Pseudomonas fluorescens cross-infection due to contaminated humidifier water.

properties at high blood concentrations. MacLeod and Lamberts3 have shown the dopamine agonist effects of high concentrations of haloperidol and pimozide on prolactin release. Seeman4 has shown that very high concentrations of some antipsychotic drugs may enhance presynaptic release of neurotransmitters, including dopamine. Altematively, at high concentrations of antipsychotic drugs maximal dopaminergic blockade may occur. Additional dosage increments would not produce further dopamine blockade, but other pharmacological effects, such as anticholinergic activity, might continue to increase and might be responsible for the presentations described. Toxic psychoses have been associated with high doses of anticholinergic drugs,5 usually combined with moderate doses of antipsychotic drugs. The episodes reported in these studies also appear to have been characterised by excitement and aggression, as in our cases.