Loxapine succinate as a neuroleptic agent: evaluation in two populations of elderly psychiatric patients

Loxapine delivered as a thermally generated aerosol does not prolong QTc in a thorough QT/QTc study in healthy subjects

The objective of this study was to establish effects of inhaled loxapine on the QTc interval in this randomized, placebo-controlled, double-blind crossover study. Forty-eight healthy volunteers received a single inhaled placebo or 10 mg loxapine. Plasma concentrations of loxapine increased with a median Tmax of 1 minute and a mean Cmax of 312 ng/mL. After an initial rapid distribution phase, plasma concentrations of loxapine declined with a terminal half-life of 8 hours. Exposure to the active metabolite 7-OH-loxapine was 15% of the parent compound based on mean AUCinf and its terminal half-life was 12 hours. Inhaled loxapine did not increase QT intervals, as demonstrated by the upper bound of the 1-sided 95% CIs placed on the point estimate of the placebo-subtracted change of QTcI (ΔΔQTcI) being less than 10 milliseconds at all 11 post-dose times. The maximum ΔΔQTcI occurred at 1 hour post-dose (LSmean 5.42 milliseconds, upper confidence bound 7.75 milliseconds). The study outcome was validated by the demonstrated assay sensitivity using the positive control moxifloxacin maximum ΔΔQTcI occurred at 3 hour post-dose (LSmean 8.36 milliseconds, lower confidence bound 5.82 milliseconds). The analyses of QTc outliers, and the lack of emergent diagnostic findings for QTcI, QTcB, and QTcF; and simple mean placebo-subtracted changes of QTcI and QTcF supported the primary QT analysis conclusion that this is a negative finding and there is no apparent QT prolongation associated with the therapeutic dose of inhaled loxapine.

Psychosis, behavioral disturbance, and the use of neuroleptics in dementia

Despite the widespread use of psychotropic agents in patients with dementia, there is little available research on the nature and prevalence of psychiatric disturbance and behavioral syndromes requiring this treatment, and the results of such therapy. The authors suggest strategies to overcome difficulties inherent in attempting to obtain symptom profiles in demented patients. There is weak evidence to support the use of neuroleptics in the treatment of symptoms like suspiciousness, hallucinations, sleeplessness, agitation, emotional liability, and aggressiveness; no individual neuroleptic can be considered superior to any other for this purpose. Few studies have evaluated the effect of neuroleptics on activities of daily life (ADL), and no study has used detailed neurophsychological evaluation to examine their effects on cognitive function in dementia.

Pharmacologic treatment of agitation associated with dementia

Pharmacotherapy of aggressive or agitated behaviors in the dementia patient has not been studied extensively, despite the prevalence of this problem. Neuroleptics have the most support for efficacy, with shorter acting benzodiazepines demonstrating benefit on occasion. However, studies done to date indicate that these drugs are effective only for a minority of patients and that side effects frequently make patients worse. Other medications, such as propranolol, carbamazepine, or lithium, may be helpful, but their efficacy in dementia patients has not been demonstrated in placebo-controlled studies. Until such studies are done, their use is most appropriate in special patient groups or in patients who have failed neuroleptic or benzodiazepine treatment. More studies are needed in elderly patients evaluating effectiveness of pharmacologic agents in specific types of dementia, particularly Alzheimer's disease. Most studies done to date have been of relatively short duration, usually two months or less. Because these medications often are given to dementia patients for prolonged periods, studies are needed to define the long-term clinical efficacy of these agents. In the clinical setting, these agents should be reduced periodically or discontinued to determine ongoing need. In addition, environmental, social, or behavioral methods of reducing agitated behaviors need to be explored as an adjunct to any medication trial.