Why should one avoid combination of Ranitidine and Sucralfate in a patient of Peptic Ulcer Disease?

The Acidic nature of the stomach is necessary for the action of Sucralfate as Sucralfate polymerizes at a pH<4 (acidic).The sticky gel-like consistency of it is due to crosslink formation within the molecule at acidic pH. Simultaneous use of H2 receptor blocker results in decrease acid production in the stomach, leading to increase in pH of the stomach which would prevent polymerization of Sucralfate in stomach, causing Failure of treatment . Sucralfate also binds bile salts; thus, some clinicians use Sucralfate to treat individuals with the syndromes of Biliary esophagitis or Gastritis (the existence of which is controversial).