Types of Antacids Medications

Antacids are a class of drugs used to treat conditions caused by the acid that is produced by the stomach. The stomach naturally secretes an acid called hydrochloric acid that helps to break down proteins. This acid causes the contents of the stomach to be acidic in nature, with a pH level of 2 or 3 when acid secretion is active. (pH levels are a measure of acidity in the stomach: the lower the number, the greater the acidity.) The stomach, duodenum, andesophagusare protected from acid by several protective mechanisms. When there is too much acid or protective mechanisms are inadequate, the lining of the stomach, duodenum or esophagus may become damaged by the acid, giving rise to inflammation and ulcerations and their variousgastrointestinalsymptoms such as

• nausea,
• abdominal pain, and
• heartburn(due togastroesophageal refluxdisease orGERD).

抗酸药降低酸度中和(counteracting) acid, reducing the acidity in the stomach, and reducing the amount of acid that is refluxed into the esophagus or emptied into the duodenum. Antacids also work by inhibiting the activity of pepsin, a digestive enzyme produced in the stomach that is active only in an acidenvironmentand, like acid, is believed to be injurious to the lining of the stomach, duodenum, and esophagus.

It is important to note that when antacids are taken on an empty stomach they provide acid reduction for 20 to 40 minutes only because the antacid is rapidly emptied into the duodenum.

• When taken after a meal, (approximately 1 hour afterward) antacids reduce acid for at least three hours since food from the meal slows the emptying of the antacid (and food) from the stomach.
• It is important to discuss the use of antacids with a physician or pharmacist, especially if used in combination with other prescribed medications so as to avoid drug interactions.

Antacids are used commonly for symptoms such as

• heartburn,
• 腹痛(有时备注说明ibed as the sour stomach), and
• nausea resulting from a number of conditions such as
  • inflammation or
  • acid-peptic ulcers of the esophagus (esophagitis),
  • stomach (gastritis), and
  • duodenum (duodenitis)

What are the 4 main types of antacids?

• Aluminum carbonate antacidscan be used to treat and managehyperphosphatemia(abnormally elevated levels of phosphate in the blood) since they bind phosphate in the intestine and prevent it from being absorbed into the body. Because of this ability to bind phosphate in the intestine, aluminum carbonate antacids also can be used with a low phosphate diet to prevent the formation of kidney stones, since kidney stones are made up of various elements including phosphates.
• Calcium carbonate antacidsare used in conditions ofcalcium deficiencysuch aspostmenopausalosteoporosissince some of the calcium is absorbed into the body.
• Magnesium oxide antacidsare used to treat magnesium deficiencies from either diets or medications that cause magnesium depletion.
• Off-label (not FDA-approved) usesfor antacids containing aluminum and magnesium or aluminum alone include preventing bleeding fromstress-induced ulcers. Other off-label uses for antacids are treatment and maintenance of healing ofduodenalulcers and treatment ofgastriculcers.

Some antacid products may neutralize more acid in the stomach than others. The way to express the ability of an antacid to neutralize acid is by determining the antacid's neutralizing capacity (ANC). The ANC is expressed as milliequivalents (mEq) of acid that is neutralized, and it measures the ability of the antacid to neutralize acids (to a ph of 3.5 to 4). Per FDA requirements, an antacid must have a neutralizing capacity of ≥5 mEq per dose. The most effective antacids should have a high acid neutralization capacity and rapid gastric acid neutralization qualities.

• Antacids such assodium bicarbonateandcalcium carbonatehave the greatest neutralizing capacity but are not used for long periods of time due to adverse events. (Please see the sections on warnings/precautions and side effects.)

An antacid's onset of neutralizing action (how fast the drug dissolves in gastric acid) varies among different antacids.

• Sodiumbicarbonateandmagnesium hydroxidedissolve quickly and provide a rapid buffering effect,
• whilealuminum hydroxideand calcium carbonate dissolve slowly.
• Antacid suspensions generally dissolve more easily than tablets or powders. If a tablet antacid is used, however, it is advisable to chew the tablets thoroughly for maximal effectiveness.

Another difference among the antacids is the duration of action (how long it continues to neutralize the acid in the stomach).

• Sodium bicarbonate and magnesium hydroxide have the shortest duration of neutralizing action,
• while aluminum hydroxide and calcium carbonate have the longest.
• Combination aluminum-magnesium antacids have an intermediate duration of action.

