pH, healing rate, and symptom relief in patients with GERD

Gastroesophageal reflux symptoms are common and occur in all of us from tim e to time. In others, reflux may be associated with ulcerative esophagitis. The symptoms may be aggravated by large meals, coffee, smoking and positio n. Physiological and pathological reflux can be separated by the frequency and duration of the exposure of the lower esophagus to acid Pathological re flux results in symptoms and also esophagitis and ulceration in some patien ts. Although gastroesophageal reflux disease (GERD) is considered to result from a disorder of motility in the esophagus, gastric acid and peptic acti vity are deemed pivotal to the initiation and continuation of the esophagea l damage and the development of symptoms. Acid exposure in the esophagus is normally less than 4 percent of the 24 hours with a pH below 4. An increas e over 4 percent of the time with a pH less than 4 is considered pathologic al. Hence, antisecretory drugs have become the principle approach To the tr eatment of reflux symptoms and esophagitis since they reduce the acidity of gastric juice and the activity of pepsin. Importantly: they also reduce th e volume of gastric juice available for reflux into the esophagus, There is a clear relationship between the degree and duration of acid suppr ession and the relief of heartburn and healing of esophagitis. Pharmacodyna mic studies with different dose regimens of the H-2-receptor antagonists an d the proton pump inhibitors show a difference in the degree and duration o f the antisecretory effect, and this correlates closely with the results of clinical trials with respect to the healing of esophagitis and the relief of symptoms. Proton pump inhibitors achieve healing rates by week four whic h are not achieved by H-2 receptor antagonists even after 12 weeks of treat ment. The advantage of proton pump inhibitors over H-2-receptor antagonists is due to the greater degree, longer duration of effect and more complete inhibition of acid secretion that maintains intragastric pH above 4 for a m aximal duration. Although there is no significant difference between proton pump inhibitors with respect to healing of esophagitis, symptom relief occ urs earlier with lansoprazole than omeprazole, and this is probably due to the greater oral bioavailability and faster onset of action of lansoprazole when compared to omeprazole.