GERD用药

If lifestyle modifications alone are unsuccessful in controlling reflux then medication will likely be the next step. Listed below (categorically in the order they are usually tried) are the different types of medication used to treat reflux or GERD, (where possible the generic name will be listed in brackets).

ANTACIDS

Simply put, these neutralize acid in the stomach. Antacids do not decrease acid production, rather work by temporarily neutralizing the acid that is in the stomach at the time they are taken. They work quickly but do not have long lasting effects.

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Anything with a high concentration of loose hydrogen ions is an acid. Stomach juice contains a large number of hydrogen ions and is therefore, an acid. Antacids, which usually contain aluminum or magnesium, are weak bases. Bases contain oxygen and hydrogen atoms that soak up loose hydrogen ions, converting them to water. Because water is neutral and antacids convert the acid to water we say they neutralize the acid. These drugs will affect only the acid that is in stomach at the time they are taken, as more acid is pumped into the stomach the effects begin to wear off.

Antacids containing magnesium can act as laxatives, whereas those containing aluminum may cause constipation.

Common antacids are:

* Maalox? (Aluminum Hydroxide and Magnesium Hydroxide)
* Mylanta? (Aluminum Hydroxide and Magnesium Hydroxide)
* Gaviscon? (Aluminum Hydroxide and Magnesium Carbonate)
* Milk of Magnesium? (Magnesium Hydroxide)


CYTOPROTECTIVE AGENTS

Carafate (Sulcralfate) & oral suspension - Helps protect the tissue of the esophagus by coating it with a thick, protective layer

Cytotec (Misoprostol) - Misoprostol is a synthetic prostaglandin. Prostaglandins are substances naturally found in the body. In the stomach they are believed to protect the inner stomach lining.

ACID BLOCKERS (H2 RECEPTOR ANTAGONIST)

Also called H2 Blockers, this class of drug works by blocking acid production.

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Histamine is a chemical produced by the body for many different purposes. It is one of the three pathways leading to acid production. When histamine (or H2) binds to H2-receptors found on cells in the stomach lining (parietal cells), it causes the cells to produce acid. This is a normal function of the body to aid in digestion. These drugs work to block the H2-receptors, stopping histamine from binding to them, ultimately reducing the amount of acid these cells create.

Listed below are commonly used acid blockers.

* Zantac?? (Ranitidine)
* Axid? (Nizatidine)
* Tagamet? (Cimetidine)
* Pepcid? (Famotidine)


Proton Pump Inhibitors or PPI's

PPI's are the most effective medication used to control reflux. They almost completely shut down the acid pumps in the stomach.

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The proton pump is the final stage in acid secretion so shutting down the proton pump provides the best defense in controlling acid by affecting not just the action of histamine but all three pathways of acid production. Proton Pump Inhibitors (PPI's) act by blocking the proton pump (hydrogen-potassium adenosine triphosphatase enzyme system-the K+/H+-ATPase) of the parietal cell. This almost completely stops acid production. Proton pump inhibitors are typically tried after histamine blockers have failed, as the cost can be more than double that of the histamine blockers. They are significantly more effective than H2 blockers and said to reduce gastric acid secretion by up to ninety-nine percent.

Because these types of meds are delayed-release, the manufacturers of these drugs recommend that they not be chewed or crushed. Omeprazole (Prilosec?) and lansoprazole (Prevacid?) are available as enteric-coated granules in capsules (referred to as "beads" or "pellets"). In addition, a new oral suspension formulation of lansoprazole was FDA-approved in January 2002.

Currently, the manufacturers of lansoprazole and esomeprazole include instructions on the administration of the granules in applesauce, water or acidic juices for oral administration. In addition, the package inserts for lansoprazole and esomeprazole state that the granules or pellets within the capsules may be administered down a gastric tube after mixing with an acidic juice or water. The marketed formulations of the PPIs limit their use to patients that can swallow. However, some of the PPIs can be made into a liquid, permitting their use for patients that cannot swallow, have difficulty swallowing, or have gastric feeding tubes. The following are preparations the pharmaceutical manufacturers suggested and have been evaluated for effectiveness relative to the capsule or tablet form.

