[Hypotensive drugs and first-dose syndrome. Considerations on 6 cases observed during treatment with ACE inhibitors]

An examination of the literature provides the basis for a definition of first dose iatrogenic hypotension or "first dose syndrome", its nature, degree and frequency. The drugs that often cause this phenomenon are listed with details of the mechanisms involved as are the physiological, pathological and iatrogenic conditions that may trigger and/or exacerbate the gravity and duration of the syndrome. In a series of patients with essential arterial hypertension treated with ACE inhibitors, 6 developed first dose syndrome, two of them after captopril and 4 after enalapril maleate, two of whom were also receiving theophylline and nitro derivates. Though wide personal experience suggests that first dose syndrome caused by ACE inhibitors is a rare event and those drugs are undeniably effective and well tolerated, treatment should always start with minimum doses administered before bed time especially in patients receiving other medication and/or presenting the physiological or pathological conditions in which first dose syndrome has already been observed and described.