Antacid combinations of magnesium and aluminium salts are superior to single component preparations because.
(Ref: KDT 6/e p635) Mg (OH)2 has a quick onset whereas Al (OH)3 acts for a long time. Magnesium salts cause osmotic diarrhea whereas aluminium salts cause constipation. Combination of these two agents minimizes the impact on bowel movements.
Other topics and Adverse effects
They have rapid as well as sustained acid neutralizing action
They are less likely to affect gastric emptying
They are less likely to alter bowel movement
All of the above
All of the above