Most commonly used in children:

* Prilosec? - U.S. /Losec? - Canada (Omeprazole) - Studies have shown that omeprazole suspension is stable for 14 days at room temperature (22° C) and for 30 days when refrigerated (4° C).
FOR ORAL ADMINISTRATION
Open capsule and add granules to an acidic beverage with a pH <5.3 (orange, cranberry, tomato, pineapple juice). Have the patient drink the beverage immediately without crushing or chewing the enteric-coated granules
Suspension for administration through gastric tube:
Administer the suspension through a gastric tube, shaking prior to administration, then flush with 10 mL of tap water and clamp the tube for at least one hour.

* Prevacid? (Lansoprazole) - In addition, an oral suspension formulation of lansoprazole (Prevacid?) was FDA-approved in January 2002. The new formulation is available as 15 mg and 30 mg strawberry-flavored packets. These packets are mixed with 2 tbsp of water just prior to ingestion. Mixing with other liquids or foods is not recommended.

Studies have shown that lansoprazole suspension is stable for 8 hours at room temperature (22° C) and for 14 days when refrigerated (4° C).
ORAL ADMINISTRATION
The enteric-coated granules of lansoprazole can be mixed with soft foods or acidic juices.
Soft foods: Empty the enteric coated granules of 1 lansoprazole capsule onto a tablespoon of applesauce, ENSURE pudding, cottage cheese, yogurt, or strained pears and administer immediately (within 30 minutes) without crushing or chewing the granules.
Juices: Granules can also be mixed with 60 ml (2 ounces) of either apple, cranberry, grape, orange, pineapple, prune, tomato, or V-8 vegetable juice and administered immediately (within 30 minutes) as long as the granules are not crushed or chewed.
Suspension for administration through gastric tube:
Administer the suspension through a gastric tube and flush with 10 mL of tap water.
Administration of the granules through a naso-gastric/gastrostomy tube:
The enteric-coated granules can also be administered through a gastric tube. According to the packet insert, the contents of 1 lansoprazole capsule can be mixed with 40 ml of apple juice and injected into a nasogastic tube. The tube should then be flushed with additional apple juice, so as to assure the complete delivery of the dose.

* Zegerid? (Omeprazole + Sodium Bicarbonate) -
o Both capsules and powder for oral suspension are immediate-release formulations. Both facilitate immediate release of omeprazole for rapid absorption with peak plasma levels being reached in ~30 minutes
o Sodium bicarbonate protects omeprazole from acid degradation by raising intragastric pH
o No enteric coating on capsules or powder for oral suspension

ZEGERID should be taken on an empty stomach at least one hour prior to a meal. ZEGERID is available either as 40 mg or 20 mg capsules with 1100 mg sodium bicarbonate. ZEGERID is also available either as 40 mg or 20 mg single-dose packets of powder for oral suspension with 1680 mg sodium bicarbonate.
Directions for Use:
Capsules: Swallow intact capsule with water. DO NOT USE OTHER LIQUIDS. DO NOT OPEN
CAPSULE AND SPRINKLE CONTENTS INTO FOOD.
Powder for Oral Suspension: Empty packet contents into a small cup containing 1-2 tablespoons of water. DO NOT USE OTHER LIQUIDS OR FOODS. Stir well and drink immediately. Refill cup with water and drink.

Other proton pump inhibitors:

* Aciphex? (Rabeprazole)
* Nexium? (Esomeprazole) - Studies have shown that omeprazole suspension is stable for 14 days at room temperature (22° C) and for 30 days when refrigerated (4° C).
ORAL ADMINISTRATION
Open capsule and add granules to an acidic beverage with a pH <5.3 (orange, cranberry, tomato, pineapple juice). Have the patient drink the beverage immediately without crushing or chewing the enteric-coated granules.
Suspension for administration through gastric tube
Administer the suspension through a gastric tube, shaking prior to administration, then flush with 10 mL of tap water and clamp the tube for at least one hour.
* Protonix? (Pantoprozole)

MOTILITY AGENTS (PROKINETICS)

Prokinetics work by moving food through digestive system faster. The rationale behind using prokinetics for treating reflux is simply that the faster food travels out of the stomach, the less chance there is for it to be refluxed. As well, some estimate as many as 50% of babies with reflux also have some degree of gastroparesis or delayed gastric emptying.

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This class of drugs work to increase the speed at which stomach contents move through the digestive track. How they do this depends on the drug itself as listed below.

