Stomach acid-suppressing medicine ranitidine disappeared from pharmacy shelves two years ago, owing to fears of contamination with probable human carcinogen N-nitrosodimethylamine (NDMA).

In this episode, features editor Dawn Connelly finds out why.

She speaks with David Light, chief executive officer of Valisure, the online pharmacy that first identified the contamination in ranitidine, and Michael White, professor of pharmacy practice at the University of Connecticut, about the implications for other similar medicines.

Connelly also assesses evidence ranitidine could be about to make a comeback and discusses the problems of switching to alternative treatments with Mikin Patel, lead pharmacist in gastroenterology at Imperial College Healthcare NHS Trust, London, and Alisdair Jones, a primary care network pharmacist in Folkestone, Kent.

This episode was produced by Geoff Marsh and additional research was carried out by Emma Wilkinson.