Dr Austin O Carroll, a GP who specialises in addiction services, speaks to us about nitazine, a potent synthetic opioid suspected to be responsible for a spike in the number of drug overdoses in Dublin recently. He shares how two overdoses occurred in his own clinic, and gives his insights on what Ireland can do to prepare for the arrival of fentanyl.The Explainer is brought to you by The Journal. Providing open access to valuable journalism in Ireland has been the aim of The Journal for a decade. You can contribute to ensure we can keep questioning, investigating, debunking, explaining and informing at www.thejournal.ie/contribute/