Abstract
Committee on Psychotropic Drugs and Other Physical Treatments, Royal Australian and New Zealand College of Psychiatrists, Melbourne, Australia:
With regard to current guidelines for sedation of the acutely disturbed patient, the College generally follows recommendations in the Victorian Medical Postgraduate Foundation (VMPF) Psychotropic Drug Guidelines [1]. These include a management decision tree and options of oral and parenteral medication. Under parenteral medication, first-line therapy should be with a benzodiazepine and intramuscular injections should be used, except where rapid sedation is required. If an intravenous benzodiazepine is required, diazepam is recommended; alternatively, droperidol 5–10 mg intramuscularly or haloperidol 5–10 mg intramuscularly. ‘Where there is an urgent need to achieve sedation and where ben-zodiazepines are contra-indicated or have been ineffective, haloperidol 5–10 mg can be given intravenously’ with benztropine by intramuscular injection [1]. The VMPF Psychotropic Drug Guidelines also address issues of restraint, monitoring of vital signs and availability of resuscitation equipment. The next edition of the VMPF guidelines is due in the year 2000.
Furrows [2] raised his concerns with this Committee. We noted that the reports of Torsades de Pointes described by both the Hunt and Stern [3] and Sharma et al. [4] articles refer to critically ill patients and high doses of haloperidol, in some cases extremely high doses, as much as haloperidol 200 mg intravenously in a single dose. We are aware of marked differences in approaches to acute sedation in different countries, including the use of very high doses of intravenous haloperidol in severely medically ill patients in the USA.
Lawrence and Nasraway [5] conducted Medline and manual searches of literature published from 1966 to 1996 and identified articles describing 18 patients with conduction disturbances associated with ‘therapeutic dosages’ of droperidol or haloperidol. They noted that the majority of cases occurred in critically ill patients prescribed more than 50 mg/24 h of either agent. Of the 18 patients described, 13 (72%) had a history of cardiovascular disease. They suggest that based on the small number of available case reports, it seems reasonable to suggest that the incidence of adverse cardiovascular disease effects due to droperidol and haloperidol is small.
They recommend that ‘Before initiating therapy with droperidol or haloperidol in critically ill patients, a baseline QTc interval and serum magnesium and potassium concentrations should be measured…’ ‘All critically ill patients receiving droperidol or haloperidol should undergo electrocardiogram monitoring and QTc interval measurement; special attention should be given to those receiving doses greater than 50 mg/24 h, as these patients appear to be at greatest risk for development of conduction disturbances…’.
Although the doses of haloperidol used in critically ill patients in these reports seem much higher than those used in Australia, it seems reasonable to advise liaison psychiatrists of the small risk of Torsades de Pointes. We would expect that medically ill patients would have had electrocardiograms and electrolytes as part of their routine care.
With regard to the use of intravenous haloperidol in acute psychiatry, we agree that its use is not necessary very often. Ready availability of resuscitation equipment and regular monitoring of vital signs are prerequisites for its use. However, the consensus is that the use of intravenous haloperidol in modest dosage can still have a place in difficult situations and its use should not be proscribed.