Teasdale has spent the last two-and-a-half years as director of global brand communications and patient advocacy at AstraZeneca, the London-listed pharma giant.
She arrives at Burson, the world's sixth largest PR firm, today.
Prior to AstraZeneca, Teasdale was global MD and partner at health-and-wellbeing agency TogoRun, and before that she worked for Chandler Chicco (now InVentiv health) and Weber Shandwick.
Kate Hawker, UK and EMEA Healthcare lead for Burson-Marsteller, said the new hire would "help us to develop our capability in key growth areas for us, such as patient centricity and advocacy".
Clients of Burson's UK healthcare team include Ferring and AstraZeneca. In addition, its UK public affairs team works with health companies Genomic Health and Gilead Sciences.
Teasdale was one of PRWeek UK's 29 Under 29 (now 30 Under 30) in 2008.