These drugs are well-tolerated with few side effects reported. The ideal use of the OTC H2RAs is to administer the dose 1 h to 2 h before episodic and/or predictable occurrences of heartburn, such as before meals.
Alginate-based products (Gaviscon, GlaxoSmithKline, USA) are approved for heartburn relief only. Both in vitro and in vivo studies have shown that these agents produce their benefit by forming a ‘raft’ or foamy physical barrier that may prevent gastroesophageal reflux. Alginate products must be taken approximately one-half hour after meals to produce this effect and subsequent benefit; taking these products before or during meals destroys the ability of the alginate to form an effective raft to reside on the gastric contents. Clinical trials demonstrate that various alginate formulations produce heartburn relief significantly better than placebo; comparisons with antacids have produced varying results of benefit of one over the other.
Many herbal product manufacturers and distributors claim efficacy for their products in dyspepsia; however, there are few well-designed randomly assigned controlled trials that substantiate this, and most of these studies are in patients with functional dyspepsia. Only studies of products containing a combination of peppermint and caraway oils reported benefit over placebo, but the evidence is insufficient to support any recommendations.