Gur H, Paz Y, Sidi Y
Department of Medicine C, Sheba Medical Center, Tel Hashomer, Israel.
Ann Pharmacother. 1996 Sep;30(9):957-9. doi: 10.1177/106002809603000908.
To report a case of acute dystonic reaction to methotrimeprazine in a patient with untreated hypoparathyroidism, emphasizing the potential increased sensitivity of hypocalcemic patients to the extrapyramidal adverse effects of antipsychotic drugs.
An 80-year-old man who had untreated hypoparathyroidism and chronic hypocalcemia developed an acute dystonic reaction 20 minutes after ingestion of methotrimeprazine 25 mg. His medical history included an ill-defined psychiatric disorder for which he had been treated with methotrimeprazine several years earlier. The patient denied having any other diseases or taking any other medications. After 4 days, the disorientation, psychomotor restlessness, dystonic grimacing, protrusion of the tongue, and speech difficulties disappeared, despite a remaining low serum calcium concentration.
A possible mechanism, by which striatal calmodulin-mediated adenylate cyclase activation is inhibited by the combined effects of phenothiazines and hypocalcemia, is discussed.
In this patient, it is not possible to ascertain whether the dystonic reaction was due to hypocalcemia, phenothiazine administration, or both. However, it is suggested that patients with hypocalcemia may be sensitive to the extrapyramidal adverse effects of antipsychotics. In addition, acute unexpected dystonic reactions to a small dose of antipsychotics warrants measurement of the patient's serum calcium concentration.
报告一例未治疗的甲状旁腺功能减退患者使用甲硫哒嗪后发生急性肌张力障碍反应的病例，强调低钙血症患者对抗精神病药物锥体外系不良反应的潜在敏感性增加。
一名80岁男性，患有未治疗的甲状旁腺功能减退和慢性低钙血症，在服用25毫克甲硫哒嗪20分钟后出现急性肌张力障碍反应。他的病史包括一种不明的精神疾病，几年前曾用甲硫哒嗪治疗过。患者否认有任何其他疾病或服用任何其他药物。4天后，尽管血清钙浓度仍低，但定向障碍、精神运动性不安、肌张力障碍性鬼脸、伸舌和言语困难消失。
讨论了一种可能的机制，即吩噻嗪类药物和低钙血症的联合作用抑制纹状体钙调蛋白介导的腺苷酸环化酶激活。
在该患者中，无法确定肌张力障碍反应是由于低钙血症、吩噻嗪类药物给药还是两者兼而有之。然而，提示低钙血症患者可能对抗精神病药物的锥体外系不良反应敏感。此外，对小剂量抗精神病药物发生急性意外肌张力障碍反应时，有必要检测患者的血清钙浓度。
