Magnesium-based antacids

Drugs that may affect tipranavir include aluminum- and magnesium-based antacids, azole antifungals, clarithromycin, efavirenz, loperamide, NRTIs (ie, didanosine, zidovudine), rifamycins (rifampin), St. John s wort, tenofovir. 

The usual daily intake of phosphate is between 800 and 1200 mg/day. Absorption of phosphate may be impaired by some medications (e.g., aluminum- and magnesium-based antacids that bind phosphates) or by malabsorption syndrome. Malnourishment may result in low levels of phosphate owing to decreased food intake and decreased vitamin D intake. 

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... 

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

Sometimes, the body needs some help regulating its acid-base balance. People who experience heartburn, for example, may resort to taking an antacid to neutralize the stomach acid creeping up their esophagus. One popular antacid, milk of magnesia, is actually magnesium hydroxide. The reaction between stomach acid and milk of magnesia is a neutralization reaction ... 

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). 

Acids and bases are among the most familiar of all chemical compounds. Acetic acid in vinegar, citric acid in lemons and other citrus fruits, magnesium hydroxide (milk of magnesia) in commercial antacids, and ammonia in household cleaning products are among the acids and bases that we encounter every day. Hydrochloric acid is... 

Antacid preparations based on aluminium hydroxide sometimes contain magnesium salts (and carbonate or oxide) to offset the constipating effect of the alumina. This laxative effect of salts such as magnesium sulphate (or citrate) and other saline cathartics such as potassium sodium tartrate is due to their incomplete absorption from the digestive tract so that, by osmotic forces, they retain water in the intestinal lumen. 

Milk of magnesia, which can be taken as an antacid medicine, is a base. The chemical name for milk of magnesia is magnesium hydroxide (Mg(OH)2). Magnesium hydroxide can ease the discomfort caused by too much stomach acid. Potassium hydroxide (KOH) and sodium hydroxide (NaOH) are also bases. These chemicals, sometimes called lye, and are used in making soap. Sodium hydroxide is also an ingredient of oven and drain cleaners. Bases feel slippery and have a bitter taste. 

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. 

Acid-base titration The stoichiometry of an acid-hase neutralization reaction is the same as that of any other reaction that occurs in solution. In the antacid reaction you just read about, one mole of magnesium hydroxide neutralizes two moles of hydrochloric acid. 

Heartburn or stomach discomfort is caused by excess hydrochloric acid in the stomach. Hydrochloric acid helps break down the food you eat, but too much of it can irritate your stomach or digestive tract. An antacid product, often made from the base magnesium hydroxide, Mg(OH)2, neutralizes the excess acid. Neutralization (new truh luh ZAY shun) is the reaction of an acid with a base. It is called this because the properties of both the acid and base are diminished, or neutralized. In most cases, the reaction produces a water and a salt. Figure 20 illustrates the relative amounts of hydronium and hydroxide ions between pH 0 and pH 14. 

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... 

A mixture of magnesium hydroxide and water is commonly referred to as milk of magnesia and is used in many over the counter liquid antacids. Write a reaction that shows how magnesium hydroxide acts as a base when it dissolves in water. 

Milk of magnesia, a suspension of magnesium hydroxide in water, is a good example of this type of antacid. If you have ever used unflavored milk of magnesia, you may have noticed that it has a bitter taste, which is typical of a base. 

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 ... 

Because strong bases are completely ionized, the molarity of hydroxide ion in sodium and potassium hydroxide solutions, the monohydroxy bases, is the same as the molarity of the base itself. The OH molarity in 0.10 M NaOH is 0.10 M. In the case of Ca(OH)2, a dihydroxy base, the OH molarity is exactly two times the molarity of Ca(OH)2. Not all hydroxide compounds function well as bases because of their low solubility in water. Aluminum hydroxide, Al(OH)3, and magnesium hydroxide, Mg(OH)2 can both neutralize acids (they are used in several antacids) but neither is very soluble and cannot used to prepare solutions. 

The best known use for magnesium hydroxide is as an antacid in the form of milk of magnesia. Since magnesium hydroxide is a base, it reacts with excess stomach acid, which reduces heartburn and the discomfort of upset stomach. 

The alkaline earth hydroxides are not very soluble and are used only when the solubility factor is not important. In fact, the low solubility of these bases can sometimes be an advantage. For example, many antacids are suspensions of metal hydroxides, such as aluminum hydroxide and magnesium hydroxide. The low solubility of these compounds prevents a large hydroxide ion concentration that would harm the tissues of the mouth, esophagus, and stomach. Yet these suspensions furnish plenty of hydroxide ion to react with the stomach acid, since the salts dissolve as this reaction proceeds. 

Antacids (top left) are bases that raise the gastric luminal pM by neutralizing gastric acid (middle left). Tliey provide effective trem-ment for many dyspepsias and symptomatic relief in peptic ulcer and oesophageal reflux. Many proprieiaiy mixtures which usually contain magnesium or aluminium. salu are available. 

Antacids are bases used to neutralize the acid that causes heartburn. The most common antacid ingredients are magnesium and aluminum hydroxides, and bicarbonate or carbonate salts (Table 9.4). Baking soda (sodium bicarbonate) was used to relieve indigestion before many of the other commercial products became available. The bicarbonate ion, a basic anion of a weak acid, reacts with the hydronium ion from hydrochloric acid to form carbonic acid, which decomposes to give carbon dioxide and water. Note this is the same mechanism by which the blood buffering system neutralizes acid. 

Magnesium hydroxide Mg(OH)2 acts as a mild reactant by gently neutralizing stomach acids. When spicy or acidic foods, like tomatoes, cause problems, an antacid containing magnesium hydroxide neutralizes the acid and brings speedy relief. Table 14.2 lists a few common bases. 

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. 

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