Among PCPs and Pharmacists who use a branded OTC PPI. 2 Among OTC brands. Based on IRI sales data 52 weeks ending 2/14/2016. 3 It's possible while taking Nexium 24HR. Use as directed for 14 days to treat frequent heartburn. Do not take for more than 14 days every 4 months unless directed by a doctor. Not for immediate relief. 4 Use as directed for (14) days to treat frequent heartburn. Nexium 24HR may take 1-4 days for full effect.