Carfentanil overview, update

Carfentanil is 100 times more potent than fentanyl and 10,000 to 100,000 times more potent than morphine. It is too powerful to use in human medicine as a painkiller – but is used illegally as an addictive drug, sometimes fatally. Professor Michael Cole of Anglia Ruskin University brings us up to date  on prevalence and more.