Calcium-based antacids

Select two different types of antacid (e.g., magnesium-versus calcium-based antacid products). 

Hyperphosphatemia is generally benign and rarely needs aggressive therapy. Dietary restriction of phosphate and protein is effective for most minor elevations. Phosphate binders such as aluminum-based antacids, calcium carbonate, calcium acetate (PhosLo , Nabi), sevelamer (Renagel , Genzyme), and lanthanum carbonate (Fosrenol , Shire) may be necessary for some patients.43 If patients exhibit findings of hypocalcemia (tetany), IV calcium should be administered empirically. 

Citrate Since it occurs to the extent of about 0.1 nM in the blood plasma, citrate becomes the pre-eminent small molecule plasma binder of a metal ion like Al3+ that prefers oxygen donor ligands. Citrate complexion of Al3+ in the upper gastrointestinal tract with a pH of 2 to 5, may form a zero-charged complex that may pass through membranes. Sodium citrate as well as calcium citrate may cause a 100-fold enhancement of gastrointestinal Al absorption. The adsorption of Al from Al(OH)3-based antacid rises substantially upon intake of citrate, and therefore these antacids should not be taken with citrus fruit or juices [190]. 

There seem to be no direct clinical studies with calcium-containing antacids, but a clinically important interaction seems almost a certainty, based on in vitro studies with calcium carbonate, calcium in milk, (see Tetracyclines + Food or Drinks , p.347), dicalcium phosphate, and calcium as an excipient in tetracycline capsules. 

A recent consensus panel recommends calcium- or magnesium-containing antacids as first-line therapies for heartburn in pregnancy.21 This recommendation was based on the added benefit of calcium and magnesium supplementation. Avoid antacids containing aluminum hydroxide owing to associations with fetal neurotoxicity.22... 

Inorganic compounds such as aluminium hydroxide, sodium bicarbonate, and magnesium and calcium carbonates are commonly used as antacids. There is much scope for the redesign of these agents to achieve fine control of local pH values in the gastrointestinal tract via control of the rate of release of the active bases (e.g., from insoluble compounds). 

If the chalk is made of calcium carbonate, CaCO, it is made of the same active ingredient found in many antacids. The calcium carbonate is a base that reacts to neutralize any excess acids. Be careful, though, never to take too much calcium carbonate because the stomach is designed to always be somewhat acidic. 

Antacids attempt to chemically neutralize stomach acids. These drugs typically contain a base such as carbonate or hydroxide combined with aluminum, magnesium, or calcium.34 The base combines with excess hydrogen ions (H+) in the stomach to increase intra-gastric pH. The basic strategy of this chemical neutralization is illustrated in Figure 27-1. 

Because acid-pepsin disease rarely occurs in the absence of gastric acid and pepsin, antacids are highly effective in its overall management. Antacids consist of a mixture of magnesium, aluminum, and calcium compounds. Their efficacy is based on their inherent ability to react with and neutralize gastric acid. Sodium bicarbonate, which may leave the stomach rapidly, can cause alkalosis and sodium retention. Calcium salts may produce hypercalcemia, which can be detrimental in patients with impaired renal function. Aluminum salts may decrease the absorption of tetracyclines and anticholinergic drugs. 

Antacids are basic substances that reduce gastric acidity by neutralising HCl. The hydroxide is the most common base but trisilicate, carbonate and bicarbonate are also used. Therapeutic efficacy and adverse effects depend also on the metallic ion with which the base is combined, and this is usually aluminium, magnesium or sodium. Calcium and... 

Although antacids contain other ingredients, all antacids contain a base that counteracts stomach acid. The base is either sodium hydrogen carbonate, NaHCOs, calcium carbonate, CaCOs, aluminum hydroxide, Al(OH)c , or magnesium hydroxide, Mg(OH)2. 

The same principle applies to acid indigestion. Rather than swallow lye (ugh ) or some other strong base to neutralize excess stomach acid, most people take antacids. Antacids typically contain salts such as calcium carbonate, sodium hydrogen carbonate (sodium bicarbonate), and magnesium carbonate, all of which are salts of weak acids. These... 

Aluminum hydroxide, magnesium hydroxide, and calcium carbonate are all used as antacids. Write the balanced equations that show how these bases react with HCl. How many moles of stomach acid (HCl) will 1.0 g of each of these anatacids neutralize ... 

Bases also constitute the active ingredient in antacids. There are hundreds of different brands of antacids, most of which contain one or more of the following bases sodium bicarbonate (NaHCOj), calcium carbonate (CaCOj), magnesium carbonate (MgC03), magnesium hydroxide (MglOHlj), and aluminum hydroxide (A1(0H)3). These antacids dissociate in water to produce a metal ion and a base. Sodium bicarbonate, for example, produces sodium ions and basic bicarbonate ions (HCOj ) in solution ... 

Antacids are substances that neutralize excess stomach acids. They typically contain basic substances such as aluminum hydroxide, calcium carbonate, magnesium hydroxide, and sodium bicarbonate, alone or in combination, which remove acid by neturalization acid + base = salt + water. 

Antacids are used for heartburn relief. They are bases (a base is an anti-acid, or the chemical opposite of an acid), and they work via an acid-base reaction that neutralizes some of the acid in your esophagus and stomach. The active ingredient in Turns and other similar products is calcium carbonate ... 

Calcium hydroxide also is an ingredient in some stomach antacids, as shown in Figure 2.3. In the stomach, it reacts with hydrochloric, neutralizing its effects. These neutralization reactions are dealt with in more detail in the chapter on acids and bases. 

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