Mairo Mandara is a Nigerian doctor tackling a scandal involving cough syrup containing the painkiller, codeine. Codeine can be addictive and in Nigeria thousands of people have been drinking this syrup by the bottleful to get a fix. The Nigerian government recently banned the import and manufacture of the syrup. Dr Mandara, a former surgeon and former country director of the Bill and Melinda Gates Foundation in Nigeria, tells us why she's willing to risk her life to end codeine cough syrup addiction. (Photo credit: BBC.)