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H. Pylori and Ulcers
ASK THE PHARMACIST
H. Pylori and Ulcers by Elizabeth C. McGuffey, PhD
Q: What is the occurrence rate of Helicobacter pylori in peptic ulcer disease or gastritis? A: H pylori has been identified in biopsy specimens in 90-100% of patients with duodenal ulcers, in 70% of patients with gastric ulcers, and in 50% of patients with nonulcer dyspepsia. In addition, it has been cultured from biopsies in 20-25% of healthy volunteer subjects. Dietary habits, sex, and location of residence (rural versus urban) do not appear to affect the incidence of H pylori; however, H. pylori occurs more often in older than in younger patients, and in nonwhite than in white patients. The chronic gastritis associated with "normal" aging may in fact be caused by a bacterial infection. Q: How is H pylori identified? A: Because the bacterium resides within the mucosal layer and not on the mucosal surface, biopsy is generally required for diagnosis. Specimens should be taken from several locations to avoid false negative results. Endoscopy is not useful in diagnosis because H pyloriinfected tissue can range in appearance from normal to ulcerated. These invasive tests for H pylori produce fmdings that Vol. NS34, No.7 July 1994
are both highly specific and highly sensitive, but carry significant risks. Less invasive tests for H. pylori include urea breath testing , using 13C- or 14C_ labeled urea, and blood testing for immunoglobulin G antibodies to H pylori. The cost of breath analysis may be prohibitive because of laboratory charges. Concurrent treatment with H2-blockers or antacids that increase gastric pH levels may adversely affect the specificity of the breath test. Similarly, recent use of antibiotics may temporarily affect the viability of H pylori and the sensitivity of the antibody test. As with most antibody tests, high antibody titers have great diagnostic value, whereas lower titers are inconclusive. Serological tests have shown an intrafamilial relationship, suggesting that H pylori may be contagious. H pylori is not associated with gastritis as a side effect of nonsteroidal anti-inflammatory drug (NSAID) administration or of the ZollingerEllison syndrome. Q: How is H pylori treated? A: In general, patients who should be treated for H. pylori infection include those with resistant ulcers, those with ulcer-associated complications, and those
with symptoms severe enough to require surgery. Antibiotic treatment is not beneficial in patients with gastroesophageal reflux and nonulcer dyspepsia. The recurrence of peptic ulcer disease is about 75% within one year of treatment without eradication of H. pylori. With triple therapy (description follows), the recurrence rate drops to about 25%. Although European and Australian investigators have advocated treatment to eradicate H. pylori since the early 1980s, American clinicians have been slow to follow. Combination therapy has produced better results than monotherapy. Dual therapy using amoxicillin combined with omeprazole has been shown to eradicate H pylori in 80% of patients, but generally is not as effective as triple therapy, consisting of: 1. Bismuth sub salicylate (2 tablets with meals and at bedtime). 2. Tetracycline (500 mg qid) or Amoxicillin (500 mg qid). 3. Metronidazole (250 mg tid) or Clarithromycin (500 mg tid). The drugs should be given concomitantly and for a period of not less than two weeks. The effectiveness of bismuth is well documented, but its mechanism of action
is unknown. Clarithromycin may be used in instances of metronidazole resistance. Erythromycin, though found to be effective in vitro, is ineffective clinically. Ironically, the most common side effects of triple therapy are gastrointestinal-epigastric pain, nausea, diarrhea-but are rarely severe enough to discontinue therapy. A major problem with triple therapy is compliance. Remembering to take a drug four times a day for two weeks may be a difficult assignment. Forgetting a single dose can destroy steadystate drug levels and may compromise the efficacy of the entire drug regimen . Pharmacists should stress the importance of taking these medications exactly as prescribed. It may also be beneficial to help patients set up a calendar for taking medications, and to link dosing with eve~day events to encourage compliance. A contingency plan for missed doses will also help forgetful patients. All of these regimens may be accompanied by treatment with H2-blockers. Elizabeth C. McGuffey, PhD, is a pharmacist and director of communications, Ask the Pharmacist, Inc., Chapel Hill, N C. References available on request.
The answers in this column are based on recent inquiries received by Ask the Pharmacist, Inc., a national telephone service staffed by licensed pharmacists. Consumers, pharmacists, and other health care professionals who have questions can reach Ask the Pharmacist 24 hours a day, 365 days a year, by calling (900) 4200-ASK Afee of $1.95 per minute will appear on the caller's phone bill.
