GASTROENTEROLOGY

What Is Gastrointestinal Reflux Disease?

GERD

Gastrointestinal reflux disease occurs when the contents of the stomach splash back into the esophagus. Learn what causes GERD and how it's treated.

What is the Gastrointestinal Tract?

The gastrointestinal, or GI, tract includes the oral cavity, pharynx, esophagus, stomach, and the small and large intestine. The GI tract is part of the digestive system, and it is responsible for moving food and liquid into and out of the body.

At the junction of the esophagus and the stomach lies a muscle called the lower esophageal sphincter, which opens to allow food to enter the stomach and then closes to keep food and stomach acids from flowing back into the esophagus.
What Causes Gastroesophageal Reflux Disease (GERD)?

If there is too much pressure in the stomach, or if the sphincter muscle is not functioning properly, then contents of the stomach can splash back into the esophagus, causing symptoms of gastroesophageal reflux disease, or GERD.
Symptoms of GERD

These symptoms may include heartburn, chest pain, coughing or choking while lying down, or increased asthma symptoms while sleeping.
Treating GERD

Diet and lifestyle changes can relieve some of the symptoms associated with GERD; however, in some cases medication or surgery are necessary.

GERD
"Pharmacodynamic Aspects of H2-Blockers versus proton Pump Inhibitors.
" U.S. Food and Drug Administration. 14 Mar 2007
(http://heartburn.about.com/od/medsremedies/a/protonpumpPPIs.htm)


Cimetidine, ranitidine, famotidine and nizatidine, the currently marketed over-the-counter
Hz blockers, principally act via competitive inhibition of Hz receptors located on the
parietal cells of the stomach.

Omeprazole, the prototype proton pump inhibitor, is a highly specific inhibitor of the
proton pump in the parietal cells of the stomach, thus inhibiting gastric acid secretion.

Both Hz blockers and PPIs have been shown to cause dose-related suppression of basal
gastric acid secretion. They both are potent antisecretory agents. However, they exhibit
marked differences in their pharmacodynamic activities of inhibition of gastric secretion.

PPIs are themselves devoid of antisecretory activity. Under the highly acidic conditions
found in the parietal cells, a PPI is converted to the active inhibitor, a protonated
sulfanilamide, which binds covalently to the proton pump and inhibits it.

In general, while H2-blockers have a rapid onset of action (< 1 hr) and a duration of less
than 12 hrs, PPIs have a delayed onset of action and a prolonged duration of activity (up
to 3 days).

The pharmacodynamics of famotidine is representative of the general pharmacodynamic
characteristics of HZ blockers. The onset of the antisecretory effect of famotidine is
within 1 hr after oral administration, while the peak effect is achieved within 1-3 hrs.
Inhibition of basal secretion by a single 40 mg oral dose of famotidine results in
elevations of the intragastric pH to > 4.5 for up to lo-12 hrs (Chremos A, 1987).

PPIs have short half-lives ranging from 0.8-2 hrs. However, their effect can last for up to
3-5 days after drug administration. This is primarily attributed to their mechanism of
action, which involves irreversible inhibition of the proton pump, hence, the rate limiting
step in the antisecretory action of PPIs is the turnover rate of the pump, which has a half-
life of 50 hrs. In contrast, the antisecretory activity of Hz-blockers is closely related to
drug concentrations in plasma.

The results of two studies in patients with a history of heartburn who received single oral
doses of omeprazole showed that at doses of up to 20 mg, omeprazole was not effective
in increasing intragastric pH at 1 hr postdose. In one of the two studies, famotidine 10 mg
raised intragastric pH greater than 4 more quickly than either the 10 or 20 mg doses of
omeprazole (Lind et al, 1981, Pig. l&2). In the other study, a single omeprazole 20 mg
dose did not increase intragastric pH over the first 5 hrs postdose relative to placebo
(AstraMerck, 1996, Fig. 3&4).

After repeated oral dosing, treatment with omeprazole, 20 mg once daily for 4 weeks,
resulted in a median reduction of 97% in the 24-hr intragastric acidity (Lanzon et al,
1987).
Medications That May Cause Heartburn
While we most often think of certain foods as causing heartburn, there are also some medications that may cause heartburn. This is a result of relaxing the lower esophageal sphincter (LES), irritating the esophagus, or slowing stomach-emptying.

Below are some of the medications that may cause heartburn. Each individual is different, so it's important to remember that while some medications trigger heartburn for some people, it may not be the case for you. If you do suspect that one of your medications is worsening your heartburn, it is important to talk to your primary healthcare provider. You should not stop taking your medication unless advised to do so by your doctor. While it may stop the heartburn, the consequences of suddenly stopping some medications can be worse than the heartburn.

Medications that may cause heartburn include:

Anti-anxiety medications, such as Valium or Ativan
Some antibiotics, such as tetracycline
Anticholinergics
Antihistamines, such as Benadryl (Diphenhydramine)
Aspirin
Beta blockers for high blood pressure or heart disease, such as Inderal (Propranolol), Tenormin (Atenolol)
Bisphosphonates (for osteoporosis)
Calcium channel blockers for high blood pressure, such as Procardia (Nifedipine), Cardizem (Diltiazem)
Certain bronchodilators for asthma, such as Albuterol and Metaproterenol
Chemotherapy drugs
Dopamine
Estrogen

TEN Heartburn Facts You Should Know

http://heartburn.about.com/od/understandingheartburn/a/heartburn_facts.htm
act #1:
Heartburn begins as a burning pain behind the breastbone, and it then usually radiates upward to the neck. There is often a sensation of food coming back into the mouth, and is accompanied by a sour or bitter taste in the mouth.
Fact #2:
More than 60 million American adults suffer from heartburn at least once a month, and about 25 million American adults suffer from heartburn on a daily basis.

Fact #3:
Approximately 94 percent of sufferers can link their heartburn symptoms to specific foods.

Fact #4:
80 percent of heartburn sufferers report symptoms at night. 75 percent of heartburn sufferers say nighttime heartburn awakens them during the night, or prevents them from sleeping. 40 percent say that their nighttime heartburn symptoms affects their ability to work the next day.

Fact #5:
While lifestyle habits can worsen your heartburn symptoms, and increase the number of heartburn episodes, heartburn is a medical condition with biological causes.

Fact #6:
Heartburn is caused when the lower esophageal sphincter (LES), which is located between the esophagus and stomach, is weakened or opens inappropriately. This allows acid and other stomach contents back into the esophagus, causing irritation.

Fact #7:
Lifestyle changes can often reduce the onset of heartburn. These include knowing what are the good foods and bad foods for heartburn, avoiding alcohol consumption, stop smoking and reducing stress.

Fact #8:
Heartburn is the most common symptom of gastroesophageal reflux disease, or GERD. GERD also affects infants and children and adolescents. There are several ways to prevent the heartburn in adults and children, and several preventative steps for infants.

Fact #9:
Heartburn is more common among the elderly, as well as among pregnant women.

Fact #10:
Chronic acid reflux, or gastroesophageal reflux disease, can lead to serious complications. The constant presence of refluxed acid in the esophagus can lead to conditions such as Barrett's esophagus , erosive esophagitis, esophageal strictures, and even esophageal cancer.

يتبع