗，并认识到由于宽复合性心动过速，毒扁豆碱是禁忌的。
苯海拉明过量可能导致癫痫持续状态和宽复合性心动过速。管理应侧重于使用碳酸氢钠进行解毒治疗，并根据临床需要进行适当的抗惊厥药物和气道保护的神经支持治疗。
