By Tulip Mazumdar

While the US suffers a much discussed overdose epidemic, less attention is paid to the fact that much of the rest of the world misses out on vital painkillers such as morphine. On a chilly autumn morning in Washington DC, families huddled around President Donald Trump as he faced the world's media in the White House. Some clutched photos of lost loved ones. They had been invited to witness a historic moment in their fight to try to ensure what had happened to them would not keep happening to thousands more US families. That day, President Trump declared the opioid crisis in the US a national public health emergency. Opioid prescription painkillers result in 42 deaths every day in the country. But while the US tries to deal with its over-use of these powerful medicines, millions of people in other parts of the world are dying in agony because they can't get hold of them. "I remember waking up from my mastectomy in Mexico City. The pain was so severe that I couldn't breathe," says Felicia Knaul, who had her left breast removed several years ago. "It took about 10 minutes before the physicians could come and adjust my pain medication. [It was] not only the agony, but the fear of not wanting to breathe because of the pain." Spurred on by her experience - and the knowledge that millions of people never see their physician arrive with pain relief - Felicia Knaul decided to focus her work on pain relief, and is now a professor and international health economist in the US. She also heads up a commission, set up by medical journal The Lancet, which monitors global access to palliative care and pain relief. It uncovered an alarming statistic: that 90% of all the morphine in the world is consumed by the world's richest 10%.