AMERICAN PHARMACY
H. Pylori and Ulcers by Elizabeth C. McGuffey, PhD
Q: What is the occurrence rate of Helicobacter pylori in peptic ulcer disease or gastritis? A: H pylori has been identified in biopsy specimens in 90-100% of patients with duodenal ulcers, in 70% of patients with gastric ulcers, and in 50% of patients with nonulcer dyspepsia. In addition, it has been cultured from biopsies in 20-25% of healthy volunteer subjects. Dietary habits, sex, and location of residence (rural versus urban) do not appear to affect the incidence of H pylori; however, H. pylori occurs more often in older than in younger patients, and in nonwhite than in white patients. The chronic gastritis associated with "normal" aging may in fact be caused by a bacterial infection. Q: How is H pylori identified? A: Because the bacterium resides within the mucosal layer and not on the mucosal surface, biopsy is generally required for diagnosis. Specimens should be taken from several locations to avoid false negative results. Endoscopy is not useful in diagnosis because H pyloriinfected tissue can range in appearance from normal to ulcerated. These invasive tests for H pylori produce fmdings that Vol. NS34, No.7 July 1994
are both highly specific and highly sensitive, but carry significant risks. Less invasive tests for H. pylori include urea breath testing , using 13C- or 14C_ labeled urea, and blood testing for immunoglobulin G antibodies to H pylori. The cost of breath analysis may be prohibitive because of laboratory charges. Concurrent treatment with H2-blockers or antacids that increase gastric pH levels may adversely affect the specificity of the breath test. Similarly, recent use of antibiotics may temporarily affect the viability of H pylori and the sensitivity of the antibody test. As with most antibody tests, high antibody titers have great diagnostic value, whereas lower titers are inconclusive. Serological tests have shown an intrafamilial relationship, suggesting that H pylori may be contagious. H pylori is not associated with gastritis as a side effect of nonsteroidal anti-inflammatory drug (NSAID) administration or of the ZollingerEllison syndrome. Q: How is H pylori treated? A: In general, patients who should be treated for H. pylori infection include those with resistant ulcers, those with ulcer-associated complications, and those
with symptoms severe enough to require surgery. Antibiotic treatment is not beneficial in patients with gastroesophageal reflux and nonulcer dyspepsia. The recurrence of peptic ulcer disease is about 75% within one year of treatment without eradication of H. pylori. With triple therapy (description follows), the recurrence rate drops to about 25%. Although European and Australian investigators have advocated treatment to eradicate H. pylori since the early 1980s, American clinicians have been slow to follow. Combination therapy has produced better results than monotherapy. Dual therapy using amoxicillin combined with omeprazole has been shown to eradicate H pylori in 80% of patients, but generally is not as effective as triple therapy, consisting of: 1. Bismuth sub salicylate (2 tablets with meals and at bedtime). 2. Tetracycline (500 mg qid) or Amoxicillin (500 mg qid). 3. Metronidazole (250 mg tid) or Clarithromycin (500 mg tid). The drugs should be given concomitantly and for a period of not less than two weeks. The effectiveness of bismuth is well documented, but its mechanism of action
is unknown. Clarithromycin may be used in instances of metronidazole resistance. Erythromycin, though found to be effective in vitro, is ineffective clinically. Ironically, the most common side effects of triple therapy are gastrointestinal-epigastric pain, nausea, diarrhea-but are rarely severe enough to discontinue therapy. A major problem with triple therapy is compliance. Remembering to take a drug four times a day for two weeks may be a difficult assignment. Forgetting a single dose can destroy steadystate drug levels and may compromise the efficacy of the entire drug regimen . Pharmacists should stress the importance of taking these medications exactly as prescribed. It may also be beneficial to help patients set up a calendar for taking medications, and to link dosing with eve~day events to encourage compliance. A contingency plan for missed doses will also help forgetful patients. All of these regimens may be accompanied by treatment with H2-blockers. Elizabeth C. McGuffey, PhD, is a pharmacist and director of communications, Ask the Pharmacist, Inc., Chapel Hill, N C. References available on request.
The answers in this column are based on recent inquiries received by Ask the Pharmacist, Inc., a national telephone service staffed by licensed pharmacists. Consumers, pharmacists, and other health care professionals who have questions can reach Ask the Pharmacist 24 hours a day, 365 days a year, by calling (900) 4200-ASK Afee of $1.95 per minute will appear on the caller's phone bill.
AMERICAN PHARMACY