Antacids
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The document summarizes antacids, which are bases that neutralize excess stomach acid. It discusses how the body regulates pH and the issues caused by too much acid, such as indigestion and ulcers. Common antacids contain metal hydroxides or carbonates that react with hydrochloric acid in the stomach. While antacids temporarily relieve symptoms, they should only be taken short-term without medical advice due to potential side effects and drug interactions.
Antacids
- 1. Antacids By Amy Smith, Andrew Kropp, and Mohamed Bounaim
- 2. pH in the bodyThe body controls pH in cells and extra-cellular fluid Changes in H+ concentration have significant effects on activity of moleculesEspecially catalysts/enyzmesThe Gastro-intestinal (GI) tract generates and maintains different pH environments along its lengthpH is very important for controlling activity of digestive enzymes
- 3. Acidity in the stomach Acidity in the stomach is normal, but excess acidity is potentially harmfulIt is unusual compared to other organs as its pH is as low as 1-2Due to production of hydrochloric acid from structures in lining of walls = gastric glandsAcid environment kills bacteria that comes in with food, is optimum for activity of digestive enzymes
- 4. Excess Acid Factors that cause excess production of gastric juice (acidic secretion)Excess alcoholSmokingStressSome anti-inflammatory drugsLeads to problems such as:Acid indigestion: feeling of discomfort due to too much acid in stomachHeartburn: acid from stomach rising into oesophagusA.K.A. acid refluxUlcer: damage to lining of stomach wall, resulting in loss of tissue and inflammation
- 5. How to combat Excess Acid Drugs that help combat excess acid are called antacidsThey are weak bases that neutralize excess acidUsually weakly basic compounds, often metal oxides or hydroxides, carbonates or hydrogencarbonatesReact with hydrochloric acid to produce a salt and water**note that these drugs do not directly coat ulcers or induce healing, but allow stomach lining time to mend
- 6. Typical Neutralization ReactionAcid + base -> Salt + Water
- 8. Magnesium and aluminum Antacid Formulations/ Side EffectsSeveral contain both aluminum and magnesium because they complement each other Magnesium salts are faster actingAluminum compounds take longer to dissolve but have longer lasting reliefMagnesium salts act as a laxative, whereas aluminum salts cause constipation Aluminum has been linked with Alzheimer’s so intake should be limited
- 9. Other antacids Others contain metal carbonates and hydrogen carbonates which react to produce a salt, water, and carbon dioxideCarbon dioxide can cause bloating of the stomach and flatulenceTo avoid this, antifoaming agents such as dimethicone are often addedSome also contain alginates which float to the top of the stomach, which prevents reflux into oesophagus
- 11. More Side Effects/ CautionsSince antacids change the pH of the stomach, they can alter the absorption of other drugsThey should NEVER be taken for an extended period without medical supervision
- 12. Exercise 3 Magnesium hydroxide and aluminum hydroxide can act as antacids A) Write an equation for the reaction of hydrochloric acid with each of these antacidsB) Identify which antacid neutralizes the greater amount of acid if 0.1 mol of each antacid is used.Al(OH)3 reacts with H+ in a mole ratio of 1:3; Mg(OH)2 reacts with H+ in a mole ratio of 1:2 so 0.1 mol Al(OH)3 will neutralize the greater amount of C) Suggest why potassium hydroxide is not used as an antacidKOH is a strong alkali so would be dangerous for body cells; it is corrosive and would upset the pH