• Antacids may cause dose-dependent rebound hyperacidity and milk-alkali syndrome.
• Antacids that contain aluminum hydroxide may cause constipation, aluminum intoxication,osteomalacia, andhypophosphatemia.
• Antacids that contain magnesium have alaxativeeffect that may cause diarrhea, and in patients with renal failure, they may cause increased magnesium levels in the blood, because of the reduced ability of the kidneys to eliminate magnesium from the body in the urine.

• When antacids are taken with acidic drugs (for example,digoxin[Digitek],phenytoin[Dilantin],chlorpromazine[Thorazine], [isoniazid]), they cause the absorption of the acidic drugs to be decreased, which causes low blood concentrations of the drugs, which ultimately results in reduced effects of the drugs.
• Antacids are taken with drugs such aspseudoephedrine(Sudafed,Semprex D,Clarinex-D 12hr,Clarinex-D 24hr,Deconsal,Entex PSE,Claritin D, and more), and levodopa (Dopar), increase absorption of the drugs and can cause toxicity/adverse events due to increased blood levels of the drugs.
• Antacids that contain magnesium trisilicate and magnesium hydroxide when taken with some other medications (such astetracycline) will bind to the drugs, and reduce their absorption and effects.
• Sodium bicarbonate has a strong effect on the acidity of the urine, and this can affect the elimination (excretion) of some drugs by the kidney. Thus, sodium bicarbonate inhibits the excretion of basic drugs such as奎尼丁(Quinidex,Quinidine Gluconate,Quinidine Sulfate,Quinidine Injection) and amphetamines, and increases the excretion of acidic drugs such as aspirin.

• Antacids (for example, calcium carbonate) when consumed in high doses and for long periods of time may cause acid rebound. Acid rebound is a condition in which the stomach produces even more acid after the consumption of foods and drinks. Fortunately, the effects of acid rebound are not clinically important.
• High-dose calcium carbonate and sodium bicarbonate when taken together can cause a condition called a milk-alkali syndrome. Its symptoms include headache, nausea, irritability, and weakness,hypercalcemia(high blood calcium levels), and reduced function of the kidneys.
• 大量使用醇抗酸药cause hypophosphatemia (low phosphate levels in the blood), which in severe cases could lead to muscle weakness,anorexia, and osteomalacia (softening of the bones due to defective bone mineralization).
• Antacids containing aluminum hydroxide should be used with caution in patients who have recently suffered massive upper gastrointestinal bleeding.
• For patients with conditions such ashigh blood pressure, chronicheart failure, renal failure, and those who have sodium or salt-restricted diets, it is important to pay attention to the sodium level in sodium-based antacid preparations such as sodium bicarbonate
• Antacids should not be given to children under six years of age.

• AlternaGEL (liquid)
• Aluminum Hydroxide
• Aluminum Hydroxide Gel (suspension)
• Aluminum-magnesium hydroxide sulfate (Magaldrate)
• Amphojel (tablets)
• Calcium acetate(PhosLotablets)
• Calcium carbonate
• Citra pH (solution)
• Concentrated Aluminum Hydroxide Gel (suspension)
• Concentrated Aluminum Hydroxide Gel (liquid)
• Concentrated Phillips'Milk of Magnesia(liquid)
• Dialume (capsules)
• Dulcolax(液体)
• Isopan (Liquid)
• Mag-Ox 400 (tablets)
• Magnesium Hydroxide
• Magnesium Oxide
• Magnesium Oxide (tablets)
• Magaldrate (liquid)
• Maox 420 (tablets)
• Milk of Magnesia (liquid)
• Phillips' Chewable (tablets, chewable)
• Uro-Mag (capsules)
• Riopan (suspension)
• Sodium Bicarbonate
• Sodium Citrate

Antacid combinations

• Alka-SeltzerEffervescent Tablets,
• Alamat Suspension,
• Bromo Seltzer Effervescent Granules
• Gaviscon Extra Strength Antacid,
• Gaviscon Liquid,
• Gas-X with Maalox Extra Strength Tablets,
• Maalox Regular Strength Liquid,
• MylantaAntacid Gelcaps,
• Rolaids Tablets, and
• Titralac Extra Strength Tablets, etc.