"These hefty sums are a far cry from how lethal injections were initially envisaged. The use of medical drugs to kill prisoners was pioneered in 1977..."

"... in Oklahoma where officials were convinced it would be both humane and cheap – they predicted it would cost only $10 per execution." 

 From "Revealed: Republican-led states secretly spending huge sums on execution drugs/Documents obtained by the Guardian show three states paying astronomical amounts to skirt – almost certainly illegally – a ban on pharmaceuticals for lethal injections" (The Guardian). 

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