Hindawi Publishing Corporation Case Reports in Medicine Volume 2011, Article ID 283672, 6 pages doi:10.1155/2011/283672 Case Report Prolonged Refractory Hypotension following Combined Amlodipine and Losartan Ingestion Responsive to Metaraminol James O. M. Plumb,1 Craig Stewart,2 Michael Eddleston,3, 4 and Thearina de Beer1 1 Department of Intensive Care Medicine, Nottingham University Hospitals Trust, Queen’s Medical Centre Campus, Derby Road, Nottingham NG7 2UH, UK 2 Department of Elderly Medicine Royal Derby Hospital, Derby DE22 3NE, UK 3 Clinical Pharmacology Unit, University of Edinburgh, Edinburgh EH4 2EH, UK 4 National Poisons Information Service-Edinburgh, Royal Inﬁrmary of Edinburgh, Edinburgh EH16 4SA, UK Correspondence should be addressed to James O. M. Plumb, jamieplumb@doctors.org.uk Received 18 January 2011; Accepted 16 March 2011 Academic Editor: M. E. Safar Copyright © 2011 James O. M. Plumb et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Introduction. Overdose with the calcium channel blocker amlodipine can cause profound hypotension that may be exacerbated by the concurrent ingestion of an angiotensin II receptor antagonist. Best management of such overdoses is uncertain although the use of hyperinsulinaemia-euglycaemia (HIE) has been recommended. Case report. We report a case of mixed amlodipine and losartan overdose in a 50-year-old lady. Severe hypotension was resistant to conventional vasopressors and high-dose insulin/euglycaemia, but did respond to a metaraminol infusion. Conclusion. A trial of metaraminol early in severe cases of calcium channel blocker and angiotensin II receptor antagonist toxicity may be of beneﬁt, especially when conventional ionotropic treatment measures are failing. 1. Introduction Severe calcium-channel blocker overdose of the dihydropy- ridine class has a profound eﬀect on the systemic vascular resistance. Of the dihydropyridine class, amlodipine is often favoured for its once daily dosing, lack of negative ionotropy, and prolonged duration of eﬀect (which can last up to 72 hours) [1]. Conventional treatment of calcium channel blocker overdose centres on increasing transmembrane cal- cium ﬂow either by increasing extracellular calcium concen- tration or by increasing intracellular cAMP concentration, which can be achieved by adenylate cyclase stimulation (adrenaline or glucagon) or phosphodiesterase inhibition (amrinone, milrinone) [2]. However, no controlled trails have been conducted, and treatment successes or failures have been reported in almost equal measure [3–8]. Angiotensin II receptor blockers (in this case Losartan) bind at the AT1 receptor and inhibit vasoconstriction, sympathetic activation, peripheral noradrenergic transmis- sion, baroreceptor desensitisation, endothelin release, renal sodium reabsorption, adrenal cortical aldosterone release, and nitrous oxide destruction [9, 10]. The combination of an angiotensin II receptor blocker and a calcium channel blocker could produce a synergistic toxicity by limiting the eﬀectiveness of both endogenous and exogenously administered catecholamines [11]. Treatment for a mixed overdose in these patients have included: intravenous ﬂuid guided by central venous pres- sure, calcium chloride/gluconate boluses/infusion, glucagon boluses or infusion, atropine, isoprenaline, high dose nora- drenaline/adrenaline, vasopressin/terlipressin, haemoperfu- sion, hyperinsulinaemia-euglycaemia, and intralipid. [3–8, 11–17]. Hyperinsulinaemia-euglycaemia in the treatment of severe calcium channel blocker overdose is not without controversy. Its eﬀectiveness has never been rigorously established [14]. It has been proposed that failure of hyperinsulinaemia-euglycaemia in severe calcium channel blocker overdose has sometimes been due to inadequate dosing and speed of starting treatment [2, 14].