Prazosin is an alpha-adrenergic blocker used to treat hypertension and benign prostatic hypertrophy. The drug also antagonizes norepinephrine at brain postsynaptic alpha-1 adrenoreceptors, and a pilot study has investigated its possible use to treat agitation and aggression in Alzheimers disease (Wang et al. Am J Geriatr Psychiatry 2009; 17: 744-751). Prior studies have suggested that an increased number of alpha-1 adrenoreceptors is correlated with aggressive behaviour (Sharp et al. Am J Geriatr Psychiatry 2007; 15: 435-437).