* Reglan? - U.S. /Maxeran? Canada (Metoclopramide)
This drug is a dopamine antagonist which is beneficial in the GI tract where dopamine inhibits motility. It stimulates and coordinates esophageal (esophagus), gastric (stomach), pyloric (valve between the stomach and small intestine), and duodenal (small intestine) peristalsis. Peristalsis refers to the smooth, rhythmic muscle contractions that cause food to pass through the digestive tract. It also works to increase lower esophageal sphincter (LES) tone and stimulates gastric contractions. Unfortunately, metoclopramide crosses the blood-brain barrier which can cause negative (and if not discontinued-possibly irreversible) side effects such as involuntary muscle spasms, motor restlessness, and inappropriate aggression. These side effects are more common in long term use (12 or more months). MORE INFO ON REGLAN >
* Motilium? - (Domperidone) - Currently not available in the U.S.
This is also a dopamine antagonist; however, domperidone does not cross the blood-brain barrier so it does not have the undesirable side effects that metoclopramide may. It works to increase esophageal peristalsis, LES pressure and gastric contractions.
* Erythromycin - An antibiotic with the side effect of increasing gastric motility. This is currently being widely used in low doses (not the higher antibiotic doses) for delayed gastric emptying as this does not have the unfortunate side effects that are possible with metoclopramide.
* Urecholine? (Bethanchol) - Urecholine is used to treat urinary and bladder problems. It helps to empty the bladder and often stimulates gastric motility, increases gastric tone, and restores rhythmic peristalsis improving gastric emptying time.

Final Comments

Very few of the drugs used on babies and children for treating GERD have been FDA approved to do so. When a drug is used for something other than it's FDA approved usage, it's referred to as "off-label".

母乳不要摇？？？！！！

Don't Shake the Milk
Linda J. Smith, BSE, FACCE, IBCLC
Why not?
Because shaking expressed mothers' milk (or boiling or freezing it) denatures the shaped molecules of the protective proteins, leaving only the pieces - the amino acids - the parts. Lactoferrin, lysozyme, and other protective components work their protection magic when they are in their original shaped molecular structure. Some components remain intact, even during freezing, shaking or heating. They not only protect the gut from many kinds of infection, but also prevent inflammation of the gut lining. Even broken up, the separate amino acids are still really good stuff and are digested by the baby as nutrients.
Imagine a set of pop-beads assembled into a necklace or bracelet. When the beads are acting as a bracelet or necklace, they are doing their job as protective elements. When you break apart the beads, you have in your hand many individual chunks of amino acids which are then digested. Cellular components are also susceptible to damage by physical stress. After all, they are living cells. With mother's milk, you get at least two functions for the price of one. With manufactured formula, you only get the individual beads, never the necklace or bracelet. And never the living cells. So, please handle human milk gently, respectfully and kindly. It's far more than perfect food for babies - it's a living tissue and protective shield too.
? 1998 Linda J. Smith, BSE, FACCE, IBCLC
原文在这里：
http://www.bflrc.com/ljs/breastfeeding/shakenot.htm

当然网上还有些不同观点。我过去没有想到这问题，现在仔细想想。。。原因可能是偶初中化学学得太好了，已经养成了摇匀的好习惯而不是shake。美国人说shake的意思是真的shake。如果你想像一下一个立着的奶瓶，shake是上下大幅度震荡，还是很暴力的。事实上由于蛋白质有不同性质，确实有些蛋白会失去活性。原因不是上文里说的分解成氨基酸，而是失去二三级结构，准确地说就是变性了。当然其实我不知道母乳中各种蛋白的特性，所以也不知道具体哪一种会发生这种变性，或者有没有会变性的蛋白。为保险起见，母乳也好，奶粉也好混匀是应该whirling，而不是shake。如果你看见过洗衣机就明白了就是洗衣服一样在水平方向拿瓶子做圆周运动，形成漩涡。这个基本技巧是初中化学课的基本功，所有化学配液都是摇匀的，不能shake。搞生化的同学可能比较容易理解，如果这个摇匀的速度太高，就叫vortex，人手恐怕很难达到，但是如果高速vortex也是可以使有些蛋白，尤其是某些酶失活的。至于为啥shake和高速vortex可以使蛋白变性，原因也很简单，因为蛋白溶解在水中，而水是有部分晶体结构的，高速的vortex或者shake，可以形成shear force，就是侧向剪切力，使蛋白结构破坏。但是肯定不足以破坏蛋白质的一级结构。所以行不成氨基酸。离心确实很暴力，不过由于没有这个侧向剪切力，只有离心力，所以不会使蛋白失活。偶从来没有注意这个问题，嘿嘿，因为没有shake过。。。哈哈，同学们没有好好学初中化学吧？