GSK, whose other brands include Corsodyl, Oilatum and Piri, has "identified a £80m growth opportunity for over-the-counter (OTC) medicines, maximising the potential of categories which aren’t performing as well within pharmacy", said the company's general manager for northern Europe David Barnett.

The company has put "a number of steps in place to ensure that it fully supports pharmacy," it said. "A huge factor is the company's marketing investment in its power brands, which is over £60m in 2017 alone."

"This provides a direct benefit to pharmacy, as these campaigns – for brands relevant to pharmacy, such as Voltarol and Nurses – attract shoppers into pharmacy, and it helps drive awareness and sales."

Four GSK tips for boosting OTC sales

1. Make shopping easier for customers through improving shop layout
2. Encourage customers to try different products, by placing them by the till or using posters
3. Ensure pharmacists are available, personable and trustworthy
4. Train staff in knowledge and recommendations around products