Serotonin syndrome induced by a combination of venlafaxine hydrochloride sustained-release tablets and Shuganjieyu capsules (舒肝解郁胶囊)

Abstract

A 73-year-old female took venlafaxine hydrochloride sustained-release tablets 75 mg once daily, Shuganjieyu capsule 2 capsules once every 12 hours, candesartan cilexetil 8 mg once daily, amlodipine besylate 5 mg once daily, metoprolol succinate 47.5 mg once daily, citicoline sodium 0.2 g once every 8 hours and estazolam 1 mg per night for treating depression and hypertension. On day 8, the patient developed dizziness and fever. On day 9, she had urinary incontinence and rave, the drugs were discontinued. On day 10, the patient presented delirium and increased muscle tone. On day 11, she had bilateral mydriasis, wet skin and muscle cramps. Drug-induced serotonin syndrome was considered. Cyproheptadine 6 mg once every 6 hours was administered orally. The patient′s mental state, functions of the autonomic nervous system and neuromuscular improved significantly after 2 days, then the dose of cyproheptadine was reduced to 4 mg once every 8 hours. After 4 days of treatment, the patient′s vital signs were stable and cyproheptadine was stopped. Key words: Venlafaxine hydrochloride; Serotonin syndrome; Drug interactions; Shuganjieyu capsules